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Search for "chalcones" in Full Text gives 38 result(s) in Beilstein Journal of Organic Chemistry.
Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks
- Zhang Dongxu
Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127
- , 1,4-naphthoquinones, o-trimethylsilylphenyl triflate and chalcones have all been reacted with fluorinated nitrile imines to give a series of fluoroalkylated pyrazoles by Jasiński’s team [67][68][69][70][71][72] (Scheme 11a). Subsequently, Hu et al., Nie et al., and Ma et al. have all independently
Graphical Abstract
Scheme 1: Synthesis of trifluoromethylpyrazoles from trifluoroacetaldehyde hydrazones.
Scheme 2: Synthesis of polysubstituted pyrazolidines and pyrazolines.
Scheme 3: Asymmetric synthesis of 3-trifluoromethyl-1,4-dihydropyridazines reported by Rueping et al. [39].
Scheme 4: Synthesis of 3-trifluoromethyl-1,4-dihydropyridazine with Brønsted acid-assisted Lewis base catalys...
Scheme 5: Synthesis of CF3-pyrazoles and CF3-1,6-dihydropyridazines.
Scheme 6: Asymmetric reactions of trifluoromethylimines with organometallic reagents.
Scheme 7: Mannich-type reaction of trifluoroacetaldehyde hydrazones.
Scheme 8: Synthesis of trifluoromethylated hydrazonoyl halides.
Scheme 9: Early work of trifluoromethylated hydrazonoyl halides.
Scheme 10: [3 + 2]/[3 + 3] Cycloadditions of trifluoromethylated hydrazonoyl halides.
Scheme 11: Substrate scope for [3 + 2] cycloadditions with trifluoroacetonitrile imines reported by Jasiński’s...
Scheme 12: Synthesis of trifluoromethylated 1,2,4-triazole and 1,2,4-triazine derivatives.
Scheme 13: [3 + 2] Cycloadditions of difluoromethylated hydrazonoyl halides.
Scheme 14: Preparation and early applications of trifluoromethylated acylhydrazones.
Scheme 15: 1,2-Nucleophilic addition reactions of trifluoromethylated acylhydrazones.
Scheme 16: Cascade oxidation/cyclization reactions of trifluoromethylated homoallylic acylhydrazines.
Scheme 17: Synthesis of trifluoromethylated cyanohydrazines and 3-trifluoromethyl-1,2,4-triazolines.
Scheme 18: N-Arylation and N-alkylation of trifluoromethyl acylhydrazones.
Scheme 19: [3 + 2]-Cycladditions of trifluoromethyl acylhydrazones.
Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr4/PPh3 and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior
- Christian Schumacher,
- Jas S. Ward,
- Kari Rissanen,
- Carsten Bolm and
- Mohamed Ramadan El Sayed Aly
Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9
- studies, one of us (M. R. E. A.) felt intrigued by the potential of chemical hybridization of cholesterol through simple connections of pharmacophores including sugars, chalcones, quinolone, theophylline, and ferrocene using click chemistry [9][10][11]. Following this strategy, cholesterol was
Graphical Abstract
Figure 1: Chemical structure of three isomeric cholesterols.
Figure 2: Selected previously described cholesterol derivatives with interesting antibacterial and cytotoxic ...
Scheme 1: Stereochemical outcome of OH/N3 transformations under different conditions.
Figure 3: Top: cholesterol (1) and the less polar product from the Appel reaction, cholesta-3,5-diene (9); bo...
Figure 4: Top: the more polar product from the Appel reaction 3β-bromocholest-5-ene (4); bottom: X-ray struct...
Figure 5: Top: 3α-azidocholest-5-ene (5) obtained by treatment of 4 with NaN3 in DMF; bottom: X-ray crystal s...
Scheme 2: Mechanistic interpretation of the conversion of cholesterol 1 into diene 9, bromide 4, and azides 5...
Figure 6: Compounds (next to 4, 5 and 9) to be corrected in refs. [10] and [11]. The respective bonds are highlighted...
Tri(n-butyl)phosphine-promoted domino reaction for the efficient construction of spiro[cyclohexane-1,3'-indolines] and spiro[indoline-3,2'-furan-3',3''-indolines]
- Hui Zheng,
- Ying Han,
- Jing Sun and
- Chao-Guo Yan
Beilstein J. Org. Chem. 2022, 18, 669–679, doi:10.3762/bjoc.18.68
- Hui Zheng Ying Han Jing Sun Chao-Guo Yan College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China 10.3762/bjoc.18.68 Abstract The tri(n-butyl)phosphine-catalyzed reaction of isatylidene malononitriles and bis-chalcones in chloroform at 65 °C afforded
- functionalized spiro[cyclohexane-1,3'-indolines] in good yields and with good diastereoselectivity. On the other hand, the tri(n-butyl)phosphine-catalyzed reaction of 3-(ethoxycarbonylmethylene)oxindoles and bis-chalcones gave functionalized spiro[cyclohexane-1,3'-indolines] with different regioselectivity
- compounds [60][61][62][63][64][65][66] and in order to demonstrate the potential synthetic value of the nucleophilic phosphine-catalyzed annulation reaction, herein we wish to report the tri(n-butyl)phosphine-catalyzed reaction of isatylidene malononitriles and bis-chalcones for the synthesis of
Graphical Abstract
Figure 1: Single crystal structure of compound 3l.
Figure 2: Single crystal structure of compound 3s.
Figure 3: Single crystal structure of compound 3f’.
Figure 4: Single crystal structure of compound 5a.
Scheme 1: Proposed reaction mechanism for the compounds 3 and 5.
Figure 5: Single crystal struture of compound 8a.
Scheme 2: Proposed mechanism for the formation of dispiro compounds 8.
Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase
- Peterson de Andrade,
- Sanaz Ahmadipour and
- Robert A. Field
Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24
- developed to date. The most potent TcTS inhibitors described are non-carbohydrate-based molecules (anthraquinones [14], chalcones and quinolones [15]) with low micromolar activity, whereas sialic acid-based analogues typically show high millimolar inhibitory activity [16], with few exceptions such as a
Graphical Abstract
Figure 1: Chemical structures and reported activities of viral (A), human neuraminidases (B) and Trypanosoma ...
Figure 2: Design and synthesis of potential neuraminidase and trans-sialidase inhibitors exploiting a moiety ...
Figure 3: TcTS and neuraminidase hydrolase activity (A) as well as TcTS transferase activity (B) in the prese...
Figure 4: TcTS and neuraminidase inhibition by 1,2,3-triazole-linked sialic acid derivatives 3a–h (1 mM) usin...
Figure 5: Crystal structure of TcTS (PDB code 1MS1 – coloured red) (A) and neuraminidase (PDB code 2VK6 – col...
Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides
- Pratibha Sharma,
- Raakhi Gupta and
- Raj K. Bansal
Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173
- the asymmetric aza-Michael addition reactions. Mahe et al. reported an effective, eco-friendly and cost-effective enantioselective synthesis of 3,5-diarylpyrazolines 49 by using phase-transfer methodology. They carried out a set of reactions between chalcones 46 and N-tert-butoxycarbonylhydrazine (47
Graphical Abstract
Scheme 1: Asymmetric aza-Michael addition catalyzed by cinchona alkaloid derivatives.
Scheme 2: Intramolecular 6-exo-trig aza-Michael addition reaction.
Scheme 3: Asymmetric aza-Michael/Michael addition cascade reaction of 2-nitrobenzofurans and 2-nitrobenzothio...
Scheme 4: Asymmetric aza-Michael addition of para-dienone imide to benzylamine.
Scheme 5: Asymmetric synthesis of chiral N-functionalized heteroarenes.
Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4-c]carbazoles via domino Diels–Alder reaction
- Ren-Jie Fang,
- Chen Yan,
- Jing Sun,
- Ying Han and
- Chao-Guo Yan
Beilstein J. Org. Chem. 2021, 17, 2425–2432, doi:10.3762/bjoc.17.159
- diastereoisomers of tetrahydropyrrolo[3,4-c]carbazoles, which can be dehydrogenated by DDQ oxidation in acetonitrile at room temperature to give the aromatized pyrrolo[3,4-c]carbazoles in high yields. On the other hand, the one-pot reaction of 3-(indol-3-yl)-1,3-diphenylpropan-1-ones with chalcones or
- efficient domino reactions for the synthesis of biologically important carbazole derivatives [48][49][50][51][52][53], herein we wish to report the DDQ-mediated dehydrogenative Diels–Alder reaction of 3-(indol-3-yl)maleimides and benzoyl-substituted 3-ethylindoles with readily available chalcones for the
- this compound. Thus, the isomers 3a and 3b are diastereoisomers. It is known that the starting chalcones usually have E-configuration. The phenyl group and p-chlorobenzoyl group still exist in the trans-position in both diastereoisomers 3a and 3b as in the starting chalcone. This result clearly showed
Graphical Abstract
Figure 1: Representative bioactive carbazole derivatives.
Scheme 1: Synthesis of tetrahydropyrrolo[3,4-c]carbazoles 3a and 3b.
Figure 2: Single crystal structure of the isomer 3a.
Figure 3: Single crystal structure of the isomer 3b.
Figure 4: Single crystal structure of the isomer 4g.
Scheme 2: Proposed domino reaction mechanism for the formation of carbazoles 6.
Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones
- Jan Bartáček,
- Jan Svoboda,
- Martin Kocúrik,
- Jaroslav Pochobradský,
- Alexander Čegan,
- Miloš Sedlák and
- Jiří Váňa
Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84
- -rich chalcones. The products obtained after the addition reaction with arylboronic acids were further subjected to a regioselective Bayer–Villiger oxidation (Table 5) [3]. An enhanced protocol for the synthesis of 4-aryldihydrocoumarins (Table 6) was also presented [3], which was already mentioned
- β-(2-hydroxyaryl)enones [34]. Synthesis of enantiomerically enriched 1-aryl-1H-indenes [36]. Stepwise addition of arylboronic acids to electron-rich chalcones and Bayer–Villiger oxidation [3]. Synthesis of 4-aryldihydrocoumarins by stepwise 1,4-addition and Bayer–Villiger oxidation [3]. First report
Graphical Abstract
Scheme 1: Synthesis of optically pure 4-phenylchroman-2-one [34].
Scheme 2: Synthesis of (R)-tolterodine [3].
Scheme 3: Catalytic cycle of the Pd(II)-catalysed 1,4-addition of organoboron reagents to enones [3,26,35].
Scheme 4: Enantioselective β-arylation of cyclohexanone [38].
Scheme 5: Application of L2/Pd(OAc)2 in the total synthesis of terpenes [8].
Scheme 6: Plausible catalytic cycle for the addition of phenylboronic acid to 2-cyclohexenone catalysed by L3...
Scheme 7: Microwave-assisted addition of phenylboronic acid to 2-cyclohexenone catalysed by L4/Pd2(dba)3·CHCl3...
Scheme 8: Plausible catalytic cycle of the addition of phenylboronic acid to 2-cyclohexenone catalysed by pal...
Scheme 9: Proposed catalytic cycle for the addition of phenylboronic acids to 2-cyclohexenone catalysed by Pd...
Scheme 10: Usage of addition reactions of boronic acids to various chromones in the syntheses of potentially a...
Scheme 11: Multigram-scale synthesis of ABBV-2222 [6].
Scheme 12: Application of the asymmetric addition of phenylboronic acid to a chromone derivative for the total...
Scheme 13: Plausible catalytic cycle for the addition of phenylboronic acid to 3-methyl-2-cyclohexenone cataly...
Scheme 14: Total syntheses of naturally occurring terpenoids [10,11].
Scheme 15: Use of the L9/Pd(TFA)2 catalytic system for the synthesis of intermediates of biologically active c...
Scheme 16: Usage of a Michael addition catalysed by L9/Pd(TFA)2 in the total synthesis of (–)-ar-tenuifolene [12].
Scheme 17: Synthesis of terpenoids by Michael addition to 3-methyl-2-cyclopentenone [13].
Scheme 18: Rh-catalysed isomerisation of 3-alkyl-3-arylcyclopentanones to 1-tetralones [53].
Scheme 19: Addition reaction of phenylboronic acid to 3-methyl-2-cyclohexenone catalysed by L9/Pd(TFA)2 in wat...
Scheme 20: Micellar nanoreactor PdL10c for the synthesis of flavanones [58].
Scheme 21: Plausible catalytic cycle for the desymmetrisation of polycyclic cyclohexenediones by the addition ...
Scheme 22: Attempt to use the catalytic system L2/Pd(TFA)2 for the addition of phenylboronic acid to 3-methyl-...
Scheme 23: Ring opening of an enantioenriched tetrahydropyran-2-one derivative as alternative strategy to line...
Scheme 24: Synthesis of biologically active compounds from addition products [14-16].
Scheme 25: Chiral 1,10-phenantroline derivative L15 as ligand for the Pd-catalysed addition reactions of pheny...
Scheme 26: The Rh-catalysed addition reaction of phenylboronic acid to a 3-substituted enone [20].
Scheme 27: Underdeveloped methodologies [14,15,65-67].
Scheme 28: Flowchart for the selection of the proper catalytic system.
Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects
- Shivani Gulati,
- Stephy Elza John and
- Nagula Shankaraiah
Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71
Graphical Abstract
Figure 1: Marketed drugs with acridine moiety.
Scheme 1: Synthesis of 4-arylacridinediones.
Scheme 2: Proposed mechanism for acridinedione synthesis.
Scheme 3: Synthesis of tetrahydrodibenzoacridinones.
Scheme 4: Synthesis of naphthoacridines.
Scheme 5: Plausible mechanism for naphthoacridines.
Figure 2: Benzoazepines based potent molecules.
Scheme 6: Synthesis of azepinone.
Scheme 7: Proposed mechanism for azepinone formation.
Scheme 8: Synthesis of benzoazulenen-1-one derivatives.
Scheme 9: Proposed mechanism for benzoazulene-1-one synthesis.
Figure 3: Indole-containing pharmacologically active molecules.
Scheme 10: Synthesis of functionalized indoles.
Scheme 11: Plausible mechanism for the synthesis of functionalized indoles.
Scheme 12: Synthesis of spirooxindoles.
Scheme 13: Synthesis of substituted spirooxindoles.
Scheme 14: Plausible mechanism for the synthesis of substituted spirooxindoles.
Scheme 15: Synthesis of pyrrolidinyl spirooxindoles.
Scheme 16: Proposed mechanism for pyrrolidinyl spirooxindoles.
Figure 4: Pyran-containing biologically active molecules.
Scheme 17: Synthesis of functionalized benzopyrans.
Scheme 18: Plausible mechanism for synthesis of benzopyran.
Scheme 19: Synthesis of indoline-spiro-fused pyran derivatives.
Scheme 20: Proposed mechanism for indoline-spiro-fused pyran.
Scheme 21: Synthesis of substituted naphthopyrans.
Figure 5: Marketed drugs with pyrrole ring.
Scheme 22: Synthesis of tetra-substituted pyrroles.
Scheme 23: Mechanism for silica-supported PPA-SiO2-catalyzed pyrrole synthesis.
Scheme 24: Synthesis of pyrrolo[1,10]-phenanthrolines.
Scheme 25: Proposed mechanism for pyrrolo[1,10]-phenanthrolines.
Figure 6: Marketed drugs and molecules containing pyrimidine and pyrimidinones skeletons.
Scheme 26: MWA-MCR pyrimidinone synthesis.
Scheme 27: Two proposed mechanisms for pyrimidinone synthesis.
Scheme 28: MWA multicomponent synthesis of dihydropyrimidinones.
Scheme 29: Proposed mechanism for dihydropyrimidinones.
Figure 7: Biologically active fused pyrimidines.
Scheme 30: MWA- MCR for the synthesis of pyrrolo[2,3-d]pyrimidines.
Scheme 31: Proposed mechanism for pyrrolo[2,3-d]pyrimidines.
Scheme 32: Synthesis of substituted pyrrolo[2,3-d]pyrimidine-2,4-diones.
Scheme 33: Probable pathway for pyrrolo[2,3-d]pyrimidine-2,4-diones.
Scheme 34: Synthesis of pyridopyrimidines.
Scheme 35: Plausible mechanism for the synthesis of pyridopyrimidines.
Scheme 36: Synthesis of dihydropyridopyrimidine and dihydropyrazolopyridine.
Scheme 37: Proposed mechanism for the formation of dihydropyridopyrimidine.
Scheme 38: Synthesis of thiopyrano[4,3-d]pyrimidines.
Scheme 39: Plausible mechanism for the synthesis of thiopyrano[4,3-d]pyrimidines.
Scheme 40: Synthesis of decorated imidazopyrimidines.
Scheme 41: Proposed mechanism for imidazopyrimidine synthesis.
Figure 8: Pharmacologically active molecules containing purine bases.
Scheme 42: Synthesis of aza-adenines.
Scheme 43: Synthesis of 5-aza-7-deazapurines.
Scheme 44: Proposed mechanism for deazapurines synthesis.
Figure 9: Biologically active molecules containing pyridine moiety.
Scheme 45: Synthesis of steroidal pyridines.
Scheme 46: Proposed mechanism for steroidal pyridine.
Scheme 47: Synthesis of N-alkylated 2-pyridones.
Scheme 48: Two possible mechanisms for pyridone synthesis.
Scheme 49: Synthesis of pyridone derivatives.
Scheme 50: Postulated mechanism for synthesis of pyridone.
Figure 10: Biologically active fused pyridines.
Scheme 51: Benzimidazole-imidazo[1,2-a]pyridines synthesis.
Scheme 52: Mechanism for the synthesis of benzimidazole-imidazo[1,2-a]pyridines.
Scheme 53: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanedione derivatives.
Scheme 54: Proposed mechanism for spiro-pyridines.
Scheme 55: Functionalized macrocyclane-fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 56: Mechanism postulated for macrocyclane-fused pyrazolo[3,4-b]pyridine.
Scheme 57: Generation of pyrazolo[3,4-b]pyridines.
Scheme 58: Proposed mechanism for the synthesis of pyrazolo[3,4-b]pyridines.
Scheme 59: Proposed mechanism for the synthesis of azepinoindole.
Figure 11: Pharmaceutically important molecules with quinoline moiety.
Scheme 60: Povarov-mediated quinoline synthesis.
Scheme 61: Proposed mechanism for Povarov reaction.
Scheme 62: Synthesis of pyrazoloquinoline.
Scheme 63: Plausible mechanism for pyrazoloquinoline synthesis.
Figure 12: Quinazolinones as pharmacologically significant scaffolds.
Scheme 64: Four-component reaction for dihydroquinazolinone.
Scheme 65: Proposed mechanism for dihydroquinazolinones.
Scheme 66: Synthesis purine quinazolinone and PI3K-δ inhibitor.
Scheme 67: Synthesis of fused benzothiazolo/benzoimidazoloquinazolinones.
Scheme 68: Proposed mechanism for fused benzothiazolo/benzoimidazoloquinazolinones.
Scheme 69: On-water reaction for synthesis of thiazoloquinazolinone.
Scheme 70: Proposed mechanism for the thiazoloquinazolinone synthesis.
Scheme 71: β-Cyclodextrin-mediated synthesis of indoloquinazolinediones.
Scheme 72: Proposed mechanism for synthesis of indoloquinazolinediones.
Figure 13: Triazoles-containing marketted drugs and pharmacologically active molecules.
Scheme 73: Cu(I) DAPTA-catalyzed 1,2,3-triazole formation.
Scheme 74: Mechanism for Cu(I) DAPTA-catalyzed triazole formation.
Scheme 75: Synthesis of β-hydroxy-1,2,3-triazole.
Scheme 76: Proposed mechanism for synthesis of β-hydroxy-1,2,3-triazoles.
Scheme 77: Synthesis of bis-1,2,4-triazoles.
Scheme 78: Proposed mechanism for bis-1,2,4-triazoles synthesis.
Figure 14: Thiazole containing drugs.
Scheme 79: Synthesis of a substituted thiazole ring.
Scheme 80: Synthesis of pyrazolothiazoles.
Figure 15: Chromene containing drugs.
Scheme 81: Magnetic nanocatalyst-mediated aminochromene synthesis.
Scheme 82: Proposed mechanism for the synthesis of chromenes.
The synthesis of chiral β-naphthyl-β-sulfanyl ketones via enantioselective sulfa-Michael reaction in the presence of a bifunctional cinchona/sulfonamide organocatalyst
- Deniz Tözendemir and
- Cihangir Tanyeli
Beilstein J. Org. Chem. 2021, 17, 494–503, doi:10.3762/bjoc.17.43
- sulfa-Michael additions of thiols to chalcones with sulfonamide-type organocatalysts in the literature [30][31], in this study, a new quinine sulfonamide organocatalyst derivative was developed to catalyze the enantioselective SMA of naphthalene-1-thiol to trans-chalcones under mild conditions and with
- while the deprotonated nucleophile is oriented by the Brønsted acid moiety. The substrate scope was extended to substituted chalcones, under the optimized conditions (Table 3). The chalcone derivatives used in this work were obtained by Claisen–Schmidt condensation, using known procedures [44]. Among
- conclusion, we report the enantioselective organocatalytic sulfa-Michael addition reaction of naphthalene-1-thiol to trans-chalcones, in the presence of a new bifunctional quinine derived sulfonamide organocatalyst. The adducts obtained with moderate to excellent ee values are β-naphthyl-β-sulfanyl ketones
Graphical Abstract
Scheme 1: Synthesis of organocatalyst 5.
Figure 1: Structures of the screened organocatalysts.
Scheme 2: Proposed transition state for the SMA of 1-thionaphthol to trans-chalcones.
Figure 2: Comparison of the ee values of SMA in the presence of THF and DCM as solvent.
Synthesis of trifluoromethyl ketones by nucleophilic trifluoromethylation of esters under a fluoroform/KHMDS/triglyme system
- Yamato Fujihira,
- Yumeng Liang,
- Makoto Ono,
- Kazuki Hirano,
- Takumi Kagawa and
- Norio Shibata
Beilstein J. Org. Chem. 2021, 17, 431–438, doi:10.3762/bjoc.17.39
- compounds to trifluoromethyl carbinols because it does not require any expensive reagents nor very low-temperature conditions. Although the reaction has a broad substrate scope of embracing ketones, chalcones and aldehydes, the transformation of esters to trifluoromethyl ketones by this protocol was never
Graphical Abstract
Scheme 1: Chemistry of the CF3 anion generated from HCF3. a) Decomposition of the trifluoromethyl anion to di...
Figure 1: Trifluoromethyl ketones. a) Hydrolysis of trifluoromethyl ketones. b) Selected examples of biologic...
Scheme 2: Trifluoromethylation of esters by HCF3 by a) Russell and Roques (1998), b) Prakash and co-workers (...
Scheme 3: Substrate scope of esters 1 for trifluoromethylation by HCF3 under the optimized conditions. aDeter...
Using multiple self-sorting for switching functions in discrete multicomponent systems
- Amit Ghosh and
- Michael Schmittel
Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233
- ), cucurbit[7]uril (3), and the two chalcones 1 and 2 in aqueous solution [48]. When the hosts 3 and 4 were mixed with the trans-chalcones 1 and 2 as guests in a 1:1:1:1 ratio, instantly a statistical mixture formed displaying all four possible host–guest complexes. After the exposure to an acid, the ensuing
Graphical Abstract
Figure 1: Some selected self-sorting outcomes and their qualitative and quantitative assessment.
Figure 2: Illustration of an integrative vs a non-integrative self-sorting.
Figure 3: The pH-driven four-component 2-fold completive self-sorting based on host–guest chemistry.
Figure 4: (a) The monomers 5 and 6 and their H-bonding array. (b) The hydrogen-bonded octameric and tetrameri...
Figure 5: (a) Two new Zn4L6-type cages. (b) The encapsulation of C70 induced distinct reconstitutions within ...
Figure 6: The formation of octahedral cages (a) [Co6(10')4]12+ and (b) [Co6(11')4]12+. (c) The 2-fold complet...
Figure 7: Exchange of Ag+ for Au+ ions in poly-NHC ligand-based organometallic assemblies.
Figure 8: The reversible interconversion between the three-component rectangle [Cu4(16)2(17)2]4+ and the four...
Figure 9: a) Chemical structure of the monomer 20 with its quadruple hydrogen-bonding array and a metal-affin...
Figure 10: Communication between the nanoswitch 21 and the supramolecular assemblies [Cu4(22)2(24)2]4+ or [Cu6(...
Figure 11: (a) The chemical structures and cartoon representations of the switch 25, the decks 26 and 27, and ...
Figure 12: Double self-sorting leads to a catalytic machinery in SelfSORT-II, in which the 46 kHz-nanorotor ac...
Figure 13: ON/OFF control of a networked catalytic catch–release system.
Figure 14: A multicomponent information system for the reversible reconfiguration of switchable dual catalysis....
Figure 15: a) The chemically fueled cascaded ion translocation, monitored by distinct emission colors. b) Work...
Figure 16: Cyclic metallosupramolecular transformations.
Figure 17: Fully reversible multiple-state rearrangement of metallosupramolecular architectures depending upon...
Figure 18: The selective encapsulation and sequential release of guests in a self-sorted mixture of three tetr...
Figure 19: Two catalytic reactions are alternately controlled by a toggle nanoswitch.
Figure 20: A biped walking along a tetrahedral track and unfolding its catalytic action. Adapted with permissi...
Figure 21: A three state supramolecular AND logic gate.
Figure 22: Four-component nanorotor and its catalytic activity. Adapted with permission from (Biswas, P. K.; S...
Selective and reversible 1,3-dipolar cycloaddition of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with 1,3-diphenylprop-2-en-1-ones under microwave irradiation
- Alexander P. Molchanov,
- Mariia M. Efremova,
- Mariya A. Kryukova and
- Mikhail A. Kuznetsov
Beilstein J. Org. Chem. 2020, 16, 2679–2686, doi:10.3762/bjoc.16.218
- the hexahydropyrazolo[1,2-a]pyrazole ring, respectively, apparently through zwitterionic intermediates [28][29]. At the same time, the cycloaddition of azomethine imine to 1,3-diphenylprop-2-en-1-ones (chalcones) in IL proceeds stereo- and regioselectively giving two diastereomeric bicyclic anti
- -Michael-type cycloadducts [28]. Very recently, a catalytic enantioselective (3 + 2) cycloaddition of diazabicyclohexanes with chalcones was carried out [30]. 1,5-Diazabicyclo[3.1.0]hexanes have been employed as precursors for 1,3-dipoles not only in (3 + 2) but also in (3 + 3) cycloadditions. It was shown
- unstable intermediate azomethine imines, generated under the reaction conditions [16][20][40]. The reaction products were separated by column chromatography and their structures proved by spectral data. Because there are contradictory data on the product structures of the reaction of DABCH with chalcones
Graphical Abstract
Scheme 1: The two types of azomethine imines (AMI).
Scheme 2: Reaction of 1,5-diazabicyclo[3.1.0]hexanes 1a–d with diarylpropenones 2a–l.
Figure 1: Single-crystal X-ray structure of compound 3e.
Figure 2: Single-crystal X-ray structure of compound 3g.
Scheme 3: Control experiments.
Scheme 4: Mechanistic hypothesis for cycloaddition and cycloreversion reactions of diazabicyclohexane 1a with...
Scheme 5: Experiments on the trapping of azomethine imine, generated from pyrazolopyrazole 3g.
Recent synthesis of thietanes
- Jiaxi Xu
Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116
Graphical Abstract
Figure 1: Examples of biologically active thietane-containing molecules.
Figure 2: The diverse methods for the synthesis of thietanes.
Scheme 1: Synthesis of 1-(thietan-2-yl)ethan-1-ol (10) from 3,5-dichloropentan-2-ol (9).
Scheme 2: Synthesis of thietanose nucleosides 2,14 from 2,2-bis(bromomethyl)propane-1,3-diol (11).
Scheme 3: Synthesis of methyl 3-vinylthietane-3-carboxylate (19).
Scheme 4: Synthesis of 1,6-thiazaspiro[3.3]heptane (24).
Scheme 5: Synthesis of 6-amino-2-thiaspiro[3.3]heptane hydrochloride (28).
Scheme 6: Synthesis of optically active thietane 31 from vitamin C.
Scheme 7: Synthesis of an optically active thietane nucleoside from diethyl L-tartrate (32).
Scheme 8: Synthesis of thietane-containing spironucleoside 40 from 5-aldo-3-O-benzyl-1,2-O-isopropylidene-α-D...
Scheme 9: Synthesis of optically active 2-methylthietane-containing spironucleoside 43.
Scheme 10: Synthesis of a double-linked thietane-containing spironucleoside 48.
Scheme 11: Synthesis of two diastereomeric thietanose nucleosides via 2,4-di(benzyloxymethyl)thietane (49).
Scheme 12: Synthesis of the thietane-containing PI3k inhibitor candidate 54.
Scheme 13: Synthesis of the spirothietane 57 as the key intermediate to Nuphar sesquiterpene thioalkaloids.
Scheme 14: Synthesis of spirothietane 61 through a direct cyclic thioetherification of 3-mercaptopropan-1-ol.
Scheme 15: Synthesis of thietanes 66 from 1,3-diols 62.
Scheme 16: Synthesis of thietanylbenzimidazolone 75 from (iodomethyl)thiazolobenzimidazole 70.
Scheme 17: Synthesis of 2-oxa-6-thiaspiro[3.3]heptane (80) from bis(chloromethyl)oxetane 76 and thiourea.
Scheme 18: Synthesis of the thietane-containing glycoside, 2-O-p-toluenesulfonyl-4,6-thioanhydro-α-D-gulopyran...
Scheme 19: Synthesis of methyl 4,6-thioanhydro-α-D-glucopyranoside (89).
Scheme 20: Synthesis of thietane-fused α-D-galactopyranoside 93.
Scheme 21: Synthesis of thietane-fused α-D-gulopyranoside 100.
Scheme 22: Synthesis of 3,5-anhydro-3-thiopentofuranosides 104.
Scheme 23: Synthesis of anhydro-thiohexofuranosides 110, 112 and 113 from from 1,2:4,5-di-O-isopropylidene D-f...
Scheme 24: Synthesis of optically active thietanose nucleosides from D- and L-xyloses.
Scheme 25: Synthesis of thietane-fused nucleosides.
Scheme 26: Synthesis of 3,5-anhydro-3-thiopentofuranosides.
Scheme 27: Synthesis of 2-amino-3,5-anhydro-3-thiofuranoside 141.
Scheme 28: Synthesis of thietane-3-ols 145 from (1-chloromethyl)oxiranes 142 and hydrogen sulfide.
Scheme 29: Synthesis of thietane-3-ol 145a from chloromethyloxirane (142a).
Scheme 30: Synthesis of thietane-3-ols 145 from 2-(1-haloalkyl)oxiranes 142 and 147 with ammonium monothiocarb...
Scheme 31: Synthesis of 7-deoxy-5(20)thiapaclitaxel 154a, a thietane derivative of taxoids.
Scheme 32: Synthesis of 5(20)-thiadocetaxel 158 from 10-deacetylbaccatin III (155).
Scheme 33: Synthesis of thietane derivatives 162 as precursors for deoxythiataxoid synthesis through oxiraneme...
Scheme 34: Synthesis of 7-deoxy 5(20)-thiadocetaxel 154b.
Scheme 35: Mechanism for the formation of the thietane ring in 171 from oxiranes with vicinal leaving groups 1...
Scheme 36: Synthesis of cis-2,3-disubstituted thietane 175 from thiirane-2-methanol 172.
Scheme 37: Synthesis of a bridged thietane 183 from aziridine cyclohexyl tosylate 179 and ammonium tetrathiomo...
Scheme 38: Synthesis of thietanes via the photochemical [2 + 2] cycloaddition of thiobenzophenone 184a with va...
Scheme 39: Synthesis of spirothietanes through the photo [2 + 2] cycloaddition of cyclic thiocarbonyls with ol...
Scheme 40: Photochemical synthesis of spirothietane-thioxanthenes 210 from thioxanthenethione (208) and butatr...
Scheme 41: Synthesis of thietanes 213 from 2,4,6-tri(tert-butyl)thiobenzaldehyde (211) with substituted allene...
Scheme 42: Photochemical synthesis of spirothietanes 216 and 217 from N-methylthiophthalimide (214) with olefi...
Scheme 43: Synthesis of fused thietanes from quadricyclane with thiocarbonyl derivatives 219.
Scheme 44: Synthesis of tricyclic thietanes via the photo [2 + 2] cycloaddition of N-methyldithiosuccinimides ...
Scheme 45: Synthesis of tricyclic thietanes via the photo [2 + 2] cycloaddition of N-methylthiosuccinimide/thi...
Scheme 46: Synthesis of tricyclic thietanes via the photo [2 + 2] cycloaddition of N-alkylmonothiophthalimides...
Scheme 47: Synthesis of spirothietanes from dithiosuccinimides 223 with 2,3-dimethyl-2-butene (215a).
Scheme 48: Synthesis of thietanes 248a,b from diaryl thione 184b and ketene acetals 247a,b.
Scheme 49: Photocycloadditions of acridine-9-thiones 249 and pyridine-4(1H)-thione (250) with 2-methylacrynitr...
Scheme 50: Synthesis of thietanes via the photo [2 + 2] cycloaddition of mono-, di-, and trithiobarbiturates 2...
Scheme 51: Synthesis of spirothietanes via the photo [2 + 2] cycloaddition of 1,1,3-trimethyl-2-thioxo-1,2-dih...
Scheme 52: Synthesis of spirothietanes via the photo [2 + 2] cycloaddition of thiocoumarin 286 with olefins.
Scheme 53: Photochemical synthesis of thietanes 296–299 from semicyclic and acyclic thioimides 292–295 and 2,3...
Scheme 54: Photochemical synthesis of spirothietane 301 from 1,3,3-trimethylindoline-2-thione (300) and isobut...
Scheme 55: Synthesis of spirobenzoxazolethietanes 303 via the photo [2 + 2] cycloaddition of alkyl and aryl 2-...
Scheme 56: Synthesis of spirothietanes from tetrahydrothioxoisoquinolines 306 and 307 with olefins.
Scheme 57: Synthesis of spirothietanes from 1,3-dihydroisobenzofuran-1-thiones 311 and benzothiophene-1-thione...
Scheme 58: Synthesis of 2-triphenylsilylthietanes from phenyl triphenylsilyl thioketone (316) with electron-po...
Scheme 59: Diastereoselective synthesis of spiropyrrolidinonethietanes 320 via the photo [2 + 2] cycloaddition...
Scheme 60: Synthesis of bicyclic thietane 323 via the photo [2 + 2] cycloaddition of 2,4-dioxo-3,4-dihydropyri...
Scheme 61: Photo-induced synthesis of fused thietane-2-thiones 325 and 326 from silacyclopentadiene 324 and ca...
Scheme 62: Synthesis of highly strained tricyclic thietanes 328 via the intramolecular photo [2 + 2] cycloaddi...
Scheme 63: Synthesis of tri- and pentacyclic thietanes 330 and 332, respectively, through the intramolecular p...
Scheme 64: Synthesis of tricyclic thietanes 334 via the intramolecular photo [2 + 2] cycloaddition of N-vinylt...
Scheme 65: Synthesis of tricyclic thietanes 336 via the intramolecular photo [2 + 2] cycloaddition of N-but-3-...
Scheme 66: Synthesis of tricyclic thietanes via the intramolecular photo [2 + 2] cycloaddition of N-but-3-enyl...
Scheme 67: Synthesis of tetracyclic thietane 344 through the intramolecular photo [2 + 2] cycloaddition of N-[...
Scheme 68: Synthesis of tri- and tetracyclic thietanes 348, 350, and 351, through the intramolecular photo [2 ...
Scheme 69: Synthesis of tetracyclic fused thietane 354 via the photo [2 + 2] cycloaddition of vinyl 2-thioxo-3H...
Scheme 70: Synthesis of highly rigid thietane-fused β-lactams via the intramolecular photo [2 + 2] cycloadditi...
Scheme 71: Asymmetric synthesis of a highly rigid thietane-fused β-lactam 356a via the intramolecular photo [2...
Scheme 72: Diastereoselective synthesis of the thietane-fused β-lactams via the intramolecular photo [2 + 2] c...
Scheme 73: Asymmetric synthesis of thietane-fused β-lactams 356 via the intramolecular photo [2 + 2] cycloaddi...
Scheme 74: Synthesis of the bridged bis(trifluoromethyl)thietane from 2,2,4,4-tetrakis(trifluoromethyl)-1,3-di...
Scheme 75: Synthesis of the bridged-difluorothietane 368 from 2,2,4,4-tetrafluoro-1,3-dithietane (367) and qua...
Scheme 76: Synthesis of bis(trifluoromethyl)thietanes from 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietane (3...
Scheme 77: Synthesis of 2,2-dimethylthio-4,4-di(trifluoromethyl)thietane (378) from 2,2,4,4-tetrakis(trifluoro...
Scheme 78: Formation of bis(trifluoromethyl)thioacetone (381) through nucleophilic attack of dithietane 363 by...
Scheme 79: Synthesis of 2,2-bis(trifluoromethyl)thietanes from 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietan...
Scheme 80: Synthesis of the bridged bis(trifluoromethyl)thietane 364 from of 2,2,4,4-tetrakis(trifluoromethyl)...
Scheme 81: Synthesis of 2,4-diiminothietanes 390 from alkenimines and 4-methylbenzenesulfonyl isothiocyanate (...
Scheme 82: Synthesis of arylidene 2,4-diiminothietanes 393 starting from phosphonium ylides 391 and isothiocya...
Scheme 83: Synthesis of thietane-2-ylideneacetates 397 through a DABCO-catalyzed formal [2 + 2] cycloaddition ...
Scheme 84: Synthesis of 3-substituted thietanes 400 from (1-chloroalkyl)thiiranes 398.
Scheme 85: Synthesis of N-(thietane-3-yl)azaheterocycles 403 and 404 through reaction of chloromethylthiirane (...
Scheme 86: Synthesis of 3-sulfonamidothietanes 406 from sulfonamides and chloromethylthiirane (398a).
Scheme 87: Synthesis of N-(thietane-3-yl)isatins 408 from chloromethylthiirane (398a) and isatins 407.
Scheme 88: Synthesis of 3-(nitrophenyloxy)thietanes 410 from nitrophenols 409 and chloromethylthiirane (398a).
Scheme 89: Synthesis of N-aryl-N-(thietane-3-yl)cyanamides 412 from N-arylcyanamides 411 and chloromethylthiir...
Scheme 90: Synthesis of 1-(thietane-3-yl)pyrimidin-2,4(1H,3H)-diones 414 from chloromethylthiirane (398a) and ...
Scheme 91: Synthesis of 2,4-diiminothietanes 418 from 2-iminothiiranes 416 and isocyanoalkanes 415.
Scheme 92: Synthesis of 2-vinylthietanes 421 from thiiranes 419 and 3-chloroallyl lithium (420).
Scheme 93: Synthesis of thietanes from thiiranes 419 and trimethyloxosulfonium iodide 424.
Scheme 94: Mechanism for synthesis of thietanes 425 from thiiranes 419 and trimethyloxosulfonium iodide 424.
Scheme 95: Synthesis of functionalized thietanes from thiiranes and dimethylsulfonium acylmethylides.
Scheme 96: Mechanism for the rhodium-catalyzed synthesis of functionalized thietanes 429 from thiiranes 419 an...
Scheme 97: Synthesis of 3-iminothietanes 440 through thermal isomerization from 4,5-dihydro-1,3-oxazole-4-spir...
Scheme 98: Synthesis of thietanes 443 from 3-chloro-2-methylthiolane (441) through ring contraction.
Scheme 99: Synthesis of an optically active thietanose 447 from D-xylose involving a ring contraction.
Scheme 100: Synthesis of optically thietane 447 via the DAST-mediated ring contraction of 448.
Scheme 101: Synthesis of the optically thietane nucleoside 451 via the ring contraction of thiopentose in 450.
Scheme 102: Synthesis of spirothietane 456 from 3,3,5,5-tetramethylthiolane-2,4-dithione (452) and benzyne (453...
Scheme 103: Synthesis of thietanes 461 via photoisomerization of 2H,6H-thiin-3-ones 459.
Scheme 104: Phosphorodithioate-mediated synthesis of 1,4-diarylthietanes 465.
Scheme 105: Mechanism of the phosphorodithioate-mediated synthesis of 1,4-diarylthietanes 465.
Scheme 106: Phosphorodithioate-mediated synthesis of trisubstituted thietanes (±)-470.
Scheme 107: Mechanism on the phosphorodithioate-mediated synthesis of trisubstituted thietanes.
Scheme 108: Phosphorodithioate-mediated synthesis of thietanes (±)-475.
Scheme 109: Phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes from aldehydes 476 and acrylon...
Scheme 110: Phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes via a one-pot three-component ...
Scheme 111: Mechanism for the phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes via three-co...
Scheme 112: Phosphorodithioate-mediated synthesis of substituted 3-nitrothietanes.
Scheme 113: Mechanism on the phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes (±)-486.
Scheme 114: Asymmetric synthesis of (S)-2-phenylthietane (497).
Scheme 115: Asymmetric synthesis of optically active 2,4-diarylthietanes.
Scheme 116: Synthesis of 3-acetamidothietan-2-one 503 via the intramolecular thioesterification of 3-mercaptoal...
Scheme 117: Synthesis of 4-substituted thietan-2-one via the intramolecular thioesterification of 3-mercaptoalk...
Scheme 118: Synthesis of 4,4-disubstituted thietan-2-one 511 via the intramolecular thioesterification of the 3...
Scheme 119: Synthesis of a spirothietan-2-one 514 via the intramolecular thioesterification of 3-mercaptoalkano...
Scheme 120: Synthesis of thiatetrahydrolipstatin starting from (S)-(−)-epichlorohydrin ((S)-142a).
Scheme 121: Synthesis of 2-phenethyl-4-(propan-2-ylidene)thietane (520) from 5-bromo-6-methyl-1-phenylhept-5-en...
Scheme 122: Synthesis of 2-phenethyl-4-(propan-2-ylidene)thietane (520) directly from S-(5-bromo-6-methyl-1-phe...
Scheme 123: Synthesis of 2-alkylidenethietanes from S-(2-bromoalk-1-en-4-yl)thioacetates.
Scheme 124: Synthesis of 2-alkylidenethietanes from S-(2-bromo/chloroalk-1-en-4-yl)thiols.
Scheme 125: Synthesis of spirothietan-3-ol 548 from enone 545 and ammonium hydrosulfide.
Scheme 126: Asymmetric synthesis of the optically active thietanoside from cis-but-2-ene-1,4-diol (47).
Scheme 127: Synthesis of 2-alkylidenethietan-3-ols 557 via the fluoride-mediated cyclization of thioacylsilanes ...
Scheme 128: Synthesis of 2-iminothietanes via the reaction of propargylbenzene (558) and isothiocyanates 560 in...
Scheme 129: Synthesis of 2-benzylidenethietane 567 via the nickel complex-catalyzed electroreductive cyclizatio...
Scheme 130: Synthesis of 2-iminothietanes 569 via the photo-assisted electrocyclic reaction of N-monosubstitute...
Scheme 131: Synthesis of ethyl 3,4-diiminothietane-2-carboxylates from ethyl thioglycolate (570) and bis(imidoy...
Scheme 132: Synthesis of N-(thietan-3-yl)-α-oxoazaheterocycles from azaheterocyclethiones and chloromethyloxira...
Scheme 133: Synthesis of thietan-3-yl benzoate (590) via the nickel-catalyzed intramolecular reductive thiolati...
Scheme 134: Synthesis of 2,2-bis(trifluoromethyl)thietane from 3,3-bis(trifluoromethyl)-1,2-dithiolane.
Scheme 135: Synthesis of thietanes from enamines and sulfonyl chlorides.
Scheme 136: Synthesis of spirothietane 603 via the [2 + 3] cycloaddition of 2,2,4,4-tetramethylcyclobutane-1,3-...
Scheme 137: Synthesis of thietane (605) from 1-bromo-3-chloropropane and sulfur.
Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis
- Stephanie G. E. Amos,
- Marion Garreau,
- Luca Buzzetti and
- Jerome Waser
Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103
- -hydroxyphthalimide (NHPI, OD22, similar to the benzophenone photocatalysts OD9 and OD10) can abstract an H atom from the aldehyde substrate 20.1. The resulting acyl radical adds to the (E)-β-nitrostyrene 20.2, and the following denitrosylation affords the chalcones 20.3. Alkenyl and aryl radical ions (radical
Graphical Abstract
Figure 1: Selected examples of organic dyes. Mes-Acr+: 9-mesityl-10-methylacridinium, DCA: 9,10-dicyanoanthra...
Scheme 1: Activation modes in photocatalysis.
Scheme 2: Main strategies for the formation of C(sp3) radicals used in organophotocatalysis.
Scheme 3: Illustrative example for the photocatalytic oxidative generation of radicals from carboxylic acids:...
Scheme 4: Illustrative example for the photocatalytic reductive generation of C(sp3) radicals from redoxactiv...
Figure 2: Common substrates for the photocatalytic oxidative generation of C(sp3) radicals.
Scheme 5: Illustrative example for the photocatalytic oxidative generation of radicals from dihydropyridines ...
Scheme 6: Illustrative example for the photocatalytic oxidative generation of C(sp3) radicals from trifluorob...
Scheme 7: Illustrative example for the photocatalytic reductive generation of C(sp3) radicals from benzylic h...
Scheme 8: Illustrative example for the photocatalytic generation of C(sp3) radicals via direct HAT: the cross...
Scheme 9: Illustrative example for the photocatalytic generation of C(sp3) radicals via indirect HAT: the deu...
Scheme 10: Selected precursors for the generation of aryl radicals using organophotocatalysis.
Scheme 11: Illustrative example for the photocatalytic reductive generation of aryl radicals from aryl diazoni...
Scheme 12: Illustrative examples for the photocatalytic reductive generation of aryl radicals from haloarenes:...
Scheme 13: Illustrative example for the photocatalytic reductive generation of aryl radicals from aryl halides...
Scheme 14: Illustrative example for the photocatalytic reductive generation of aryl radicals from arylsulfonyl...
Scheme 15: Illustrative example for the reductive photocatalytic generation of aryl radicals from triaryl sulf...
Scheme 16: Main strategies towards acyl radicals used in organophotocatalysis.
Scheme 17: Illustrative example for the decarboxylative photocatalytic generation of acyl radicals from α-keto...
Scheme 18: Illustrative example for the oxidative photocatalytic generation of acyl radicals from acyl silanes...
Scheme 19: Illustrative example for the oxidative photocatalytic generation of carbamoyl radicals from 4-carba...
Scheme 20: Illustrative example of the photocatalytic HAT approach for the generation of acyl radicals from al...
Scheme 21: General reactivity of a) radical cations; b) radical anions; c) the main strategies towards aryl an...
Scheme 22: Illustrative example for the oxidative photocatalytic generation of alkene radical cations from alk...
Scheme 23: Illustrative example for the reductive photocatalytic generation of an alkene radical anion from al...
Figure 3: Structure of C–X radical anions and their neutral derivatives.
Scheme 24: Illustrative example for the photocatalytic reduction of imines and the generation of an α-amino C(...
Scheme 25: Illustrative example for the oxidative photocatalytic generation of aryl radical cations from arene...
Scheme 26: NCR classifications and generation.
Scheme 27: Illustrative example for the photocatalytic reductive generation of iminyl radicals from O-aryl oxi...
Scheme 28: Illustrative example for the photocatalytic oxidative generation of iminyl radicals from α-N-oxy ac...
Scheme 29: Illustrative example for the photocatalytic oxidative generation of iminyl radicals via an N–H bond...
Scheme 30: Illustrative example for the photocatalytic oxidative generation of amidyl radicals from Weinreb am...
Scheme 31: Illustrative example for the photocatalytic reductive generation of amidyl radicals from hydroxylam...
Scheme 32: Illustrative example for the photocatalytic reductive generation of amidyl radicals from N-aminopyr...
Scheme 33: Illustrative example for the photocatalytic oxidative generation of amidyl radicals from α-amido-ox...
Scheme 34: Illustrative example for the photocatalytic oxidative generation of aminium radicals: the N-aryltet...
Scheme 35: Illustrative example for the photocatalytic oxidative generation of nitrogen-centered radical catio...
Scheme 36: Illustrative example for the photocatalytic oxidative generation of nitrogen-centered radical catio...
Scheme 37: Illustrative example for the photocatalytic oxidative generation of hydrazonyl radical from hydrazo...
Scheme 38: Generation of O-radicals.
Scheme 39: Illustrative examples for the photocatalytic generation of O-radicals from N-alkoxypyridinium salts...
Scheme 40: Illustrative examples for the photocatalytic generation of O-radicals from alkyl hydroperoxides: th...
Scheme 41: Illustrative example for the oxidative photocatalytic generation of thiyl radicals from thiols: the...
Scheme 42: Main strategies and reagents for the generation of sulfonyl radicals used in organophotocatalysis.
Scheme 43: Illustrative example for the reductive photocatalytic generation of sulfonyl radicals from arylsulf...
Scheme 44: Illustrative example of a Cl atom abstraction strategy for the photocatalytic generation of sulfamo...
Scheme 45: Illustrative example for the oxidative photocatalytic generation of sulfonyl radicals from sulfinic...
Scheme 46: Illustrative example for the photocatalytic generation of electronically excited triplet states: th...
Scheme 47: Illustrative example for the photocatalytic generation of electronically excited triplet states: th...
The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates
- Narasimhamurthy Rajeev,
- Toreshettahally R. Swaroop,
- Ahmad I. Alrawashdeh,
- Shofiur Rahman,
- Abdullah Alodhayb,
- Seegehalli M. Anil,
- Kuppalli R. Kiran,
- Chandra,
- Paris E. Georghiou,
- Kanchugarakoppal S. Rangappa and
- Maralinganadoddi P. Sadashiva
Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18
- ], iron nanoparticle-catalyzed reactions of 2-naphthol with benzaldehyde and some of its derivatives with thiourea [22], isothiocyanato oxindoles with ketones [23], ammonium isothiocyanates with chalcones [24], and α-isothiocyanato esters with α-keto amides [25]. Among the synthetic methods available for
Graphical Abstract
Scheme 1: Synthesis of carbamothioates from xanthate esters and benzyl isocyanides.
Figure 1: Substrate scope for the synthesis of carbamothioates. Reaction conditions for methods A and B: sodi...
Figure 2: ORTEP diagram of O-benzyl (4-fluorobenzyl)carbamothioate (4c).
Figure 3: Rotamers of thionocarbamates 4 (top) and computer-minimized structures of 4c (bottom).
Scheme 2: Proposed general reaction mechanism for the formation of carbamothioates (e.g., 4a) from xanthate e...
Figure 4: Optimized geometries of the reactants, transition states, intermediates, and products of the propos...
Figure 5: Relative energies of the reactants, transition states (TS1–TS3), and intermediates (Int1–Int3) of t...
Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage
- Gagandeep Kour Reen,
- Ashok Kumar and
- Pratibha Sharma
Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165
Graphical Abstract
Figure 1: Various drugs having IP nucleus.
Figure 2: Participation percentage of various TMs for the syntheses of IPs.
Scheme 1: CuI–NaHSO4·SiO2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 2: Experimental examination of reaction conditions.
Scheme 3: One-pot tandem reaction for the synthesis of 2-haloimidazopyridines.
Scheme 4: Mechanistic scheme for the synthesis of 2-haloimidazopyridine.
Scheme 5: Copper-MOF-catalyzed three-component reaction (3-CR) for imidazo[1,2-a]pyridines.
Scheme 6: Mechanism for copper-MOF-driven synthesis.
Scheme 7: Heterogeneous synthesis via titania-supported CuCl2.
Scheme 8: Mechanism involving oxidative C–H functionalization.
Scheme 9: Heterogeneous synthesis of IPs.
Scheme 10: One-pot regiospecific synthesis of imidazo[1,2-a]pyridines.
Scheme 11: Vinyl azide as an unprecedented substrate for imidazo[1,2-a]pyridines.
Scheme 12: Radical pathway.
Scheme 13: Cu(I)-catalyzed transannulation approach for imidazo[1,5-a]pyridines.
Scheme 14: Plausible radical pathway for the synthesis of imidazo[1,5-a]pyridines.
Scheme 15: A solvent-free domino reaction for imidazo[1,2-a]pyridines.
Scheme 16: Cu-NPs-mediated synthesis of imidazo[1,2-a]pyridines.
Scheme 17: CuI-catalyzed synthesis of isoxazolylimidazo[1,2-a]pyridines.
Scheme 18: Functionalization of 4-bromo derivative via Sonogashira coupling reaction.
Scheme 19: A plausible reaction pathway.
Scheme 20: Cu(I)-catalyzed intramolecular oxidative C–H amidation reaction.
Scheme 21: One-pot synthetic reaction for imidazo[1,2-a]pyridine.
Scheme 22: Plausible reaction mechanism.
Scheme 23: Cu(OAc)2-promoted synthesis of imidazo[1,2-a]pyridines.
Scheme 24: Mechanism for aminomethylation/cycloisomerization of propiolates with imines.
Scheme 25: Three-component synthesis of imidazo[1,2-a]pyridines.
Figure 3: Scope of pyridin-2(1H)-ones and acetophenones.
Scheme 26: CuO NPS-promoted A3 coupling reaction.
Scheme 27: Cu(II)-catalyzed C–N bond formation reaction.
Scheme 28: Mechanism involving Chan–Lam/Ullmann coupling.
Scheme 29: Synthesis of formyl-substituted imidazo[1,2-a]pyridines.
Scheme 30: A tandem sp3 C–H amination reaction.
Scheme 31: Probable mechanistic approach.
Scheme 32: Dual catalytic system for imidazo[1,2-a]pyridines.
Scheme 33: Tentative mechanism.
Scheme 34: CuO/CuAl2O4/ᴅ-glucose-promoted 3-CCR.
Scheme 35: A tandem CuOx/OMS-2-based synthetic strategy.
Figure 4: Biomimetic catalytic oxidation in the presence of electron-transfer mediators (ETMs).
Scheme 36: Control experiment.
Scheme 37: Copper-catalyzed C(sp3)–H aminatin reaction.
Scheme 38: Reaction of secondary amines.
Scheme 39: Probable mechanistic pathway.
Scheme 40: Coupling reaction of α-azidoketones.
Scheme 41: Probable pathway.
Scheme 42: Probable mechanism with free energy calculations.
Scheme 43: MCR for cyanated IP synthesis.
Scheme 44: Substrate scope for the reaction.
Scheme 45: Reaction mechanism.
Scheme 46: Probable mechanistic pathway for Cu/ZnAl2O4-catalyzed reaction.
Scheme 47: Copper-catalyzed double oxidative C–H amination reaction.
Scheme 48: Application towards different coupling reactions.
Scheme 49: Reaction mechanism.
Scheme 50: Condensation–cyclization approach for the synthesis of 1,3-diarylated imidazo[1,5-a]pyridines.
Scheme 51: Optimized reaction conditions.
Scheme 52: One-pot 2-CR.
Scheme 53: One-pot 3-CR without the isolation of chalcone.
Scheme 54: Copper–Pybox-catalyzed cyclization reaction.
Scheme 55: Mechanistic pathway catalyzed by Cu–Pybox complex.
Scheme 56: Cu(II)-promoted C(sp3)-H amination reaction.
Scheme 57: Wider substrate applicability for the reaction.
Scheme 58: Plausible reaction mechanism.
Scheme 59: CuI assisted C–N cross-coupling reaction.
Scheme 60: Probable reaction mechanism involving sp3 C–H amination.
Scheme 61: One-pot MCR-catalyzed by CoFe2O4/CNT-Cu.
Scheme 62: Mechanistic pathway.
Scheme 63: Synthetic scheme for 3-nitroimidazo[1,2-a]pyridines.
Scheme 64: Plausible mechanism for CuBr-catalyzed reaction.
Scheme 65: Regioselective synthesis of halo-substituted imidazo[1,2-a]pyridines.
Scheme 66: Synthesis of 2-phenylimidazo[1,2-a]pyridines.
Scheme 67: Synthesis of diarylated compounds.
Scheme 68: CuBr2-mediated one-pot two-component oxidative coupling reaction.
Scheme 69: Decarboxylative cyclization route to synthesize 1,3-diarylimidazo[1,5-a]pyridines.
Scheme 70: Mechanistic pathway.
Scheme 71: C–H functionalization reaction of enamines to produce diversified heterocycles.
Scheme 72: A plausible mechanism.
Scheme 73: CuI-promoted aerobic oxidative cyclization reaction of ketoxime acetates and pyridines.
Scheme 74: CuI-catalyzed pathway for the formation of imidazo[1,2-a]pyridine.
Scheme 75: Mechanistic pathway.
Scheme 76: Mechanistic rationale for the synthesis of products.
Scheme 77: Copper-catalyzed synthesis of vinyloxy-IP.
Scheme 78: Regioselective product formation with propiolates.
Scheme 79: Proposed mechanism for vinyloxy-IP formation.
Scheme 80: Regioselective synthesis of 3-hetero-substituted imidazo[1,2-a]pyridines with different reaction su...
Scheme 81: Mechanistic pathway.
Scheme 82: CuI-mediated synthesis of 3-formylimidazo[1,2-a]pyridines.
Scheme 83: Radical pathway for 3-formylated IP synthesis.
Scheme 84: Pd-catalyzed urea-cyclization reaction for IPs.
Scheme 85: Pd-catalyzed one-pot-tandem amination and intramolecular amidation reaction.
Figure 5: Scope of aniline nucleophiles.
Scheme 86: Pd–Cu-catalyzed Sonogashira coupling reaction.
Scheme 87: One-pot amide coupling reaction for the synthesis of imidazo[4,5-b]pyridines.
Scheme 88: Urea cyclization reaction for the synthesis of two series of pyridines.
Scheme 89: Amidation reaction for the synthesis of imidazo[4,5-b]pyridines.
Figure 6: Amide scope.
Scheme 90: Pd NPs-catalyzed 3-component reaction for the synthesis of 2,3-diarylated IPs.
Scheme 91: Plausible mechanistic pathway for Pd NPs-catalyzed MCR.
Scheme 92: Synthesis of chromenoannulated imidazo[1,2-a]pyridines.
Scheme 93: Mechanism for the synthesis of chromeno-annulated IPs.
Scheme 94: Zinc oxide NRs-catalyzed synthesis of imidazo[1,2-a]azines/diazines.
Scheme 95: Zinc oxide-catalyzed isocyanide based GBB reaction.
Scheme 96: Reaction pathway for ZnO-catalyzed GBB reaction.
Scheme 97: Mechanistic pathway.
Scheme 98: ZnO NRs-catalyzed MCR for the synthesis of imidazo[1,2-a]azines.
Scheme 99: Ugi type GBB three-component reaction.
Scheme 100: Magnetic NPs-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 101: Regioselective synthesis of 2-alkoxyimidazo[1,2-a]pyridines catalyzed by Fe-SBA-15.
Scheme 102: Plausible mechanistic pathway for the synthesis of 2-alkoxyimidazopyridine.
Scheme 103: Iron-catalyzed synthetic approach.
Scheme 104: Iron-catalyzed aminooxygenation reaction.
Scheme 105: Mechanistic pathway.
Scheme 106: Rh(III)-catalyzed double C–H activation of 2-substituted imidazoles and alkynes.
Scheme 107: Plausible reaction mechanism.
Scheme 108: Rh(III)-catalyzed non-aromatic C(sp2)–H bond activation–functionalization for the synthesis of imid...
Scheme 109: Reactivity and selectivity of different substrates.
Scheme 110: Rh-catalyzed direct C–H alkynylation by Li et al.
Scheme 111: Suggested radical mechanism.
Scheme 112: Scandium(III)triflate-catalyzed one-pot reaction and its mechanism for the synthesis of benzimidazo...
Scheme 113: RuCl3-assisted Ugi-type Groebke–Blackburn condensation reaction.
Scheme 114: C-3 aroylation via Ru-catalyzed two-component reaction.
Scheme 115: Regioselective synthetic mechanism.
Scheme 116: La(III)-catalyzed one-pot GBB reaction.
Scheme 117: Mechanistic approach for the synthesis of imidazo[1,2-a]pyridines.
Scheme 118: Synthesis of imidazo[1,2-a]pyridine using LaMnO3 NPs under neat conditions.
Scheme 119: Mechanistic approach.
Scheme 120: One-pot 3-CR for regioselective synthesis of 2-alkoxy-3-arylimidazo[1,2-a]pyridines.
Scheme 121: Formation of two possible products under optimization of the catalysts.
Scheme 122: Mechanistic strategy for NiFe2O4-catalyzed reaction.
Scheme 123: Two-component reaction for synthesizing imidazodipyridiniums.
Scheme 124: Mechanistic scheme for the synthesis of imidazodipyridiniums.
Scheme 125: CuI-catalyzed arylation of imidazo[1,2-a]pyridines.
Scheme 126: Mechanism for arylation reaction.
Scheme 127: Cupric acetate-catalyzed double carbonylation approach.
Scheme 128: Radical mechanism for double carbonylation of IP.
Scheme 129: C–S bond formation reaction catalyzed by cupric acetate.
Scheme 130: Cupric acetate-catalyzed C-3 formylation approach.
Scheme 131: Control experiments for signifying the role of DMSO and oxygen.
Scheme 132: Mechanism pathway.
Scheme 133: Copper bromide-catalyzed CDC reaction.
Scheme 134: Extension of the substrate scope.
Scheme 135: Plausible radical pathway.
Scheme 136: Transannulation reaction for the synthesis of imidazo[1,5-a]pyridines.
Scheme 137: Plausible reaction pathway for denitrogenative transannulation.
Scheme 138: Cupric acetate-catalyzed C-3 carbonylation reaction.
Scheme 139: Plausible mechanism for regioselective C-3 carbonylation.
Scheme 140: Alkynylation reaction at C-2 of 3H-imidazo[4,5-b]pyridines.
Scheme 141: Two-way mechanism for C-2 alkynylation of 3H-imidazo[4,5-b]pyridines.
Scheme 142: Palladium-catalyzed SCCR approach.
Scheme 143: Palladium-catalyzed Suzuki coupling reaction.
Scheme 144: Reaction mechanism.
Scheme 145: A phosphine free palladium-catalyzed synthesis of C-3 arylated imidazopyridines.
Scheme 146: Palladium-mediated Buchwald–Hartwig cross-coupling reaction.
Figure 7: Structure of the ligands optimized.
Scheme 147: Palladium acetate-catalyzed direct arylation of imidazo[1,2-a]pyridines.
Scheme 148: Palladium acetate-catalyzed mechanistic pathway.
Scheme 149: Palladium acetate-catalyzed regioselective arylation reported by Liu and Zhan.
Scheme 150: Mechanism for selective C-3 arylation of IP.
Scheme 151: Pd(II)-catalyzed alkenylation reaction with styrenes.
Scheme 152: Pd(II)-catalyzed alkenylation reaction with acrylates.
Scheme 153: A two way mechanism.
Scheme 154: Double C–H activation reaction catalyzed by Pd(OAc)2.
Scheme 155: Probable mechanism.
Scheme 156: Palladium-catalyzed decarboxylative coupling.
Scheme 157: Mechanistic cycle for decarboxylative arylation reaction.
Scheme 158: Ligand-free approach for arylation of imidazo[1,2-a]pyridine-3-carboxylic acids.
Scheme 159: Mechanism for ligandless arylation reaction.
Scheme 160: NHC-Pd(II) complex assisted arylation reaction.
Scheme 161: C-3 arylation of imidazo[1,2-a]pyridines with aryl bromides catalyzed by Pd(OAc)2.
Scheme 162: Pd(II)-catalyzed C-3 arylations with aryl tosylates and mesylates.
Scheme 163: CDC reaction for the synthesis of imidazo[1,2-a]pyridines.
Scheme 164: Plausible reaction mechanism for Pd(OAc)2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 165: Pd-catalyzed C–H amination reaction.
Scheme 166: Mechanism for C–H amination reaction.
Scheme 167: One-pot synthesis for 3,6-di- or 2,3,6-tri(hetero)arylimidazo[1,2-a]pyridines.
Scheme 168: C–H/C–H cross-coupling reaction of IPs and azoles catalyzed by Pd(II).
Scheme 169: Mechanistic cycle.
Scheme 170: Rh-catalyzed C–H arylation reaction.
Scheme 171: Mechanistic pathway for C–H arylation of imidazo[1,2-a]pyridine.
Scheme 172: Rh(III)-catalyzed double C–H activation of 2-phenylimidazo[1,2-a]pyridines and alkynes.
Scheme 173: Rh(III)-catalyzed mechanistic pathway.
Scheme 174: Rh(III)-mediated oxidative coupling reaction.
Scheme 175: Reactions showing functionalization of the product obtained by the group of Kotla.
Scheme 176: Mechanism for Rh(III)-catalyzed oxidative coupling reaction.
Scheme 177: Rh(III)-catalyzed C–H activation reaction.
Scheme 178: Mechanistic cycle.
Scheme 179: Annulation reactions of 2-arylimidazo[1,2-a]pyridines and alkynes.
Scheme 180: Two-way reaction mechanism for annulations reaction.
Scheme 181: [RuCl2(p-cymene)]2-catalyzed C–C bond formation reaction.
Scheme 182: Reported reaction mechanism.
Scheme 183: Fe(III) catalyzed C-3 formylation approach.
Scheme 184: SET mechanism-catalyzed by Fe(III).
Scheme 185: Ni(dpp)Cl2-catalyzed KTC coupling.
Scheme 186: Pd-catalyzed SM coupling.
Scheme 187: Vanadium-catalyzed coupling of IP and NMO.
Scheme 188: Mechanistic cycle.
Scheme 189: Selective C3/C5–H bond functionalizations by mono and bimetallic systems.
Scheme 190: rGO-Ni@Pd-catalyzed C–H bond arylation of imidazo[1,2-a]pyridine.
Scheme 191: Mechanistic pathway for heterogeneously catalyzed arylation reaction.
Scheme 192: Zinc triflate-catalyzed coupling reaction of substituted propargyl alcohols.
First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones
- Grzegorz Mlostoń,
- Katarzyna Urbaniak,
- Paweł Urbaniak,
- Anna Marko,
- Anthony Linden and
- Heinz Heimgartner
Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156
- 1,4-benzoquinone, 1,4-naphthoquinone, and 1,4-anthraquinone were investigated as a route to novel 4H-thiochromene-5,8-dione derivatives. Results and Discussion Aryl and hetary lthiochalcones 1a–d are easily obtained by treatment of the corresponding chalcones with Lawesson′s reagent in THF solution
Graphical Abstract
Scheme 1: Reactions of aryl/hetarylthiochalcones 1a–d with 1,4-naphthoquinone (2b).
Scheme 2: Reactions of thiochalcones 1a–d with 1,4-anthraquinones 2c and 2d.
Figure 1: ORTEP plot [29] of the molecular structure of 4k showing the major conformation of the disordered thiop...
Figure 2: Products of the reactions of thiochalcones 1a and 1b with 1,4-benzoquinone (2a) and of 1a with mena...
5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines
- Ranjana Aggarwal and
- Suresh Kumar
Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15
- index) = 3999, which were better than the drugs NVP (nevirapine) (EC50 = 0.17 μM) and DLV (delavirdine) (EC50 = 0.16 μM). Kaswan et al. [103] reported the reaction of 5-aminopyrazoles 16/126 with chalcones 156 in DMF in the presence of inorganic base KOH for the synthesis of 5,7-diarylpyrazolo[1,5-a
- ]pyrimidines 157. Chalcones 156 with electron-withdrawing group like nitro, cyano on para-position of aryl or heteroaryl ring and 2-hydroxyphenyl group resulted in lower yields as compared to chalcones with electron-donating groups (Scheme 44). Chobe et al. [104] reported the reaction of 3,5-diamino-4
Graphical Abstract
Figure 1: Selected examples of drugs with fused pyrazole rings.
Figure 2: Typical structures of some fused pyrazoloazines from 5-aminopyrazoles.
Scheme 1: Regiospecific synthesis of 4 and 6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridines.
Scheme 2: Synthesis of pyrazolo[3,4-b]pyridine-6-carboxylates.
Scheme 3: Synthesis of 1,4,6-triaryl-1H-pyrazolo[3,4-b]pyridines with ionic liquid .
Scheme 4: Synthesis of coumarin-based isomeric tetracyclic pyrazolo[3,4-b]pyridines.
Scheme 5: Synthesis of 6-substituted pyrazolo[3,4-b]pyridines under Heck conditions.
Scheme 6: Microwave-assisted palladium-catalyzed synthesis of pyrazolo[3,4-b]pyridines.
Scheme 7: Acid-catalyzed synthesis of pyrazolo[3,4-b]pyridines via enaminones.
Scheme 8: Synthesis of pyrazolo[3,4-b]pyridines via aza-Diels–Alder reaction.
Scheme 9: Synthesis of macrocyclane fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 10: Three-component synthesis of 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine derivatives.
Scheme 11: Ultrasonicated synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones.
Scheme 12: Synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine] derivatives under conventional heating co...
Scheme 13: Nanoparticle-catalyzed synthesis of pyrazolo[3,4-b]pyridine-spiroindolinones.
Scheme 14: Microwave-assisted multicomponent synthesis of spiropyrazolo[3,4-b]pyridines.
Scheme 15: Unexpected synthesis of naphthoic acid-substituted pyrazolo[3,4-b]pyridines.
Scheme 16: Multicomponent synthesis of variously substituted pyrazolo[3,4-b]pyridine derivatives.
Scheme 17: Three-component synthesis of 4,7-dihydropyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]pyridines.
Scheme 18: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanediones.
Scheme 19: Ultrasound-mediated three-component synthesis of pyrazolo[3,4-b]pyridines.
Scheme 20: Multicomponent synthesis of 4-aryl-3-methyl-1-phenyl-4,6,8,9-tetrahydropyrazolo [3,4-b]thiopyrano[4...
Scheme 21: Synthesis of 2,3-dihydrochromeno[4,3-d]pyrazolo[3,4-b]pyridine-1,6-diones.
Scheme 22: FeCl3-catalyzed synthesis of o-hydroxyphenylpyrazolo[3,4-b]pyridine derivatives.
Scheme 23: Ionic liquid-mediated synthesis of pyrazolo[3,4-b]pyridines.
Scheme 24: Microwave-assisted synthesis of pyrazolo[3,4-b]pyridines.
Scheme 25: Multicomponent synthesis of pyrazolo[3,4-b]pyridine-5-carbonitriles.
Scheme 26: Unusual domino synthesis of 4,7-dihydropyrazolo[3,4-b]pyridine-5-nitriles.
Scheme 27: Synthesis of 4,5,6,7-tetrahydro-4H-pyrazolo[3,4-b]pyridines under conventional heating and ultrasou...
Scheme 28: L-Proline-catalyzed synthesis of of pyrazolo[3,4-b]pyridine.
Scheme 29: Microwave-assisted synthesis of 5-aminoarylpyrazolo[3,4-b]pyridines.
Scheme 30: Microwave-assisted multi-component synthesis of pyrazolo[3,4-e]indolizines.
Scheme 31: Synthesis of fluoropropynyl and fluoroalkyl substituted pyrazolo[1,5-a]pyrimidine.
Scheme 32: Acid-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine derivatives.
Scheme 33: Chemoselective and regiospecific synthesis of 2-(3-methylpyrazol-1’-yl)-5-methylpyrazolo[1,5-a]pyri...
Scheme 34: Regioselective synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 35: Microwave-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidine carboxylates.
Scheme 36: Microwave and ultrasound-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 37: Base-catalyzed unprecedented synthesis of pyrazolo[1,5-a]pyrimidines via C–C bond cleavage.
Scheme 38: Synthesis of aminobenzothiazole/piperazine linked pyrazolo[1,5-a]pyrimidines.
Scheme 39: Synthesis of aminoalkylpyrazolo[1,5-a]pyrimidine-7-amines.
Scheme 40: Synthesis of pyrazolo[1,5-a]pyrimidines from condensation of 5-aminopyrazole 126 and ethyl acetoace...
Scheme 41: Synthesis of 7-aminopyrazolo[1,5-a]pyrimidines.
Scheme 42: Unexpected synthesis of 7-aminopyrazolo[1,5-a]pyrimidines under solvent free and solvent-mediated c...
Scheme 43: Synthesis of N-(4-aminophenyl)-7-aryloxypyrazolo[1,5-a]pyrimidin-5-amines.
Scheme 44: Base-catalyzed synthesis of 5,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 45: Synthesis of 6,7-dihydropyrazolo[1,5-a]pyrimidines in PEG-400.
Scheme 46: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine-3-carboxamides.
Scheme 47: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine derivatives under conventional heating and micro...
Scheme 48: Synthesis of N-aroylpyrazolo[1,5-a]pyrimidine-5-amines.
Scheme 49: Regioselective synthesis of ethyl pyrazolo[1,5-a]pyrimidine-7-carboxylate.
Scheme 50: Sodium methoxide-catalyzed synthesis of 3-cyano-6,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 51: Synthesis of various pyrazolo[3,4-d]pyrimidine derivatives.
Scheme 52: Synthesis of hydrazinopyrazolo[3,4-d]pyrimidine derivatives.
Scheme 53: Synthesis of N-arylidinepyrazolo[3,4-d]pyrimidin-5-amines.
Scheme 54: Synthesis of pyrazolo[3,4-d]pyrimidinyl-4-amines.
Scheme 55: Iodine-catalyzed synthesis of pyrazolo[3,4-d]pyrimidinones.
Scheme 56: Synthesis of ethyl 6-amino-2H-pyrazolo[3,4-d]pyrimidine-4-carboxylate.
Scheme 57: Synthesis of 4-substituted-(3,6-dihydropyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidines.
Scheme 58: Synthesis of 1-(2,4-dichlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl carboxamides.
Scheme 59: Synthesis of 5-(1,3,4-thidiazol-2-yl)pyrazolo[3,4-d]pyrimidine.
Scheme 60: One pot POCl3-catalyzed synthesis of 1-arylpyrazolo[3,4-d]pyrimidin-4-ones.
Scheme 61: Synthesis of 4-amino-N1,C3-dialkylpyrazolo[3,4-d]pyrimidines under Suzuki conditions.
Scheme 62: Microwave-assisted synthesis of pyrazolo[3,4-b]pyrazines.
Scheme 63: Synthesis and derivatization of pyrazolo[3,4-b]pyrazine-5-carbonitriles.
Scheme 64: Synthesis of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones.
Scheme 65: Synthesis of 2,3-dihydropyrazolo[1,5-a][1,3,5]triazin-4(1H)-one.
Scheme 66: Synthesis of pyrazolo[1,5-a][1,3,5]triazine-8-carboxylic acid ethyl ester.
Scheme 67: Microwave-assisted synthesis of 4,7-dihetarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 68: Alternative synthetic route to 4,7-diheteroarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 69: Synthesis of 4-aryl-2-ethylthio-7-methylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 70: Microwave-assisted synthesis of 4-aminopyrazolo[1,5-a][1,3,5]triazine.
Scheme 71: Synthesis of pyrazolo[3,4-d][1,2,3]triazines from pyrazol-5-yl diazonium salts.
Scheme 72: Synthesis of 2,5-dihydropyrazolo[3,4-e][1,2,4]triazines.
Scheme 73: Synthesis of pyrazolo[5,1-c][1,2,4]triazines via diazopyrazolylenaminones.
Scheme 74: Synthesis of pyrazolo[5,1-c][1,2,4]triazines in presence of sodium acetate.
Scheme 75: Synthesis of various 7-diazopyrazolo[5,1-c][1,2,4]triazine derivatives.
Scheme 76: One pot synthesis of pyrazolo[5,1-c][1,2,4]triazines.
Scheme 77: Synthesis of 4-amino-3,7,8-trinitropyrazolo-[5,1-c][1,2,4]triazines.
Scheme 78: Synthesis of tricyclic pyrazolo[5,1-c][1,2,4]triazines by azocoupling reaction.
Mechanochemical synthesis of small organic molecules
- Tapas Kumar Achar,
- Anima Bose and
- Prasenjit Mal
Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186
- bases like NaOH, KOH, NaOEt etc. have been used as catalyst for the Michael addition of 1,3-dicarbonyl compounds to α,β-unsaturated ketones. In 2004, Wang and co-workers first reported a mechanochemical Michael reaction of 1,3-dicarbonyl compounds with chalcones and azachalcones using the mild base
- and co-workers reported bromination of phenol derivatives, chalcones, 1,3-dicarbonyl compounds using NaBr as bromine source and oxone as oxidant under ball-milling conditions [96]. Within 1 h they could isolate more than 90% of mono or poly-brominated products of phenol and 1,3-dicarbonyl compounds
Graphical Abstract
Scheme 1: Mechanochemical aldol condensation reactions [48].
Scheme 2: Enantioselective organocatalyzed aldol reactions under mechanomilling. a) Based on binam-(S)-prolin...
Scheme 3: Mechanochemical Michael reaction [51].
Scheme 4: Mechanochemical organocatalytic asymmetric Michael reaction [52].
Scheme 5: Mechanochemical Morita–Baylis–Hillman (MBH) reaction [53].
Scheme 6: Mechanochemical Wittig reactions [55].
Scheme 7: Mechanochemical Suzuki reaction [56].
Scheme 8: Mechanochemical Suzuki–Miyaura coupling by LAG [57].
Scheme 9: Mechanochemical Heck reaction [59].
Scheme 10: a) Sonogashira coupling under milling conditions. b) The representative example of a double Sonogas...
Scheme 11: Copper-catalyzed CDC reaction under mechanomilling [67].
Scheme 12: Asymmetric alkynylation of prochiral sp3 C–H bonds via CDC [68].
Scheme 13: Fe(III)-catalyzed CDC coupling of 3-benzylindoles [69].
Scheme 14: Mechanochemical synthesis of 3-vinylindoles and β,β-diindolylpropionates [70].
Scheme 15: Mechanochemical C–N bond construction using anilines and arylboronic acids [78].
Scheme 16: Mechanochemical amidation reaction from aromatic aldehydes and N-chloramine [79].
Scheme 17: Mechanochemical CDC between benzaldehydes and benzyl amines [81].
Scheme 18: Mechanochemical protection of -NH2 and -COOH group of amino acids [85].
Scheme 19: Mechanochemical Ritter reaction [87].
Scheme 20: Mechanochemical synthesis of dialkyl carbonates [90].
Scheme 21: Mechanochemical transesterification reaction using basic Al2O3 [91].
Scheme 22: Mechanochemical carbamate synthesis [92].
Scheme 23: Mechanochemical bromination reaction using NaBr and oxone [96].
Scheme 24: Mechanochemical aryl halogenation reactions using NaX and oxone [97].
Scheme 25: Mechanochemical halogenation reaction of electron-rich arenes [88,98].
Scheme 26: Mechanochemical aryl halogenation reaction using trihaloisocyanuric acids [100].
Scheme 27: Mechanochemical fluorination reaction by LAG method [102].
Scheme 28: Mechanochemical Ugi reaction [116].
Scheme 29: Mechanochemical Passerine reaction [116].
Scheme 30: Mechanochemical synthesis of α-aminonitriles [120].
Scheme 31: Mechanochemical Hantzsch pyrrole synthesis [121].
Scheme 32: Mechanochemical Biginelli reaction by subcomponent synthesis approach [133].
Scheme 33: Mechanochemical asymmetric multicomponent reaction[134].
Scheme 34: Mechanochemical Paal–Knorr pyrrole synthesis [142].
Scheme 35: Mechanochemical synthesis of benzothiazole using ZnO nano particles [146].
Scheme 36: Mechanochemical synthesis of 1,2-di-substituted benzimidazoles [149].
Scheme 37: Mechanochemical click reaction using an alumina-supported Cu-catalyst [152].
Scheme 38: Mechanochemical click reaction using copper vial [155].
Scheme 39: Mechanochemical indole synthesis [157].
Scheme 40: Mechanochemical synthesis of chromene [158].
Scheme 41: Mechanochemical synthesis of azacenes [169].
Scheme 42: Mechanochemical oxidative C-P bond formation [170].
Scheme 43: Mechanochemical C–chalcogen bond formation [171].
Scheme 44: Solvent-free synthesis of an organometallic complex.
Scheme 45: Selective examples of mechano-synthesis of organometallic complexes. a) Halogenation reaction of Re...
Scheme 46: Mechanochemical activation of C–H bond of unsymmetrical azobenzene [178].
Scheme 47: Mechanochemical synthesis of organometallic pincer complex [179].
Scheme 48: Mechanochemical synthesis of tris(allyl)aluminum complex [180].
Scheme 49: Mechanochemical Ru-catalyzed olefin metathesis reaction [181].
Scheme 50: Rhodium(III)-catalyzed C–H bond functionalization under mechanochemical conditions [182].
Scheme 51: Mechanochemical Csp2–H bond amidation using Ir(III) catalyst [183].
Scheme 52: Mechanochemical Rh-catalyzed Csp2–X bond formation [184].
Scheme 53: Mechanochemical Pd-catalyzed C–H activation [185].
Scheme 54: Mechanochemical Csp2–H bond amidation using Rh catalyst.
Scheme 55: Mechanochemical synthesis of indoles using Rh catalyst [187].
Scheme 56: Mizoroki–Heck reaction of aminoacrylates with aryl halide in a ball-mill [58].
Scheme 57: IBX under mechanomilling conditions [8].
Scheme 58: Thiocarbamoylation of anilines; trapping of reactive aryl-N-thiocarbamoylbenzotriazole intermediate...
New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties
- Daria G. Selivanova,
- Alexei A. Gorbunov,
- Olga A. Mayorova,
- Alexander N. Vasyanin,
- Igor V. Lunegov,
- Elena V. Shklyaeva and
- Georgii G. Abashev
Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158
- ethanolic media resulted in the formation of 1,3-diarylsubstituted prop-2-en-1-ones 6a,b [23]. Cyclization of chalcones 6a,b with guanidine sulfate followed by oxidation with hydrogen peroxide gave rise to 2-amino-4,6-disubstituted pyrimidines 7a,b [24]. 2-(1H-Pyrrol-1-yl)pyrimidines 8a,b were synthesized
- replacement of the solvents by more polar ones results in hypsochromic shifts. The correlation between Kamlet–Taft π* parameters [29] and the absorption or emission maxima wavelength is clearly demonstrated by graphs presented in Figure 4. More detailed spectral data of chalcones 6a,b and 2-aminopyrimidines
- ). Correlation between Kamlet–Taft π* parameters [29] and the absorption and emission maxima wavelength of chalcones 6a,b (a) and 2-aminopyrimidines 7a,b (b) in the series of solvents. Comparison of UV–vis absorption spectra of 2-amino-4,6-di(4-bromophenyl)pyrimidine and 2-amino-4-[4-(9H-carbazol-9-yl)phenyl]-6
Graphical Abstract
Scheme 1: Synthesis of 9-[ω-(methoxyphenoxy)alkyl]-9H-carbazoles 1a,b.
Scheme 2: Synthesis of 9-[ω-(4-methoxyphenoxy)alkyl]-9H-carbazole-3-carbaldehydes 2a,b and 1-(5-arylthiophen-...
Scheme 3: Synthesis of quadrupolar chromophores 6a,b−8a,b.
Figure 1: Comparison of UV–vis absorption and fluorescence spectra of compounds 2a–5a (a) and 2b–5b (b) in CH...
Figure 2: Comparison of UV–vis absorption and fluorescence spectra of compounds 6a (a, b), 6b (c, d) in vario...
Figure 3: Comparison of UV–vis absorption and fluorescence spectra of compounds 7a (a, b) and 7b (c, d) in va...
Figure 4: Correlation between Kamlet–Taft π* parameters [29] and the absorption and emission maxima wavelength of...
Figure 5: Comparison of UV–vis absorption spectra of 2-amino-4,6-di(4-bromophenyl)pyrimidine and 2-amino-4-[4...
Figure 6: UV–vis absorption and fluorescence spectra of compounds 8a (a), 8b ( b) in CHCl3 (c = 10−4 mol L−1)....
Figure 7: Cyclic voltammograms of compounds 2b (a), 5b (b); WE – carbon-pyroceramic electrode, 10 cycles, Et4...
Figure 8: Cyclic voltammograms of compounds 6b (a), 7b (b), 8b (с); WE – carbon-pyroceramic electrode, 10 cyc...
Synthesis of 1-indanones with a broad range of biological activity
- Marika Turek,
- Dorota Szczęsna,
- Marek Koprowski and
- Piotr Bałczewski
Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48
- quaternary center with high diastereoselectivity as a consequence of the Stetter–Aldol–Aldol (SAA) reaction sequence. The Stetter–Aldol–Aldol conversion of the phthaldialdehyde derivatives 75 and o-formyl substituted chalcones 76 using the thiazole based carbene 78 as a precatalyst allowed to obtain spiro
- 2-bromo-6-methoxy-3-phenyl-1-indanone (130, Scheme 41). An efficient microwave-assisted synthesis of 1-indanones 132a–s related to combretastatin A-4 has been proposed by Lawrence et al. [68]. Two of the indanones were obtained via a Nazarov cyclization of chalcones 131 without using microwaves, in
- carried out in the presence of an iridium catalyst and antimony hexafluoride (AgSbF6) under mild conditions. The starting chalcones were almost completely converted into 1-indanones 138–142 and isolated in very good yields. Our research group synthesized 3-aryl-1-indanones 148 and previously unknown 3
Graphical Abstract
Figure 1: Biologically active 1-indanones and their structural analogues.
Figure 2: Number of papers about (a) 1-indanones, (b) synthesis of 1-indanones.
Scheme 1: Synthesis of 1-indanone (2) from hydrocinnamic acid (1).
Scheme 2: Synthesis of 1-indanone (2) from 3-(2-bromophenyl)propionic acid (3).
Scheme 3: Synthesis of 1-indanones 5 from 3-arylpropionic acids 4.
Scheme 4: Synthesis of kinamycin (9a) and methylkinamycin C (9b).
Scheme 5: Synthesis of trifluoromethyl-substituted arylpropionic acids 12, 1-indanones 13 and dihydrocoumarin...
Scheme 6: Synthesis of 1-indanones 16 from benzoic acids 15.
Scheme 7: Synthesis of 1-indanones 18 from arylpropionic and 3-arylacrylic acids 17.
Scheme 8: The NbCl5-induced one-step synthesis of 1-indanones 22.
Scheme 9: Synthesis of biologically active 1-indanone derivatives 26.
Scheme 10: Synthesis of enantiomerically pure indatraline ((−)-29).
Scheme 11: Synthesis of 1-indanone (2) from the acyl chloride 30.
Scheme 12: Synthesis of the mechanism-based inhibitors 33 of coelenterazine.
Scheme 13: Synthesis of the indane 2-imidazole derivative 37.
Scheme 14: Synthesis of fluorinated PAHs 41.
Scheme 15: Synthesis of 1-indanones 43 via transition metal complexes-catalyzed carbonylative cyclization of m...
Scheme 16: Synthesis of 6-methyl-1-indanone (46).
Scheme 17: Synthesis of 1-indanone (2) from ester 48.
Scheme 18: Synthesis of benzopyronaphthoquinone 51 from the spiro-1-indanone 50.
Scheme 19: Synthesis of the selective endothelin A receptor antagonist 55.
Scheme 20: Synthesis of 1-indanones 60 from methyl vinyl ketone (57).
Scheme 21: Synthesis of 1-indanones 64 from diethyl phthalate 61.
Scheme 22: Synthesis of 1-indanone derivatives 66 from various Meldrum’s acids 65.
Scheme 23: Synthesis of halo 1-indanones 69.
Scheme 24: Synthesis of substituted 1-indanones 71.
Scheme 25: Synthesis of spiro- and fused 1-indanones 73 and 74.
Scheme 26: Synthesis of spiro-1,3-indanodiones 77.
Scheme 27: Mechanistic pathway for the NHC-catalyzed Stetter–Aldol–Michael reaction.
Scheme 28: Synthesis of 2-benzylidene-1-indanone derivatives 88a–d.
Scheme 29: Synthesis of 1-indanone derivatives 90a–i.
Scheme 30: Synthesis of 1-indanones 96 from o-bromobenzaldehydes 93 and alkynes 94.
Scheme 31: Synthesis of 3-hydroxy-1-indanones 99.
Scheme 32: Photochemical preparation of 1-indanones 103 from ketones 100.
Scheme 33: Synthesis of chiral 3-aryl-1-indanones 107.
Scheme 34: Photochemical isomerization of 2-methylbenzil 108.
Scheme 35: Synthesis of 2-hydroxy-1-indanones 111a–c.
Scheme 36: Synthesis of 1-indanone derivatives 113 and 114 from η6-1,2-dioxobenzocyclobutene complex 112.
Scheme 37: Synthesis of nakiterpiosin (117).
Scheme 38: Synthesis of 2-alkyl-1-indanones 120.
Scheme 39: Synthesis of fluorine-containing 1-indanone derivatives 123.
Scheme 40: Synthesis of 2-benzylidene and 2-benzyl-1-indanones 126, 127 from the chalcone 124.
Scheme 41: Synthesis of 2-bromo-6-methoxy-3-phenyl-1-indanone (130).
Scheme 42: Synthesis of combretastatin A-4-like indanones 132a–s.
Figure 3: Chemical structures of investigated dienones 133 and synthesized cyclic products 134–137.
Figure 4: Chemical structures of 1-indanones and their heteroatom analogues 138–142.
Scheme 43: Synthesis of 2-phosphorylated and 2-non-phosphorylated 1-indanones 147 and 148 from β-ketophosphona...
Scheme 44: Photochemical synthesis of 1-indanone derivatives 150, 153a, 153b.
Scheme 45: Synthesis of polysubstituted-1-indanones 155, 157.
Scheme 46: Synthesis of 1-indanones 159a–g from α-arylpropargyl alcohols 158 using RhCl(PPh3)3 as a catalyst.
Scheme 47: Synthesis of optically active 1-indanones 162 via the asymmetric Rh-catalyzed isomerization of race...
Scheme 48: Mechanism of the Rh-catalyzed isomerization of α-arylpropargyl alcohols 161 to 1-indanones 162.
Figure 5: Chemical structure of abicoviromycin (168) and its new benzo derivative 169.
Scheme 49: Synthesis of racemic benzoabicoviromycin 172.
Scheme 50: Synthesis of [14C]indene 176.
Scheme 51: Synthesis of indanone derivatives 178–180.
Scheme 52: Synthesis of racemic pterosin A 186.
Scheme 53: Synthesis of trans-2,3-disubstituted 1-indanones 189.
Scheme 54: Synthesis of 3-aryl-1-indanone derivatives 192.
Scheme 55: Synthesis of 1-indanone derivatives 194 from 3-(2-iodoaryl)propanonitriles 193.
Scheme 56: Synthesis of 1-indanones 200–204 by cyclization of aromatic nitriles.
Scheme 57: Synthesis of 1,1’-spirobi[indan-3,3’-dione] derivative 208.
Scheme 58: Total synthesis of atipamezole analogues 211.
Scheme 59: Synthesis of 3-[4-(1-piperidinoethoxy)phenyl]spiro[indene-1,1’-indan]-5,5’-diol hydrochloride 216.
Scheme 60: Synthesis of 3-arylindan-1-ones 219.
Scheme 61: Synthesis of 2-hydroxy-1-indanones 222.
Scheme 62: Synthesis of the 1-indanone 224 from the THP/MOM protected chalcone epoxide 223.
Scheme 63: Synthesis of 1-indanones 227 from γ,δ-epoxy ketones 226.
Scheme 64: Synthesis of 2-hydroxy-2-methylindanone (230).
Scheme 65: Synthesis of 1-indanone derivatives 234 from cyclopropanol derivatives 233.
Scheme 66: Synthesis of substituted 1-indanone derivatives 237.
Scheme 67: Synthesis of 7-methyl substituted 1-indanone 241 from 1,3-pentadiene (238) and 2-cyclopentenone (239...
Scheme 68: Synthesis of disubstituted 1-indanone 246 from the siloxydiene 244 and 2-cyclopentenone 239.
Scheme 69: Synthesis of 5-hydroxy-1-indanone (250) via the Diels–Alder reaction of 1,3-diene 248 with sulfoxid...
Scheme 70: Synthesis of halogenated 1-indanones 253a and 253b.
Scheme 71: Synthesis of 1-indanones 257 and 258 from 2-bromocyclopentenones 254.
Scheme 72: Synthesis of 1-indanone 261 from 2-bromo-4-acetoxy-2-cyclopenten-1-one (260) and 1,2-dihydro-4-viny...
Scheme 73: Synthesis of 1-indanone 265 from 1,2-dihydro-7-methoxy-4-vinylnaphthalene (262) and bromo-substitut...
Scheme 74: Synthesis of 1-indanone 268 from dihydro-3-vinylphenanthrene 266 and 4-acetoxy-2-cyclopenten-1-one (...
Scheme 75: Synthesis of 1-indanone 271 from phenylselenyl-substituted cyclopentenone 268.
Scheme 76: Synthesis of 1-indanone 272 from the trienone 270.
Scheme 77: Synthesis of the 1-indanone 276 from the aldehyde 273.
Scheme 78: Synthesis of 1-indanones 278 and 279.
Scheme 79: Synthesis of 1-indanone 285 from octa-1,7-diyne (282) and cyclopentenone 239.
Scheme 80: Synthesis of benz[f]indan-1-one (287) from cyclopentenone 239 and o-bis(dibromomethyl)benzene (286)....
Scheme 81: Synthesis of 3-methyl-substituted benz[f]indan-1-one 291 from o-bis(dibromomethyl)benzene (286) and...
Scheme 82: Synthesis of benz[f]indan-1-one (295) from the anthracene epidioxide 292.
Scheme 83: Synthesis of 1-indanone 299 from homophthalic anhydride 298 and cyclopentynone 297.
Scheme 84: Synthesis of cyano-substituted 1-indanone derivative 301 from 2-cyanomethylbenzaldehyde (300) and c...
Scheme 85: Synthesis of 1-indanone derivatives 303–305 from ketene dithioacetals 302.
Scheme 86: Synthesis of 1-indanones 309–316.
Scheme 87: Mechanism of the hexadehydro-Diels–Alder (HDDA) reaction.
Scheme 88: Synthesis of 1-indenone 318 and 1-indanones 320 and 321 from tetraynes 317 and 319.
Scheme 89: Synthesis of 1-indanone 320 from the triyn 319.
Scheme 90: Synthesis 1-indanone 328 from 2-methylfuran 324.
Scheme 91: Synthesis of 1-indanones 330 and 331 from furans 329.
Scheme 92: Synthesis of 1-indanone 333 from the cycloadduct 332.
Scheme 93: Synthesis of (S)-3-arylindan-1-ones 335.
Scheme 94: Synthesis of (R)-2-acetoxy-1-indanone 338.
Figure 6: Chemical structures of obtained cyclopenta[α]phenanthrenes 339.
Scheme 95: Synthesis of the benzoindanone 343 from arylacetaldehyde 340 with 1-trimethylsilyloxycyclopentene (...
Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics
- Forrest S. Etheridge,
- Roshan J. Fernando,
- Sandra Pejić,
- Matthias Zeller and
- Geneviève Sauvé
Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182
- fluorine at the proximal or distal phenyl positions (L1-ADP and L2-ADP) were synthesized in a similar fashion with the respective fluorinated chalcones (Scheme 1). In this case, the nitro intermediates of the fluorinated chalcones could not be isolated as a solid powder, so the synthesis was carried
Graphical Abstract
Figure 1: a) Azadipyrromethene ligand labeling positioning; b and c) chelates; d) estimated HOMO/LUMO energy ...
Figure 2: Chemical structures of the fluorinated ADP derivatives of WS3 explored in the study.
Scheme 1: Generic synthetic scheme for fluorinated free ligands, where L# corresponds to the desired ligand n...
Scheme 2: Generic chelation scheme yielding WS3-based BF2+ and zinc(II) complexes.
Figure 3: TGA spectra for the zinc(II) complexes.
Figure 4: Molar absorptivities in chloroform solutions of a) zinc(II) chelates b) BF2+ chelates.
Figure 5: Normalized absorbance from spun-coat chloroform solution on microscope glass of a) zinc(II) chelate...
Figure 6: Cyclic voltamograms of zinc(II) chelates in 0.1 M TBAPF6 dichloromethane solution with Fc/Fc+ as an...
Figure 7: Cyclic voltamograms of BF2+ chelates in 0.1 M TBAPF6 dichloromethane solution with Fc/Fc+ as an int...
Figure 8: Estimated HOMO and LUMO energy levels obtained by cyclic voltammetry from the E1/2 values in dichlo...
Figure 9: ORTEP drawing of Zn(L2)2 with ellipsoids drawn at the 50% probability level and a partial labeling ...
Figure 10: ORTEP drawing of Zn(L2)2 with ellipsoids drawn at the 50% probability level and a partial labeling ...
Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines
- Adrian E. Ion,
- Liliana Cristian,
- Mariana Voicescu,
- Masroor Bangesh,
- Augustin M. Madalan,
- Daniela Bala,
- Constantin Mihailciuc and
- Simona Nica
Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171
- chemical manner, by grinding neat starting materials without the use of classical organic solvents [26]. The α,β-unsaturated ketone was formed in good yields, 72% for 2a and 70% for 2b, respectively using NaOH as base. The azulenyl-substituted chalcones are stable at room temperature for months, whereas at
- high temperature and pressure, they decompose very rapidly. Alternatively, the chalcones 2 can be isolated following the conventional synthetic route, namely the reaction of equimolar amounts of the azulene-carbaldehyde with 2-acetylpyridine in ethanol, at room temperature or, by microwave irradiation
Graphical Abstract
Scheme 1: Synthesis of 4′-azulenyl substituted terpyridines.
Figure 1: Molecular structure and numbering scheme of 4′-(1-azulenyl)-2,2′:6′,2″-terpyridine (4a, left) and 4...
Figure 2: Packing diagram for 4a showing the π–π stacking and CH–π interactions between the pyridine rings an...
Figure 3: Packing diagram for 4b showing the π–π stacking between the pyridine rings. Hydrogen atoms are omit...
Figure 4: Absorption spectra of the azulene-containing terpyridine, 4a and 4b in CH2Cl2 solution at room temp...
Figure 5: Emission spectra of the azulene-containing terpyridine, 4a and 4b in CH2Cl2 solution (2.59 × 10−5 M...
Figure 6: Selected Kohn–Sham orbitals and orbital energies for 4a and 4b, obtained with three different funct...
Figure 7: DPV-traces (with baseline correction) of 0.5 mM solutions of 4a (solid) and 4b (dash) in DMF, with ...
Figure 8: Absorption spectra of a 4.26 mM solution of 4a in methanol upon titration with an aqueous HgCl2 sol...
Figure 9: Absorption spectra of a 4.26 mM solution of 4a in methanol upon titration with CdCl2 aqueous soluti...
Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides
- Franziska Hemmerling and
- Frank Hahn
Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148
- thiotetronates 166–168, it was postulated that this mechanism is general for the formation of this type of heterocycle. 1.7.2 Oxidative cyclisation: Aurones. Aurones are yellow coloured pigments of ornamental flowers that belong to the flavonoids. They are structurally closely related to chalcones, from which
- they differ by a central, annelated furan-3-one moiety instead of an acrylate unit (Scheme 25) [149]. Their biosynthesis proceeds from chalcones by an oxidation–conjugate addition cascade catalysed by plant phenol oxidases (PPOs) [150][151]. The PPO aureusidin synthase plays a central role in aurone
- consumption of hydrogen peroxide. It has been shown that the AS is substrate tolerant and accepts different hydroxylation patterns as well as glycosylations on the chalcone A and B rings [154]. However, the oxidative half-reaction only occurs with chalcones and not with other aryl substrates like L-tyrosine
Graphical Abstract
Scheme 1: Schematic description of the cyclisation reaction catalysed by TE domains. In most cases, the nucle...
Scheme 2: Mechanisms for the formation of oxygen heterocycles. The degree of substitution can differ from tha...
Scheme 3: Pyran-ring formation in pederin (24) biosynthesis. Incubation of recombinant PedPS7 with substrate ...
Scheme 4: The domain AmbDH3 from ambruticin biosynthesis catalyses the dehydration of 25 and subsequent cycli...
Scheme 5: SalBIII catalyses dehydration of 29 and subsequent cyclisation to tetrahydropyran 30 [18].
Figure 1: All pyranonaphtoquinones contain either the naphtha[2,3-c]pyran-5,10-dione (32) or the regioisomeri...
Scheme 6: Pyran-ring formation in actinorhodin (34) biosynthesis. DNPA: 4-dihydro-9-hydroxy-1-methyl-10-oxo-3H...
Scheme 7: Pyran formation in granaticin (36) biosynthesis. DNPA: 4-dihydro-9-hydroxy-1-methyl-10-oxo-3H-napht...
Scheme 8: Pyran formation in alnumycin (37) biosynthesis. Adapted from [21].
Scheme 9: Biosynthesis of pseudomonic acid A (61). The pyran ring is initially formed in 57 after dehydrogena...
Scheme 10: Epoxidation–cyclisation leads to the formation of the tetrahydropyran ring in the western part of t...
Scheme 11: a) Nonactin (70) is formed from heterodimers of (−)(+)-dimeric nonactic acid and (+)(−)-dimeric non...
Figure 2: Pamamycins (73) are macrodiolide antibiotics containing three tetrahydrofuran moieties, which are a...
Scheme 12: A PS domain homolog in oocydin A (76) biosynthesis is proposed to catalyse furan formation via an o...
Scheme 13: Mechanism of oxidation–furan cyclisation by AurH, which converts (+)-deoxyaureothin (77) into (+)-a...
Scheme 14: Leupyrrin A2 (80) and the proposed biosynthesis of its furylidene moiety [69,70].
Scheme 15: Asperfuranone (93) biosynthesis, adapted from [75].
Figure 3: The four major aflatoxins produced by Aspergilli are the types B1, B2, G1 and G2 (94–97). In the di...
Scheme 16: Overview on aflatoxin B1 (94) biosynthesis. HOMST = 11-hydroxy-O-methylsterigmatocystin [78,79,82-106].
Scheme 17: A zipper mechanism leads to the formation of oxygen heterocycles in monensin biosynthesis [109-111].
Scheme 18: Formation of the 2,6-dioxabicyclo[3.2.1]octane (DBO) ring system in aurovertin B (118) biosynthesis ...
Figure 4: Structures of the epoxide-containing polyketides epothilone A (119) and oleandomycin (120) [123-125].
Scheme 19: Structures of phoslactomycin B (121) (a) and jerangolid A (122) (b). The heterocycle-forming steps ...
Scheme 20: a) Structures of rhizoxin (130) and cycloheximide (131). Model for the formation of δ-lactones (b) ...
Scheme 21: EncM catalyses a dual oxidation sequence and following processing of the highly reactive intermedia...
Figure 5: Mesomeric structures of tetronates [138,139].
Figure 6: Structures of tetronates for which gene clusters have been sequenced. The tetronate moiety is shown...
Scheme 22: Conserved steps for formation and processing in several 3-acyl-tetronate biosynthetic pathways were...
Scheme 23: In versipelostatin A (153) biosynthesis, VstJ is a candidate enzyme for catalysing the [4 + 2] cycl...
Scheme 24: a) Structures of some thiotetronate antibiotics. b) Biosynthesis of thiolactomycin (165) as propose...
Scheme 25: Aureusidine synthase (AS) catalyses phenolic oxidation and conjugate addition of chalcones leading ...
Scheme 26: a) Oxidative cyclisation is a key step in the biosynthesis of spirobenzofuranes 189, 192 and 193. b...
Scheme 27: A bicyclisation mechanism forms a β-lactone and a pyrrolidinone and removes the precursor from the ...
Scheme 28: Spontaneous cyclisation leads to off-loading of ebelactone A (201) from the PKS machinery [163].
Scheme 29: Mechanisms for the formation of nitrogen heterocycles.
Scheme 30: Biosynthesis of highly substituted α-pyridinones. a) Feeding experiments confirmed the polyketide o...
Scheme 31: Acridone synthase (ACS) catalyses the formation of 1,3-dihydroxy-N-methylacridone (224) by condensa...
Scheme 32: A Dieckmann condensation leads to the formation of a 3-acyl-4-hydroxypyridin-2-one 227 and removes ...
Scheme 33: a) Biosynthesis of the pyridinone tenellin (234). b) A radical mechanism was proposed for the ring-...
Scheme 34: a) Oxazole-containing PKS–NRPS-derived natural products oxazolomycin (244) and conglobatin (245). b...
Scheme 35: Structure of tetramic acids 251 (a) and major tautomers of 3-acyltetramic acids 252a–d (b). Adapted...
Scheme 36: Equisetin biosynthesis. R*: terminal reductive domain. Adapted from [202].
Scheme 37: a) Polyketides for which a similar biosynthetic logic was suggested. b) Pseurotin A (256) biosynthe...
Figure 7: Representative examples of PTMs with varying ring sizes and oxidation patterns [205,206].
Scheme 38: Ikarugamycin biosynthesis. Adapted from [209-211].
Scheme 39: Tetramate formation in pyrroindomycin aglycone (279) biosynthesis [213-215].
Scheme 40: Dieckmann cyclases catalyse tetramate or 2-pyridone formation in the biosynthesis of, for example, ...
Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions
- Rajeev S. Menon,
- Akkattu T. Biju and
- Vijay Nair
Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47
- salt 57 catalysed the intramolecular cross-benzoin reaction of chalcones derived from o-phthalaldehydes. The reaction proceeded rapidly (20 min) at room temperature to afford good yields (75–94%) of naphthalenone-based tertiary alcohols 58 (Scheme 35) [52]. The synthesis of bicyclic tertiary alcohols
- . Intramolecular cross-benzoin reaction of chalcones. Synthesis of bicyclic tertiary alcohols by intramolecular benzoin reaction. A multicatalytic Michael–benzoin cascade process for cyclopentanone synthesis. Enamine-NHC dual-catalytic, Michael–benzoin cascade reaction. Iminium-cross-benzoin cascade reaction of
Graphical Abstract
Scheme 1: Breslow’s proposal on the mechanism of the benzoin condensation.
Scheme 2: Imidazolium carbene-catalysed homo-benzoin condensation.
Scheme 3: Homo-benzoin condensation in aqueous medium.
Scheme 4: Homobenzoin condensation catalysed by bis(benzimidazolium) salt 8.
Scheme 5: List of assorted chiral NHC-catalysts used for asymmetric homobenzoin condensation.
Scheme 6: A rigid bicyclic triazole precatalyst 15 in an efficient enantioselective benzoin reaction.
Scheme 7: Inoue’s report of cross-benzoin reactions.
Scheme 8: Cross-benzoin reactions catalysed by thiazolium salt 17.
Scheme 9: Catalyst-controlled divergence in cross-benzoin reactions.
Scheme 10: Chemoselective cross-benzoin reactions catalysed by a bulky NHC.
Scheme 11: Selective intermolecular cross-benzoin condensation reactions of aromatic and aliphatic aldehydes.
Scheme 12: Chemoselective cross-benzoin reaction of aliphatic and aromatic aldehydes.
Scheme 13: Cross-benzoin reactions of trifluoromethyl ketones developed by Enders.
Scheme 14: Cross-benzoin reactions of aldehydes and α-ketoesters.
Scheme 15: Enantioselective cross-benzoin reactions of aliphatic aldehydes and α-ketoesters.
Scheme 16: Dynamic kinetic resolution of β-halo-α-ketoesters via cross-benzoin reaction.
Scheme 17: Enantioselective benzoin reaction of aldehydes and alkynones.
Scheme 18: Aza-benzoin reaction of aldehydes and acylimines.
Scheme 19: NHC-catalysed diastereoselective synthesis of cis-2-amino 3-hydroxyindanones.
Scheme 20: Cross-aza-benzoin reactions of aldehydes with aromatic imines.
Scheme 21: Enantioselective cross aza-benzoin reaction of aliphatic aldehydes with N-Boc-imines.
Scheme 22: Chemoselective cross aza-benzoin reaction of aldehydes with N-PMP-imino esters.
Scheme 23: NHC-catalysed coupling reaction of acylsilanes with imines.
Scheme 24: Thiazolium salt-mediated enantioselective cross-aza-benzoin reaction.
Scheme 25: Aza-benzoin reaction of enals with activated ketimines.
Scheme 26: Isatin derived ketimines as electrophiles in cross aza-benzoin reaction with enals.
Scheme 27: Aza-benzoin reaction of aldehydes and phosphinoylimines catalysed by the BAC-carbene.
Scheme 28: Nitrosoarenes as the electrophilic component in benzoin-initiated cascade reaction.
Scheme 29: One-pot synthesis of hydroxamic esters via aza-benzoin reaction.
Scheme 30: Cookson and Lane’s report of intramolecular benzoin condensation.
Scheme 31: Intramolecular cross-benzoin condensation between aldehyde and ketone moieties.
Scheme 32: Intramolecular crossed aldehyde-ketone benzoin reactions.
Scheme 33: Enantioselective intramolecular crossed aldehyde-ketone benzoin reaction.
Scheme 34: Chromanone synthesis via enantioselective intramolecular cross-benzoin reaction.
Scheme 35: Intramolecular cross-benzoin reaction of chalcones.
Scheme 36: Synthesis of bicyclic tertiary alcohols by intramolecular benzoin reaction.
Scheme 37: A multicatalytic Michael–benzoin cascade process for cyclopentanone synthesis.
Scheme 38: Enamine-NHC dual-catalytic, Michael–benzoin cascade reaction.
Scheme 39: Iminium-cross-benzoin cascade reaction of enals and β-oxo sulfones.
Scheme 40: Intramolecular benzoin condensation of carbohydrate-derived dialdehydes.
Scheme 41: Enantioselective intramolecular benzoin reactions of N-tethered keto-aldehydes.
Scheme 42: Asymmetric cross-benzoin reactions promoted by camphor-derived catalysts.
Scheme 43: NHC-Brønsted base co-catalysis in a benzoin–Michael–Michael cascade.
Scheme 44: Divergent catalytic dimerization of 2-formylcinnamates.
Scheme 45: One-pot, multicatalytic asymmetric synthesis of tetrahydrocarbazole derivatives.
Scheme 46: NHC-chiral secondary amine co-catalysis for the synthesis of complex spirocyclic scaffolds.
