Search results
Search for "arylamine" in Full Text gives 35 result(s) in Beilstein Journal of Organic Chemistry.
Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines
- Eugeny Ivakhnenko,
- Vasily Malay,
- Pavel Knyazev,
- Nikita Merezhko,
- Nadezhda Makarova,
- Oleg Demidov,
- Gennady Borodkin,
- Andrey Starikov and
- Vladimir Minkin
Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34
- . Results and Discussion We found that a convenient way toward 6,8-di-tert-butyl-2-(arylamino)-3H-phenoxazin-3-ones 4 involves the short-term heating (30 min) of a molten mixture of 1 and an arylamine at 250 °C, followed by purification of the products by column chromatography. No preliminary grinding of
Graphical Abstract
Scheme 1: Synthesis of 6,8-di-tert-butyl-N-aryl-3H-phenoxazin-3-imines 3 [6] and 6,8-di-tert-butyl-2-(arylamino)...
Figure 1: DFT-calculated molecular geometry (B3LYP/6-311++G(d,p) level) and distribution of electronic densit...
Scheme 2: 6,8-Di-tert-butyl-2-(arylamino)-3H-phenoxazin-3-ones 4 prepared by the one-pot reaction between 6,8...
Figure 2: Molecular structure of 6,8-di-tert-butyl-2-(o-nitrophenylamino)-3H-phenoxazin-3-one (4f). a) Select...
Figure 3: UV–vis spectra of 6,8-di-tert-butyl-2-(arylamino)-3H-phenoxazin-3-ones 4a–h (toluene, c = 2⋅10−5 M, ...
Scheme 3: Synthesis of 14H-quinoxaline[2,3-b]phenoxazines 5 and 6.
Scheme 4: Relative stability of the tautomers 7 and 7a,b of quinoxaline[2,3-b]phenoxazine calculated at the D...
Scheme 5: Preparation of quinoxaline[2,3-b]phenoxazine (7) from 2-amino-3H-phenoxazin-3-one (8) [10] and 2-ethoxy...
Figure 4: Molecular structure of ethyl 2,4-di-tert-butyl-14H-quinoxalino[2,3-b]phenoxazine-10-carboxylate (5c...
Scheme 6: Triphenodioxazine and oxazinophenothiazine derivatives 10 via condensation of 3H-phenoxazin-3-one 1...
Figure 5: a) UV–vis (solid lines) and fluorescence emission (λex = 365 nm, dashed) spectra of compounds 5a–c ...
Figure 6: UV–vis (solid lines) and fluorescence emission (dashed, λex = 365 nm) spectra of compounds 6a,b in ...
Figure 7: UV–vis, fluorescence emission (λex = 500 nm), and fluorescence excitation (λobs = 590 nm) spectra o...
Photoredox catalysis harvesting multiple photon or electrochemical energies
- Mattia Lepori,
- Simon Schmid and
- Joshua P. Barham
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Copper-catalyzed N-arylation of amines with aryliodonium ylides in water
- Kasturi U. Nabar,
- Bhalchandra M. Bhanage and
- Sudam G. Dawande
Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76
- pharmaceutical agents containing the arylamine moiety as an integral part of the structural framework includes molecule such as retigabine (I) [5], an anticonvulsant used as an adjunctive agent in the treatment of partial seizures, folic acid (II) [6], a type of vitamin B12 displaying an important role in
- reaction conditions with iodonium ylide 2a, which reacted sluggishly compared to other arylamines to give the product 3m in 55% yield. Next, 1-naphthylamine also smoothly underwent N-arylation to furnish product 3n in 75% yield. Then we studied the arylation of primary arylamine with iodonium ylide, 2-((4
Graphical Abstract
Figure 1: Representative examples of N-arylamines.
Scheme 1: N-Arylation of amines with hypervalent iodine reagents.
Scheme 2: N-Arylation of primary amines with iodonium ylide. Reaction conditions: 0.2 mmol aniline 1, 0.24 mm...
Scheme 3: N-Arylation of secondary amines with iodonium ylide.
The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition
- Xiu-Yu Chen,
- Hui Zheng,
- Ying Han,
- Jing Sun and
- Chao-Guo Yan
Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73
- ][28][29][30]. The 5,6-unsubstituted 1,4-dihydropyridines can be easily prepared from the three-component reaction of an arylamine, cinnamaldehyde, and methyl acetoacetate [31][32][33][34]. The unsubstituted C=C double bond in 5,6-unsubstituted 1,4-dihydropyridines exhibits high reactivity and could
Graphical Abstract
Scheme 1: Various cycloaddition reactions of 5,6-unsymmetric 1,4-dihydropyridines.
Figure 1: Single crystal structure of the compound 4k.
Figure 2: Single crystal structure of compound 5a.
Figure 3: Single crystal structure of compound 6f.
Scheme 2: Plausible reaction mechanism for the various products 4, 5, and 6.
Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach
- Dileep Kumar Singh and
- Rajesh Kumar
Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71
- were selected and used for the synthesis of 20 examples of N-substituted pyrroles in yields of 62–98%. In this study, it was observed that anilines with electron‐withdrawing groups (i.e., NO2, CF3, F, Cl, Br) deactivated arylamine and gave the corresponding pyrroles in moderate yields, while anilines
Graphical Abstract
Figure 1: Various pyrrole containing molecules.
Scheme 1: Various synthestic protocols for the synthesis of pyrroles.
Figure 2: A tree-diagram showing various conventional and green protocols for Clauson-Kaas pyrrole synthesis.
Scheme 2: A general reaction of Clauson–Kaas pyrrole synthesis and proposed mechanism.
Scheme 3: AcOH-catalyzed synthesis of pyrroles 5 and 7.
Scheme 4: Synthesis of N-substituted pyrroles 9.
Scheme 5: P2O5-catalyzed synthesis of N-substituted pyrroles 11.
Scheme 6: p-Chloropyridine hydrochloride-catalyzed synthesis of pyrroles 13.
Scheme 7: TfOH-catalyzed synthesis of N-sulfonylpyrroles 15, N-sulfonylindole 16, N-sulfonylcarbazole 17.
Scheme 8: Scandium triflate-catalyzed synthesis of N-substituted pyrroles 19.
Scheme 9: MgI2 etherate-catalyzed synthesis and proposed mechanism of N-arylpyrrole derivatives 21.
Scheme 10: Nicotinamide catalyzed synthesis of pyrroles 23.
Scheme 11: ZrOCl2∙8H2O catalyzed synthesis and proposed mechanism of pyrrole derivatives 25.
Scheme 12: AcONa catalyzed synthesis of N-substituted pyrroles 27.
Scheme 13: Squaric acid-catalyzed synthesis and proposed mechanism of N-substituted pyrroles 29.
Figure 3: Reusability of catalyst γ-Fe2O3@SiO2-Sb-IL in six cycles.
Scheme 14: Magnetic nanoparticle-supported antimony catalyst used in the synthesis of N-substituted pyrroles 31...
Scheme 15: Iron(III) chloride-catalyzed synthesis of N-substituted pyrroles 33.
Scheme 16: Copper-catalyzed Clauson–Kaas synthesis and mechanism of pyrroles 35.
Scheme 17: β-CD-SO3H-catalyzed synthesis and proposed mechanism of pyrroles 37.
Figure 4: Recyclability of β-cyclodextrin-SO3H.
Scheme 18: Solvent-free and catalyst-free synthesis and plausible mechanism of N-substituted pyrroles 39.
Scheme 19: Nano-sulfated TiO2-catalyzed synthesis of N-substituted pyrroles 41.
Figure 5: Plausible mechanism for the formation of N-substituted pyrroles catalyzed by nano-sulfated TiO2 cat...
Scheme 20: Copper nitrate-catalyzed Clauson–Kaas synthesis and mechanism of N-substituted pyrroles 43.
Scheme 21: Synthesis of N-substituted pyrroles 45 by using Co catalyst Co/NGr-C@SiO2-L.
Scheme 22: Zinc-catalyzed synthesis of N-arylpyrroles 47.
Scheme 23: Silica sulfuric acid-catalyzed synthesis of pyrrole derivatives 49.
Scheme 24: Bismuth nitrate-catalyzed synthesis of pyrroles 51.
Scheme 25: L-(+)-tartaric acid-choline chloride-catalyzed Clauson–Kaas synthesis and plausible mechanism of py...
Scheme 26: Microwave-assisted synthesis of N-substituted pyrroles 55 in AcOH or water.
Scheme 27: Synthesis of pyrrole derivatives 57 using a nano-organocatalyst.
Figure 6: Nano-ferric supported glutathione organocatalyst.
Scheme 28: Microwave-assisted synthesis of N-substituted pyrroles 59 in water.
Scheme 29: Iodine-catalyzed synthesis and proposed mechanism of pyrroles 61.
Scheme 30: H3PW12O40/SiO2-catalyzed synthesis of N-substituted pyrroles 63.
Scheme 31: Fe3O4@-γ-Fe2O3-SO3H-catalyzed synthesis of pyrroles 65.
Scheme 32: Mn(NO3)2·4H2O-catalyzed synthesis and proposed mechanism of pyrroles 67.
Scheme 33: p-TsOH∙H2O-catalyzed (method 1) and MW-assisted (method 2) synthesis of N-sulfonylpyrroles 69.
Scheme 34: ([hmim][HSO4]-catalyzed Clauson–Kaas synthesis of pyrroles 71.
Scheme 35: Synthesis of N-substituted pyrroles 73 using K-10 montmorillonite catalyst.
Scheme 36: CeCl3∙7H2O-catalyzed Clauson–Kaas synthesis of pyrroles 75.
Scheme 37: Synthesis of N-substituted pyrroles 77 using Bi(NO3)3∙5H2O.
Scheme 38: Oxone-catalyzed synthesis and proposed mechanism of N-substituted pyrroles 79.
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- dialkylpyridines with alkenes. It is to be noted that the ligands’ backbones were found to be crucial for the regioselectivity of the addition to benzylic C(sp3)–H bonds, as N-arylamine-bridged bis(phenolato) Zr complexes provided branched products whereas N-alkylamine-bridged bis(phenolato) Zr complexes provided
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles
- Ekaterina A. Lystsova,
- Maksim V. Dmitriev,
- Andrey N. Maslivets and
- Ekaterina E. Khramtsova
Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46
- ), arylamine (0.45 mmol or 0.49 mmol), and anhydrous toluene (3–4 mL) was stirred in an oven-dried closed microreaction V-vial. aReaction time was 3 h for 11d and 8 h for 11a–c. bMes = 2,4,6-Me3C6H2. Side-reaction of APBTT 1a with arylamine 11b. Reaction of APBTT 1a with compounds 16a–d. Formation of compounds
Graphical Abstract
Figure 1: Biologically active PBTAs.
Scheme 1: Approaches to PBTAs via annulation of benzothiazoles.
Scheme 2: Approaches to PBTAs via annulation of o-aminothiophenols.
Scheme 3: Approach to PBTAs via radical substitution reaction in 1-(2-bromophenyl)-5-(butylsulfanyl)pyrrolidi...
Scheme 4: Approach to PBTAs via intramolecular cyclizations of 1-(2-thiophenyl)pyrroles.
Scheme 5: A new approach to PBTAs via nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazin...
Figure 2: Electrophilic centers in FPDs.
Scheme 6: Reaction of APBTT 1a with methanol (2a).
Scheme 7: Derivatization of PBTA 3aa.
Scheme 8: Reaction of APBTTs 1a–h with alcohols 2a–c. Isolated yields are given; reaction scale: a mixture of ...
Scheme 9: Side-reaction of APBTTs 1 with alcohols 2.
Scheme 10: Transformations of compounds 5 in solutions.
Scheme 11: Reaction of APBTT 1a with benzylamine.
Scheme 12: Derivatization of PBTA 7a.
Scheme 13: Reaction of APBTTs 1a–h and benzylamine. Isolated yields are given; reaction scale: a mixture of 1 ...
Scheme 14: Reaction of APBTT 1a with an excess of benzylamine.
Scheme 15: Reaction of APBTT 1a with morpholine.
Scheme 16: Reaction of APBTT 1a with aniline (11a).
Scheme 17: Derivatization of PBTA 12aa.
Scheme 18: Reaction of APBTTs 1a–h and arylamines 11a–d. Isolated yields are given; reaction scale: a mixture ...
Scheme 19: Side-reaction of APBTT 1a with arylamine 11b.
Scheme 20: Reaction of APBTT 1a with compounds 16a–d.
Scheme 21: Formation of compounds 17 as an undesired process during the synthesis of APBTTs 1.
1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis
- Ruan Carlos B. Ribeiro,
- Patricia G. Ferreira,
- Amanda de A. Borges,
- Luana da S. M. Forezi,
- Fernando de Carvalho da Silva and
- Vitor F. Ferreira
Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5
- isomerization involves two routes: one through the hydrolysis of 22 leading to lawsone (4) and the subsequent addition of arylamines in position C2, and the other involves the addition of arylamines at position C2 of 22, leading to 24 with two equivalents of arylamine, which after hydrolysis of the imine at
Graphical Abstract
Figure 1: Naphthoquinones are commonly used in organic synthesis.
Figure 2: Some important natural and synthetic naphthoquinones.
Scheme 1: Synthetic studies of BNQs and reactions with amines.
Scheme 2: Methods described for the synthesis of β-NQS.
Figure 3: Drugs detected using β-NQSNa.
Scheme 3: Reactions between β-NQS and amines.
Scheme 4: Isomerization of 4-arylamino-1,2-naphthoquinones.
Scheme 5: Synthesis of unsymmetrical 2-amino-4-imino compounds.
Scheme 6: Synthesis of bis(isoxazolyl)naphthoquinones from β-NQS.
Scheme 7: The reaction of β-NQS with 30 followed by cycle condensation.
Scheme 8: Synthesis of 4-(2-amino-5-selenothiazoles)-1,2-naphthoquinones.
Scheme 9: Synthesis of amino- and phenoxy-1,2-naphthoquinones.
Scheme 10: Synthesis of 4-semicarbazide-1,2-naphthoquinone.
Scheme 11: Reactions of 4-azido-1,2-naphthoquinone.
Figure 4: Modifications that can be easily carried out from the products of β-NQS 8.
Scheme 12: Derivatives of 1,2-naphthoquinones obtained from β-NQS.
Scheme 13: Oximes as well as 4-amino- and 4-phenoxy-1,2-naphthoquinone as potential anti-inflammatory agents.
Scheme 14: Synthesis of triazoles from β-NQS.
Scheme 15: Synthesis of naphtho[1,2-d]oxazoles from β-NQS.
Scheme 16: A) Arylation and vinylation of β-NQS catalyzed by Ni(II) salts. B) Transformation of the 1,2-dicarb...
Scheme 17: Benzo[a]carbazole and benzo[c]carbazoles fused with 1,2-naphthoquinone.
Scheme 18: Synthesis of 1,2-naphthoquinones having a C=C bond from β-NQS. Method A: NaOH, EtOH/H2O, 40 °C, 2 h...
Scheme 19: C=C bond formation from β-NQS and substituted acetonitriles.
Recent advances in the application of isoindigo derivatives in materials chemistry
- Andrei V. Bogdanov and
- Vladimir F. Mironov
Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111
- glucose in solution (see polymer 62) [108][109]. The limit of sensitivity of the sensor for nitrogen dioxide was 60 ppm and for glucose 0.026 mM. For the example of the fairly simple arylamine series 63, the possibility of using isoindigo polymer for the detection of explosives (trinitrophenol and
Graphical Abstract
Scheme 1: Representatives of isomeric bisoxindoles.
Scheme 2: Isoindigo-based OSCs with the best efficiency.
Scheme 3: Monoisoindigos with preferred 6,6'-substitution.
Scheme 4: Possibility of aromatic–quinoid structural transition.
Scheme 5: Isoindigo structures with incorporated acceptor nitrogen heterocycles.
Scheme 6: Monoisoindigos bearing pyrenyl substituents.
Scheme 7: p-Alkoxyphenylene-embedded thienylisoindigo with different acceptor anchor units.
Scheme 8: Nonfullerene OSC based on perylene diimide-derived isoindigo.
Scheme 9: Isoindigo as an additive in all-polymer OSCs.
Scheme 10: Bisisoindigos with different linker structures.
Scheme 11: Nonthiophene oligomeric monoisoindigos for OSCs.
Scheme 12: The simplest examples of polymers with a monothienylisoindigo monomeric unit.
Scheme 13: Monothienylisoindigos bearing π-extended electron-donor backbones.
Scheme 14: Role of fluorination and the molecular weight on OSC efficiency on the base of the bithiopheneisoin...
Scheme 15: Trithiopheneisoindigo polymers with variation in the substituent structure.
Scheme 16: Polymeric thienyl-linked bisisoindigos for OSCs.
Scheme 17: Isoindigo bearing the thieno[3,2-b]thiophene structural motif as donor component of OSCs.
Scheme 18: Thienylisoindigos with incorporated aromatic unit.
Scheme 19: One-component nonfullerene OSCs on the base of isoindigo.
Scheme 20: Isoindigo-based nonthiophene aza aromatic polymers as acceptor components of OSCs.
Scheme 21: Polymers with isoindigo substituent as side-chain photon trap.
Scheme 22: Isoindigo derivatives for OFET technology with the best mobility.
Scheme 23: Monoisoindigos as low-molecular-weight semiconductors.
Scheme 24: Polymeric bithiopheneisoindigos for OFET creation.
Scheme 25: Fluorination as a tool to improve isoindigo-based OFET devices.
Scheme 26: Diversely DPP–isoindigo-conjugated polymers for OFETs.
Scheme 27: Isoindigoid homopolymers with differing rigidity.
Scheme 28: Isoindigo-based materials with extended π-conjugation.
Scheme 29: Poly(isoindigothiophene) compounds as sensors for ammonia.
Scheme 30: Sensor devices based on poly(isoindigoaryl) compounds.
Scheme 31: Isoindigo polymers for miscellaneous applications.
Scheme 32: Mono-, rod-like, and polymeric isoindigos as agents for photoacoustic and photothermal cancer thera...
A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates
- Olusesan K. Koleoso,
- Matthew Turner,
- Felix Plasser and
- Marc C. Kimber
Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165
- Scheme 4. Given our interest in the N,N’-aminal functionality [50], we also explored variation of the arylamine nucleophile. 2,4-Dimethylaniline, o-anisole, 2-trifluoromethoxyaniline and 3,5-ditrifluoromethylaniline were all effective in this transformation, giving their labile N,N’-allylaminal products
- subsequent oxidation. We have established that the conjugated N-acyliminium intermediate can be formed from a broad range of allenamide precursors; additionally, the conjugated N-acyliminium intermediate can undergo nucleophilic addition with an arylamine or alcohol nucleophiles at the α- or γ-position, with
- the conjugated N-acyliminium intermediate 14. Photoredox Ir-catalyzed intermolecular addition of bromide 18 and aniline 16 to allenamide 15. Reaction scope (a) allenamide; (b) arylamine nucleophile; (c) alcohol nucleophile. (a) Tentative mechanism for the photoredox-catalyzed formation of the
Graphical Abstract
Scheme 1: Electrophilic activation of allenamides.
Scheme 2: The planned intramolecular radical addition to allenamides generating the conjugated N-acyliminium ...
Scheme 3: Photoredox Ir-catalyzed intermolecular addition of bromide 18 and aniline 16 to allenamide 15.
Scheme 4: Reaction scope (a) allenamide; (b) arylamine nucleophile; (c) alcohol nucleophile.
Scheme 5: (a) Tentative mechanism for the photoredox-catalyzed formation of the conjugated N-acyliminium inte...
Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination
- Yuqing Wang,
- Gaigai Wang,
- Anatoly A. Peshkov,
- Ruwei Yao,
- Muhammad Hasan,
- Manzoor Zaman,
- Chao Liu,
- Stepan Kashtanov,
- Olga P. Pereshivko and
- Vsevolod A. Peshkov
Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163
- performance of other arylamine-derived Ugi adducts 8d–g. The last investigated Ugi adduct 8i featured the variation of the isocyanide component. Conducting fluorinations with this n-butyl isocyanide-derived Ugi adduct 8i, the desired product 12i could be successfully obtained. However, the degree of
- appeared to be consistent with those established for the rest of arylamine-derived Ugi adducts 8d–g. Finally, we attempted to determine the absolute configuration of a stereocenter for the major enantiomer of the representative fluorinated product. Using a sample of product 12e with the ee value of 74% we
Graphical Abstract
Scheme 1: Post-transformations of 2-oxo-aldehyde-derived Ugi adducts 8.
Scheme 2: Synthesis of 2-oxo-aldehyde-derived Ugi adducts.
Figure 1: Molecular representation of the X-ray crystal structure of (S)-12e (slow enantiomer).
Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups
- Xiaowei Li,
- Xiaolin Shi,
- Xiangqian Li and
- Dayong Shi
Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218
Graphical Abstract
Scheme 1: The main three strategies of fluorination: nucleophilic, electrophilic and radical fluorination.
Scheme 2: Doyle’s Pd-catalyzed fluorination of allylic chlorides.
Scheme 3: Allylic fluorination of 2- and 3-substituted propenyl esters.
Scheme 4: Regioselective allylic fluorination of cinnamyl phosphorothioate esters.
Scheme 5: Palladium-catalyzed aliphatic C–H fluorination reported by Doyle.
Scheme 6: Pd-catalyzed enantioselective fluorination of α-ketoesters followed by stereoselective reduction to...
Scheme 7: Pd-catalyzed C(sp3)–H fluorination of oxindoles.
Scheme 8: C–H fluorination of 8-methylquinoline derivatives with F− reagents.
Scheme 9: Fluorination of α-cyano acetates reported by van Leeuwen.
Scheme 10: The catalytic enantioselective electrophilic C–H fluorination of α-chloro-β-keto phosphonates.
Scheme 11: Fluorination of unactivated C(sp3)–H bonds directed by the bidentate PIP auxiliary.
Scheme 12: Fluorination of C(sp3)–H bonds at the β-position of carboxylic acids.
Scheme 13: Enantioselective benzylic C–H fluorination with a chiral transient directing group.
Scheme 14: Microwave-heated Pd-catalyzed fluorination of aryl alcohols.
Scheme 15: Fluorination of aryl potassium trifluoroborates.
Scheme 16: C(sp2)–F bond formation using precatalyst [L·Pd]2(cod).
Scheme 17: Pd-catalyzed fluorination of (hetero)aryl triflates and bromides.
Scheme 18: The Pd-catalyzed C–H fluorination of arenes with Selectfluor/NFSI.
Scheme 19: Pd(II)-catalyzed ortho-monofluorination protocol for benzoic acids.
Scheme 20: Pd-catalyzed C(sp2)–H bond fluorination of 2-arylbenzothiazoles.
Scheme 21: Nitrate-promoted fluorination of aromatic and olefinic C(sp2)–H bonds and proposed mechanism.
Scheme 22: Fluorination of oxalyl amide-protected benzylamine derivatives.
Scheme 23: C–H fluorination of benzaldehydes with orthanilic acids as transient directing group.
Scheme 24: Pd(II)-catalyzed aryl C–H fluorination with various directing groups.
Scheme 25: Cu-catalyzed aliphatic, allylic, and benzylic fluorination.
Scheme 26: Cu-catalyzed SN2 fluorination of primary and secondary alkyl bromides.
Scheme 27: Copper-catalyzed fluorination of alkyl triflates.
Scheme 28: Cu-catalyzed fluorination of allylic bromides and chlorides.
Scheme 29: Synthetic strategy for the fluorination of active methylene compounds.
Scheme 30: Fluorination of β-ketoesters using a tartrate-derived bidentate bisoxazoline-Cu(II) complex.
Scheme 31: Highly enantioselective fluorination of β-ketoesters and N-Boc-oxindoles.
Scheme 32: Amide group-assisted site-selective fluorination of α-bromocarbonyl compounds.
Scheme 33: Cu-mediated aryl fluorination reported by Sanford [77].
Scheme 34: Mono- or difluorination reactions of benzoic acid derivatives.
Scheme 35: Cu-catalyzed fluorination of diaryliodonium salts with KF.
Scheme 36: Copper(I)-catalyzed cross-coupling of 2-pyridylaryl bromides.
Scheme 37: AgNO3-catalyzed decarboxylative fluorination of aliphatic carboxylic acids.
Scheme 38: The Mn-catalyzed aliphatic and benzylic C–H fluorination.
Scheme 39: Iron(II)-promoted C–H fluorination of benzylic substrates.
Scheme 40: Ag-catalyzed fluorodecarboxylation of carboxylic acids.
Scheme 41: Vanadium-catalyzed C(sp3)–H fluorination.
Scheme 42: AgNO3-catalyzed radical deboronofluorination of alkylboronates and boronic acids.
Scheme 43: Selective heterobenzylic C–H fluorination with Selectfluor reported by Van Humbeck.
Scheme 44: Fe(II)-catalyzed site-selective fluorination guided by an alkoxyl radical.
Scheme 45: Fluorination of allylic trichloroacetimidates reported by Nguyen et al.
Scheme 46: Iridium-catalyzed fluorination of allylic carbonates with TBAF(t-BuOH)4.
Scheme 47: Iridium-catalyzed asymmetric fluorination of allylic trichloroacetimidates.
Scheme 48: Cobalt-catalyzed α-fluorination of β-ketoesters.
Scheme 49: Nickel-catalyzed α-fluorination of various α-chloro-β-ketoesters.
Scheme 50: Ni(II)-catalyzed enantioselective fluorination of oxindoles and β-ketoesters.
Scheme 51: Scandium(III)-catalyzed asymmetric C–H fluorination of unprotected 3-substituted oxindoles.
Scheme 52: Iron-catalyzed directed C–H fluorination.
Scheme 53: Electrophilic silver-catalyzed Ar–F bond-forming reaction from arylstannanes.
Figure 1: Nucleophilic, electrophilic and radical CF3 sources.
Scheme 54: Cu(I)-catalyzed allylic trifluoromethylation of unactivated terminal olefins.
Scheme 55: Direct copper-catalyzed trifluoromethylation of allylsilanes.
Scheme 56: Cupper-catalyzed enantioselective trifluoromethylation of five and six-membered ring β-ketoesters.
Scheme 57: Cu-catalyzed highly stereoselective trifluoromethylation of secondary propargyl sulfonates.
Scheme 58: Remote C(sp3)–H trifluoromethylation of carboxamides and sulfonamides.
Scheme 59: Trifluoromethylation of allylsilanes with photoredox catalysis.
Scheme 60: Ag-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids in aqueous CH3CN.
Scheme 61: Decarboxylative trifluoromethylation of aliphatic carboxylic acids via combined photoredox and copp...
Scheme 62: Palladium-catalyzed Ar–CF3 bond-forming reaction.
Scheme 63: Palladium-catalyzed trifluoromethylation of arenes with diverse heterocyclic directing groups.
Scheme 64: Pd-catalyzed trifluoromethylation of indoles as reported by Liu.
Scheme 65: Pd-catalyzed trifluoromethylation of vinyl triflates and vinyl nonaflates.
Scheme 66: Pd(II)-catalyzed ortho-trifluoromethylation of aromatic C–H bonds.
Scheme 67: Visible-light-induced Pd(OAc)2-catalyzed ortho-trifluoromethylation of acetanilides with CF3SO2Na.
Scheme 68: CuI-catalyzed trifluoromethylation of aryl- and alkenylboronic acids.
Scheme 69: Cu-catalyzed trifluoromethylation of aryl- and vinylboronic acids.
Scheme 70: Copper-catalyzed trifluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 71: Formation of C(sp2)–CF3 bond catalyzed by copper(I) complex.
Scheme 72: Loh’s Cu(I)-catalyzed trifluoromethylation of enamides and electron-deficient alkenes.
Scheme 73: Copper and iron-catalyzed decarboxylative tri- and difluoromethylation.
Scheme 74: Cu-catalyzed trifluoromethylation of hydrazones developed by Bouyssi.
Scheme 75: Cu(I)-catalyzed trifluoromethylation of terminal alkenes.
Scheme 76: Cu/Ag-catalyzed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 77: Copper-catalyzed direct alkenyl C–H trifluoromethylation.
Scheme 78: Copper(I/II)-catalyzed direct trifluoromethylation of styrene derivatives.
Scheme 79: Regioselective trifluoromethylation of pivalamido arenes and heteroarenes.
Scheme 80: Synthesis of trifluoromethylquinones in the presence of copper(I).
Scheme 81: Oxidative trifluoromethylation of imidazoheterocycles in ionic liquid/water.
Scheme 82: A mild and fast continuous-flow trifluoromethylation of coumarins using a CuI/CF3SO2Na/TBHP system.
Scheme 83: Copper-catalyzed oxidative trifluoromethylation of various 8-aminoquinolines.
Scheme 84: PA-directed copper-catalyzed trifluoromethylation of anilines.
Scheme 85: Trifluoromethylation of potassium vinyltrifluoroborates catalyzed by Fe(II).
Scheme 86: Alkenyl trifluoromethylation catalyzed by Ru(phen)3Cl2 as photocatalyst.
Scheme 87: Ru-catalyzed trifluoromethylation of alkenes by Akita’s group.
Scheme 88: Ir-catalyzed Cvinyl–CF3 bond formation of α,β-unsaturated carboxylic acids.
Scheme 89: Ag(I)-catalyzed denitrative trifluoromethylation of β-nitrostyrenes.
Scheme 90: Photocatalyzed direct trifluoromethylation of aryl and heteroaryl C–H bonds.
Scheme 91: Rhenium (MTO)-catalyzed direct trifluoromethylation of aromatic substrates.
Scheme 92: Trifluoromethylation of unprotected anilines under [Ir(ppy)3] catalyst.
Scheme 93: Oxidative trifluoromethylation of imidazopyridines and imidazoheterocycles.
Scheme 94: Ruthenium-catalyzed trifluoromethylation of (hetero)arenes with trifluoroacetic anhydride.
Scheme 95: Phosphovanadomolybdic acid-catalyzed direct C–H trifluoromethylation.
Scheme 96: Picolinamide-assisted ortho-trifluoromethylation of arylamines.
Scheme 97: A nickel-catalyzed C–H trifluoromethylation of free anilines.
Scheme 98: Cu-mediated trifluoromethylation of terminal alkynes reported by Qing.
Scheme 99: Huang’s C(sp)–H trifluoromethylation using Togni’s reagent.
Scheme 100: Cu-catalyzed methods for trifluoromethylation with Umemoto’s reagent.
Scheme 101: The synthesis of alkynyl-CF3 compounds in the presence of fac-[Ir(ppy)3] under visible-light irradi...
Scheme 102: Pd-catalyzed Heck reaction reported by Reutrakul.
Scheme 103: Difluoromethylation of enamides and ene-carbamates.
Scheme 104: Difluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 105: Copper-catalyzed direct C(sp2)–H difluoroacetylation reported by Pannecoucke and co-workers.
Scheme 106: Difluoroalkylation of aldehyde-derived hydrazones with functionalized difluoromethyl bromides.
Scheme 107: Photoredox-catalyzed C–H difluoroalkylation of aldehyde-derived hydrazones.
Scheme 108: Synergistic ruthenium(II)-catalyzed C–H difluoromethylation reported by Ackermann.
Scheme 109: Visible-light photocatalytic decarboxylation of α,β-unsaturated carboxylic acids.
Scheme 110: Synthesis of difluorinated ketones via S-alkyl dithiocarbamates obtained from acyl chlorides and po...
Scheme 111: Synthesis of aryl and heteroaryl difluoromethylated phosphonates.
Scheme 112: Difluoroalkylation of secondary propargyl sulfonates using Cu as the catalyst.
Scheme 113: Ru(II)-mediated para-selective difluoromethylation of anilides and their derivatives.
Scheme 114: Bulky diamine ligand promoted cross-coupling of difluoroalkyl bromides.
Scheme 115: Copper-catalyzed C3–H difluoroacetylation of quinoxalinones.
Scheme 116: Copper(I) chloride-catalyzed trifluoromethylthiolation of enamines, indoles and β-ketoesters.
Scheme 117: Copper-boxmi-catalyzed asymmetric trifluoromethylthiolation of β-ketoesters.
Scheme 118: Direct Cu-catalyzed trifluoromethylthiolation of boronic acids and alkynes.
Scheme 119: Cu-catalyzed synthesis of α-trifluoromethylthio-substituted ketones.
Scheme 120: Trifluoromethylthiolation reactions promoted by diazotriflone and copper.
Scheme 121: Halide activation of N-(trifluoromethylthio)phthalimide.
Scheme 122: The visible light-promoted trifluoromethylthiolation reported by Glorius.
Scheme 123: Synthesis of α-trifluoromethylthioesters via Goossen’s approach.
Scheme 124: Photoinduced trifluoromethylthiolation of diazonium salts.
Scheme 125: Ag-mediated trifluoromethoxylation of aryl stannanes and arylboronic acids.
Scheme 126: Catalytic (hetero)aryl C–H trifluoromethoxylation under visible light.
Scheme 127: Photoinduced C–H-bond trifluromethoxylation of (hetero)arenes.
Steroid diversification by multicomponent reactions
- Leslie Reguera,
- Cecilia I. Attorresi,
- Javier A. Ramírez and
- Daniel G. Rivera
Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121
- presence of I2 as catalyst. The mechanism follows the initial formation of the imine compound between the aldehyde and the arylamine, followed by an imino-Diels–Alder reaction with the enolate generated from the ketosteroid. The reaction is highly regioselective for the enolization of the ketone, thus
Graphical Abstract
Figure 1: Structures of natural steroids of A) animal and B) plant origin.
Scheme 1: Synthesis of a steroidal β-lactam by Ugi reaction of a cholanic aldehyde [14].
Scheme 2: Synthetic route to steroidal 2,5-diketopiperazines based on a diastereoselective Ugi-4CR with an an...
Scheme 3: Multicomponent synthesis of a heterocycle–steroid hybrid using a ketosteroid as carbonyl component [18]....
Scheme 4: Synthesis of peptidomimetic–steroid hybrids using the Ugi-4CR with spirostanic amines and carboxyli...
Scheme 5: Synthesis of azasteroids using the Ugi-4CR with androstanic and pregnanic carboxylic acids [22].
Figure 2: Ugi-4CR-derived library of androstanic azasteroids with diverse substitution patterns at the phenyl...
Scheme 6: Synthesis of 4-azacholestanes by an intramolecular Ugi-4C-3R [26].
Scheme 7: Synthesis of amino acid–steroid hybrid by multiple Ugi-4CR using steroidal isocyanides [29].
Scheme 8: Synthesis of ecdysteroid derivatives by Ugi-4CR using a steroidal isocyanide [30].
Scheme 9: Stereoselective multicomponent synthesis of a steroid–tetrahydropyridine hybrid using a chiral bifu...
Scheme 10: Pd(II)-catalyzed three-component reaction with an alkynyl seco-cholestane [34].
Scheme 11: Multicomponent synthesis of steroid–thiazole hybrids from a steroidal ketone [36].
Scheme 12: Synthesis of cholanic pseudo-peptide derivatives by novel MCRs based on the reactivity of ynamide [37,38].
Scheme 13: Synthesis of steroid-fused pyrimidines and pyrimidones using the Biginelli-3CR [39,42,43].
Scheme 14: Synthesis of steroidal pyridopyrimidines by a reaction sequence comprising a 4CR followed by a post...
Scheme 15: Synthesis of steroid-fused pyrimidines by MCR of 2-hydroxymethylene-3-ketosteroids [46].
Scheme 16: Synthesis of steroid-fused naphthoquinolines by the Kozlov–Wang MCR using ketosteroids [50,51].
Scheme 17: Conjugation of steroids to carbohydrates and peptides by the Ugi-4CR [62,63].
Scheme 18: Solid-phase multicomponent conjugation of peptides to steroids by the Ugi-4CR [64].
Scheme 19: Solid-phase multicomponent conjugation of peptides to steroids by the Petasis-3CR [68].
Scheme 20: Synthesis of steroidal macrobicycles (cages) by multiple multicomponent macrocyclizations based on ...
Scheme 21: One-pot synthesis of steroidal cages by double Ugi-4CR-based macrocyclizations [76].
Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection
- Shahien Shahsavari,
- Dhananjani N. A. M. Eriyagama,
- Bhaskar Halami,
- Vagarshak Begoyan,
- Marina Tanasova,
- Jinsen Chen and
- Shiyue Fang
Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108
- using large excess is not ideal for a technology aimed to be practically and universally useful. In this paper, we report the use of dimethyl-Dmoc (dM-Dmoc), which we previously studied for alkyl- and arylamine protections [44], in place of Dmoc for nucleobase protection for ODN synthesis (Scheme 1
Graphical Abstract
Scheme 1: Comparison of Dmoc and dM-Dmoc as nucleobase protecting groups for ODN synthesis.
Figure 1: dM-Dmoc phosphoramidite monomers and CPG with Dmoc linker.
Scheme 2: Synthesis of compound 5 [44], nucleoside phosphoramidite monomers 3a–c and phosphoramidite capping agen...
Figure 2: Structure of phosphoramidites containing electrophilic groups.
Scheme 3: Synthesis of ester-containing phosphoramidite 26a.
Figure 3: ODN sequences 30a–e. Their 5'-tritylated versions are labeled as 30a-tr, 30b-tr, 30c-tr, 30d-tr, an...
Figure 4: RP HPLC profiles of (a) crude 30a-tr, (b) pure 30a-tr, (c) crude 30a, (d) pure 30a, (e) crude 30c-tr...
Figure 5: PAGE analyses of ODNs 30a–e. Lanes 1–5 are ODNs 30a–e, respectively.
Figure 6: MALDI–TOF MS of (a) ODN 30a and (b) 30c.
Scheme 4: ODN deprotection and cleavage under non-nucleophilic conditions.
An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes
- Hashem Sharghi,
- Pezhman Shiri and
- Mahdi Aberi
Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253
- protected aniline derivatives were obtained by the solvent-free reaction of anilines with 1,3-diketones at 120 °C or 140 °C in the presence of 2 equiv of water under 1 atm O2 atmosphere (Scheme 16). The probable reaction pathway for this reaction is shown in Scheme 16. Arylamine 15 attacks the activated
Graphical Abstract
Figure 1: Different types of sulfonated materials as acid catalysts.
Scheme 1: Synthetic route of 3-methyl-1-sulfo-1H-imidazolium metal chloride ILs and their catalytic applicati...
Scheme 2: Synthetic route of 1,3-disulfo-1H-imidazolium transition metal chloride ILs and their catalytic app...
Scheme 3: Synthetic route of 1,3-disulfoimidazolium carboxylate ILs and their catalytic applications in the s...
Scheme 4: Synthetic route of [BiPy](HSO3)2Cl2 and [Dsim]HSO4 ILs and their catalytic applications for the syn...
Scheme 5: The catalytic applications of (C4(DABCO-SO3H)2·4Cl) IL for the synthesis of spiro-isatin derivative...
Scheme 6: The catalytic applications of (C4(DABCO-SO3H)2·4Cl) IL for the synthesis of bis 2-amino-4H-pyran de...
Scheme 7: The synthetic route of N,N-disulfo-1,1,3,3-tetramethylguanidinium carboxylate ILs and their catalyt...
Scheme 8: The catalytic application of 1-methyl-3-sulfo-1H-imidazolium tetrachloroferrate IL in the synthesis...
Scheme 9: The synthetic route of 3-sulfo-1H-imidazolopyrimidinium hydrogen sulfate IL and its catalytic appli...
Scheme 10: The results for the synthesis of bis(indolyl)methanes and di(bis(indolyl)methyl)benzenes in the pre...
Scheme 11: The catalytic applications of 1-(1-sulfoalkyl)-3-methylimidazolium chloride acidic ILs for the hydr...
Scheme 12: The synthetic route of immobilized 1,4-diazabicyclo[2.2.2]octanesulfonic acid chloride on SiO2 and ...
Scheme 13: The catalytic application of a silica-bonded sulfoimidazolium chloride for the synthesis of 12-aryl...
Scheme 14: The synthetic route of the SBA-15-Ph-SO3H and its catalytic applications for the synthesis of 2H-in...
Scheme 15: The synthetic route for heteropolyanion-based ionic liquids immobilized on mesoporous silica SBA-15...
Scheme 16: Some mechanism aspects of SSA catalyst for the protection of amine derivatives.
Scheme 17: The synthetic route for MWCNT-SO3H and its catalytic application for the synthesis of N-substituted...
Scheme 18: The sulfonic acid-functionalized polymers (P-SO3H) covalently grafted on multi-walled carbon nanotu...
Scheme 19: The transesterification reaction in the presence of S-MWCNTs.
Scheme 20: The synthetic route for the new hypercrosslinked supermicroporous polymer via the Friedel–Crafts al...
Scheme 21: The synthetic route for a new microporous copolymer via the Friedel–Crafts alkylation reaction of t...
Scheme 22: The synthetic route for sulfonated polynaphthalene and its catalytic application for the amidoalkyl...
Scheme 23: The synthetic route of the acidic carbon material and its catalytic application in the etherificatio...
Scheme 24: The synthetic route of the acidic carbon materials and their catalytic applications for the esterif...
Scheme 25: The sulfonated MWCNTs.
Scheme 26: The sulfonated nanoscaled diamond powder for the dehydration of D-xylose into furfural.
Scheme 27: The synthetic route and catalytic application of the GR-SO3H.
The mechanochemical synthesis of quinazolin-4(3H)-ones by controlling the reactivity of IBX
- Md Toufique Alam,
- Saikat Maiti and
- Prasenjit Mal
Beilstein J. Org. Chem. 2018, 14, 2396–2403, doi:10.3762/bjoc.14.216
- , after extraction of the reaction mixture with DCM, followed by silica gel column chromatography with ethyl acetate/hexane 1:5 as eluent provided product 3a (684 mg, 68%). a) Explosion was observed when an arylamine was mixed with aldehydes in the presence of IBX. b) Benzamide was found to be unreactive
Graphical Abstract
Figure 1: a) Explosion was observed when an arylamine was mixed with aldehydes in the presence of IBX. b) Ben...
Figure 2: Comparison of the current work with the existing literature reports.
Figure 3: Synthesis of quinazolin-4(3H)-one derivatives from the reaction of 1 with liquid aldehydes. aYields...
Figure 4: Synthesis of quinazolin-4(3H)-one derivatives from reaction of 1 and solid aldehydes. aYields with ...
Figure 5: Crystal structure of 3a (CCDC No. 1823611).
Figure 6: Plausible mechanism for the quinazolin-4(3H)-ones synthesis using IBX.
Scheme 1: Large scale synthesis of 3a.
An amine protecting group deprotectable under nearly neutral oxidative conditions
- Shahien Shahsavari,
- Chase McNamara,
- Mark Sylvester,
- Emily Bromley,
- Savannah Joslin,
- Bao-Yuan Lu and
- Shiyue Fang
Beilstein J. Org. Chem. 2018, 14, 1750–1757, doi:10.3762/bjoc.14.149
- . Therefore, for protecting arylamines, we used conditions for the formation of hindered O-tert-alkyl N-arylcarbamates we reported earlier [20]. Treating one equivalent 3e with two equivalents LDA and one equivalent 4 in THF gave the desired arylamine dM-Dmoc carbamate 5e in synthetically useful yield (Table
- 3c are also aliphatic amines, but their yields were lower. This might be caused by evaporation due to their low boiling points during work-up and purification. The arylamines were obtained in lower yields (Table 1, entries 5–8) compared with the aliphatic ones. Among the four arylamine examples, 5g
Graphical Abstract
Scheme 1: Dmoc and dM-Dmoc protection and deprotection of amines.
Scheme 2: Selective deprotection of dM-Dmoc-, Boc- and Fmoc-protected amines.
Recent advances in phosphorescent platinum complexes for organic light-emitting diodes
- Cristina Cebrián and
- Matteo Mauro
Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124
- ] platinum complexes featuring tertiary arylamine motifs and their chemical structure is displayed in Figure 20. Such complexes, whose structure is derived from the parental symmetric systems previously reported by Huo and co-workers [91], bear a 3-methylindole, a carboxylic and a dangling phenoxy moiety
Graphical Abstract
Figure 1: Molecular structure of neutral platinum(II) complex 1 bearing four monodentate ligands; cy = cycloh...
Figure 2: Chemical structure of the dinuclear Pt complexes 2a–b and 3 [20].
Figure 3: Molecular structure of platinum(II) complexes bearing isoquinolinylpyrazolates; dip = 2,6-diisoprop...
Figure 4: Selected neutral platinum(II) complexes featuring dianionic biazolate and neutral bipyridines [27].
Figure 5: Selected neutral platinum(II) complexes from bipyrazolate and carbene-based chelates [34,35].
Figure 6: Cyclometalated thiazol-2-ylidene platinum(II) complexes with different acetylacetonate ligands [37].
Figure 7: Neutral platinum(II) complexes 13–15 bearing azolate ligands [13].
Figure 8: Chemical structure of neutral platinum(II) complexes 16–18 bearing azine-pyrazolato bidentate ligan...
Figure 9: Molecular structure of carbene-containing cyclometallated alkynylplatinum(II) complexes 19–21 [41].
Figure 10: Chemical structure of platinum(II) complexes 22a–d bearing asymmetric C^N^N tridentate ligands [53].
Figure 11: Chemical structure of platinum(II) complexes 23 bearing bis-cyclometalating 2,6-dipyridylbenzene ty...
Figure 12: Molecular structure of dendritic carbazole-containing alkynyl-platinum(II) complexes 24a–d [62].
Figure 13: Molecular structure of bipolar alkynyl-platinum(II) complexes 25 bearing carbazole and electron-acc...
Figure 14: Molecular structures of neutral platinum(II) complexes comprising donor-acceptor alkynyls (26) or e...
Figure 15: Chemical structure of the asymmetric Pt(II) derivatives 28 bearing triazole and tetrazole moieties ...
Figure 16: Molecular structure of the tetradentate platinum complexes 29–32 bearing N^C^C^N and C^C^C^N ligand...
Figure 17: Chemical structure of the tetradentate Pt complexes 33–38 based on N^C^C^N-type of ligands [80-84].
Figure 18: Chemical structure of the macrocyclic tetradentate platinum complexes reported by Wang and co-worke...
Figure 19: Molecular structure of complex 41–46 [88,89].
Figure 20: Molecular structure of asymmetric derivatives 47–49 based on triaryl-type of bridge [90].
Figure 21: Chemical structure of the asymmetric tetradentate derivatives 50 and 51 based on spirofluorene link...
Figure 22: Molecular structure of the pyridylazolate-based complexes 52–54 reported by Chi and co-workers [97].
Figure 23: Chemical structure of the red-to-NIR emitting complexes 55–57 bearing donor–acceptor triphenylamino...
Figure 24: Molecular structures of the Pt(IV) derivatives 58 and 59 employed as triplet emitters in solution-p...
Progress in copper-catalyzed trifluoromethylation
- Guan-bao Li,
- Chao Zhang,
- Chun Song and
- Yu-dao Ma
Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11
- aryldiazonium ion, which is generated in situ from the corresponding arylamine. At the same time, a copper-catalyzed Sandmeyer trifluoromethylation of arenediazonium tetrafluoroborates was also reported by the group of Gooßen (Scheme 25) [44]. This reaction was conducted under mild conditions using TMSCF3 as
Graphical Abstract
Figure 1: Selected examples of pharmaceutical and agrochemical compounds containing the trifluoromethyl group....
Scheme 1: Introduction of a diamine into copper-catalyzed trifluoromethylation of aryl iodides.
Scheme 2: Addition of a Lewis acid into copper-catalyzed trifluoromethylation of aryl iodides and the propose...
Scheme 3: Trifluoromethylation of heteroaromatic compounds using S-(trifluoromethyl)diphenylsulfonium salts a...
Scheme 4: The preparation of a new trifluoromethylation reagent and its application in trifluoromethylation o...
Scheme 5: Trifluoromethylation of aryl iodides using CF3CO2Na as a trifluoromethyl source.
Scheme 6: Trifluoromethylation of aryl iodides using MTFA as a trifluoromethyl source.
Scheme 7: Trifluoromethylation of aryl iodides using CF3CO2K as a trifluoromethyl source.
Scheme 8: Trifluoromethylation of aryl iodides and heteroaryl bromides using [Cu(phen)(O2CCF3)] as a trifluor...
Scheme 9: Trifluoromethylation of aryl iodides with DFPB and the proposed mechanism.
Scheme 10: Trifluoromethylation of aryl iodides using TCDA as a trifluoromethyl source. Reaction conditions: [...
Scheme 11: The mechanism of trifluoromethylation using Cu(II)(O2CCF2SO2F)2 as a trifluoromethyl source.
Scheme 12: Trifluoromethylation of benzyl bromide reported by Shibata’s group.
Scheme 13: Trifluoromethylation of allylic halides and propargylic halides reported by the group of Nishibayas...
Scheme 14: Trifluoromethylation of propargylic halides reported by the group of Nishibayashi.
Scheme 15: Trifluoromethylation of alkyl halides reported by Nishibayashi’s group.
Scheme 16: Trifluoromethylation of pinacol esters reported by the group of Gooßen.
Scheme 17: Trifluoromethylation of primary and secondary alkylboronic acids reported by the group of Fu.
Scheme 18: Trifluoromethylation of boronic acid derivatives reported by the group of Liu.
Scheme 19: Trifluoromethylation of organotrifluoroborates reported by the group of Huang.
Scheme 20: Trifluoromethylation of aryl- and vinylboronic acids reported by the group of Shibata.
Scheme 21: Trifluoromethylation of arylboronic acids via the merger of photoredox and Cu catalysis.
Scheme 22: Trifluoromethylation of arylboronic acids reported by Sanford’s group. Isolated yield. aYields dete...
Scheme 23: Trifluoromethylation of arylboronic acids and vinylboronic acids reported by the group of Beller. Y...
Scheme 24: Copper-mediated Sandmeyer type trifluoromethylation using Umemoto’s reagent as a trifluoromethylati...
Scheme 25: Copper-mediated Sandmeyer type trifluoromethylation using TMSCF3 as a trifluoromethylation reagent ...
Scheme 26: One-pot Sandmeyer trifluoromethylation reported by the group of Gooßen.
Scheme 27: Copper-catalyzed trifluoromethylation of arenediazonium salts in aqueous media.
Scheme 28: Copper-mediated Sandmeyer trifluoromethylation using Langlois’ reagent as a trifluoromethyl source ...
Scheme 29: Trifluoromethylation of terminal alkenes reported by the group of Liu.
Scheme 30: Trifluoromethylation of terminal alkenes reported by the group of Wang.
Scheme 31: Trifluoromethylation of tetrahydroisoquinoline derivatives reported by Li and the proposed mechanis...
Scheme 32: Trifluoromethylation of phenol derivatives reported by the group of Hamashima.
Scheme 33: Trifluoromethylation of hydrazones reported by the group of Baudoin and the proposed mechanism.
Scheme 34: Trifluoromethylation of benzamides reported by the group of Tan.
Scheme 35: Trifluoromethylation of heteroarenes and electron-deficient arenes reported by the group of Qing an...
Scheme 36: Trifluoromethylation of N-aryl acrylamides using CF3SO2Na as a trifluoromethyl source.
Scheme 37: Trifluoromethylation of aryl(heteroaryl)enol acetates using CF3SO2Na as the source of CF3 and the p...
Scheme 38: Trifluoromethylation of imidazoheterocycles using CF3SO2Na as a trifluoromethyl source and the prop...
Scheme 39: Copper-mediated trifluoromethylation of terminal alkynes using TMSCF3 as a trifluoromethyl source a...
Scheme 40: Improved copper-mediated trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 41: Copper-catalyzed trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 42: Copper-catalyzed trifluoromethylation of terminal alkynes using Togni’s reagent and the proposed me...
Scheme 43: Copper-catalyzed trifluoromethylation of terminal alkynes using Umemoto’s reagent reported by the g...
Scheme 44: Copper-catalyzed trifluoromethylation of 3-arylprop-1-ynes reported by Xiao and Lin and the propose...
Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity
- Louis P. Sandjo,
- Victor Kuete and
- Maique W. Biavatti
Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183
- -acetyldopamine (B) into an O-quinone derivative which reacted itself with the arylamine (A) through a Michael addition mechanism and the acridine core was formed via a nucleophilic condensation process. The addition step was also facilitated by CeCl3 used here as a Lewis acid. The last step, characterized by the
Graphical Abstract
Figure 1: Fragments produced by the FAB–MS of dehydrokuanoniamine B (20) [42].
Figure 2: Fragments produced by the EIMS of sagitol (26) [55].
Figure 3: Fragments produced by the EIMS of styelsamine B (4) [45].
Figure 4: Fragments produced by the EIMS of styelsamine D (6) [45].
Figure 5: Fragments produced by the EIMS of subarine (37) [40].
Scheme 1: Synthesis of styelsamine B (4) and cystodytin J (1) [58].
Scheme 2: Synthesis of sebastianine A (38) and its regioisomer 39 [59].
Scheme 3: Synthesis route A of neoamphimedine (12) [61].
Scheme 4: Synthesis route B of neoamphimedine (12) [62].
Scheme 5: Synthesis of arnoamines A (40) and B (41) [63].
Scheme 6: Synthesis of ascididemin (42) [65].
Scheme 7: Synthesis of subarine (37) [66,67].
Scheme 8: Synthesis of demethyldeoxyamphimedine (9) [68].
Scheme 9: Synthesis of pyridoacridine analogues related to ascididemin (42) [70].
Scheme 10: Synthesis of analogues of meridine (56) [71].
Scheme 11: Synthesis of bulky pyridoacridine as eilatin (58) [72].
Scheme 12: Synthesis of AK37 (59), analogue of kuanoniamine A (60) [73].
Figure 6: Biosynthesis pathway I [74].
Figure 7: Reaction illustrating catechol and kynuramine as possible biosynthetic precursors [75].
Figure 8: Biosynthesis pathway B deduced from the feeding experiment A using labelled precursors [76].
Figure 9: Proposed biosynthesis pathway [47].
Figure 10: 4H-Pyrido[2,3,4-kl]acridin-4-one as a cytotoxic pharmacophore.
Figure 11: 7H-Pyrido[2,3,4-kl]acridine as a cytotoxic pharmacophore.
Figure 12: 9H-Quinolino[4,3,2-de][1,10]phenanthrolin-9-one as a cytotoxic pharmacophore.
Figure 13: 8H-Benzo[b]pyrido[4,3,2-de][1,7]phenanthrolin-8-one as a cytotoxic pharmacophore.
Figure 14: Pyrido[4,3,2-mn]pyrrolo[3,2,1-de]acridine as a cytotoxic pharmacophore.
Figure 15: 9H-Pyrido[4,3,2-mn]thiazolo[4,5-b]acridin-9-one and 8H-pyrido[4,3,2-mn]thiazolo[4,5-b]acridine: cyt...
Figure 16: 9H-quinolino[4,3,2-de][1,10]phenanthrolin-9-one as an anti-mycobacterial pharmacophore.
Figure 17: 9H-Quinolino[4,3,2-de][1,10]phenanthrolin-9-one as an antibacterial pharmacophore.
Figure 18: Saturated and less saturated pyridine moieties as aspartyl inhibitor cores.
Figure 19: Iminobenzoquinone and acridone cores as intercalating and TOPO inhibitor motifs found in pyridoacri...
Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols
- Bianca Rossi,
- Nadia Pastori,
- Simona Prosperini and
- Carlo Punta
Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10
- amine. General procedure for β-radical aminoalkylation of alcohols A homogeneous solution of ethanol (5 mL, for products 1l, 1m, and 1n) or CH2Cl2 (5 mL, for products 1o and 1p), containing an arylamine (2 mmol), a cyclic or acyclic ketone (5 mmol), and TiCl4 (2.5 mL of 1 M solution in CH2Cl2, 2.5 mmol
Graphical Abstract
Scheme 1: Nucleophilic radical addition to imines mediated by titanium salts.
Scheme 2: Radical domino approach to the synthesis of β-aminoacohols triggered by titanium salts.
Scheme 3: Competitive imine formation from THF.
Scheme 4: Reaction mechanism.
Scheme 5: Domino reaction in the presence of ethanol.
One-pot four-component reaction for convenient synthesis of functionalized 1-benzamidospiro[indoline-3,4'-pyridines]
- Chao Wang,
- Yan-Hong Jiang and
- Chao-Guo Yan
Beilstein J. Org. Chem. 2014, 10, 2671–2676, doi:10.3762/bjoc.10.281
- reactions [19][20][21]. Recently, we and Perumal have demonstrated that the four-component reaction of arylamine, acetylenedicarboxylate, isatin and malononitrile can afford the spiro[indoline-3,4’-pyridine] derivatives in satisfactory yields [22][23][24]. We envisioned that functionalized spiro[indoline
Graphical Abstract
Figure 1: Molecular structure of spiro[indoline-3,4'-pyridine] 1k.
Scheme 1: The dynamic equilibrium of cis/trans-conformation of spiro[indoline-3,4'-pyridine].
Scheme 2: Proposed reaction mechanism for the four-component reaction.
Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction
- László Tóth,
- Yan Fu,
- Hai Yan Zhang,
- Attila Mándi,
- Katalin E. Kövér,
- Tünde-Zita Illyés,
- Attila Kiss-Szikszai,
- Balázs Balogh,
- Tibor Kurtán,
- Sándor Antus and
- Péter Mátyus
Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272
- aromatic substitution by using 2-fluoro-5-nitrobenzaldehyde (11b) to give rac-5 containing a tertiary arylamine nitrogen in 71% yield. With the 2-chloro-5-nitrobenzaldehyde reagent, only 3% yield for rac-5 could be achieved. Subsequently rac-5 was reacted with 1,3-dimethylbarbituric acid (12), Meldrum’s
Graphical Abstract
Figure 1: Pharmacologically active derivatives 1–4 containing the 1,4-benzoxazepine moiety or its analogue.
Scheme 1: Domino Knoevenagel–[1,5]-hydride shift cyclization reaction for the preparation of condensed 1,4-be...
Scheme 2: i) a) NaN3, CF3COOH, b) H2O, Δ (77%); ii) LiAlH4, dry THF, Δ (80%); iii) 11b, K2CO3, toluene, Δ (71...
Figure 2: Lowest-energy conformers of a) trans-(2S,15aS)-7a (>99.9%) with the replacement of the N-methyl gro...
Figure 3: Lowest-energy conformers of a) cis-(2R,15aS)-7a (99.4%) with the replacement of the N-methyl groups...
Figure 4: HPLC-ECD spectra of the first-eluting (black curve) and second-eluting (red curve) enantiomers of a...
Figure 5: Protective effect of compound 7a on hydrogen peroxide-induced neurotoxicity in SH-SY5Y cells. ##P <...
Figure 6: Protective effect of compound 7b on β-amyloid25–35-induced neurotoxicity in SH-SY5Y cells. ##P < 0....
Multicomponent reactions in nucleoside chemistry
- Mariola Koszytkowska-Stawińska and
- Włodzimierz Buchowicz
Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179
- rather limited. Zhang et al. obtained a series of pyrimidine nucleoside-thazolidinone hybrids 15 from 5-formyl-3',5'-di-O-acetyl-2'-deoxyuridine (14), an arylamine and mercaptoacetic acid (Scheme 6) [65]. The reactions were performed in a ionic liquid ([bmim]PF6). Products 15 were obtained in good to
Graphical Abstract
Figure 1: Selected chemical modifications of natural ribose or 2'-deoxyribose nucleosides leading to the deve...
Scheme 1: (a) Classical Mannich reaction; (b) general structures of selected hydrogen active components and s...
Scheme 2: Reagents and reaction conditions: i. H2O or H2O/EtOH, 60–100 °C, 7 h–10 d; ii. H2, Pd/C or PtO2; ii...
Scheme 3: Reagents and reaction conditions: i. H2O, 90 °C, overnight.
Scheme 4: Reagents and reaction conditions: i. AcOH, H2O, 60 °C, 12 h-5 d; ii. AcOH, H2O, 60 °C, 8 h.
Scheme 5: Reagents and reaction conditions: i. CuBr, THF, reflux, 0.5 h; ii. n-Bu4NF·3H2O, THF, rt, 2 h.
Scheme 6: Reagents and reaction conditions: i. [bmim][PF6], 80 °C, 5–8 h.
Scheme 7: Reagents and reaction conditions: i. EtOH, reflux, 24 h.
Scheme 8: Reagents and reaction conditions: i. NaOAc, H2O, 95 °C, 1–16 h; ii. NaOAc, H2O, 95 °C, 1 h.
Scheme 9: Reagents and reaction conditions: i. a. 37% aq HCl, MeOH; b. NaOAc, 1,4-dioxane, H2O, 100 °C, overn...
Scheme 10: Reagents and reaction conditions: i. DMAP, DCC, MeOH, rt, 1 h.
Scheme 11: The Kabachnik–Fields reaction.
Scheme 12: Reagents and reaction conditions: i. 60 °C, 3 h; ii. 80 °C, 2 h.
Scheme 13: The four-component Ugi reaction.
Scheme 14: Reagents and reaction conditions: i. MeOH, rt, 2–3 d, yields not given.
Scheme 15: Reagents and reaction conditions: i. MeOH/CH2Cl2 (1:1), rt, 24 h, yield not given; ii. 6 N aq HCl, ...
Scheme 16: Reagents and reaction conditions: i. MeOH/H2O, rt, 26 h; ii. aq AcOH, reflux, 50%; iii. reversed ph...
Scheme 17: Reagents and reaction conditions: i. MeOH, rt, 24 h; ii. HCl, MeOH, 0 °C to rt, 6 h, then H2O, rt, ...
Scheme 18: Reagents and reaction conditions: i. DMF/Py/MeOH (1:1:1), rt, 48 h; ii. 10% HCl/MeOH, rt, 30 min.
Scheme 19: Reagents and reaction conditions (R = CH3 or H): i. CH2Cl2/MeOH (2:1), 35–40 °C, 2 d; ii. HF/pyridi...
Scheme 20: Reagents and reaction conditions: i. MeOH, 76%; ii. 80% aq TFA, 100%.
Scheme 21: Reagents and reaction conditions: i. EtOH, rt, 72 h; ii. Zn, aq NaH2PO4, THF, rt, 1 week; then 80% ...
Scheme 22: Reagents and reaction conditions: i. EtOH, rt, 48 h, then silica gel chromatography, 33% for 57 (30...
Scheme 23: Reagents and reaction conditions: i. [bmim]BF4, 80 °C, 4 h; ii. [bmim]BF4, 80 °C, 3 h; iii. [bmim]BF...
Scheme 24: Reagents and reaction conditions: i. [bmim]BF4, 80 °C.
Scheme 25: Reagents and reaction conditions: i. H3PW12O40 (2 mol %), EtOH, 50 °C, 2–15 h; ii. H3PW12O40 (2 mol...
Scheme 26: General scheme of the Biginelli reaction.
Scheme 27: Reagents and reaction conditions: i. EtOH, reflux.
Scheme 28: Reagents and reaction conditions: i. Bu4N+HSO4−, diethylene glycol, 120 °C, 1.5–3 h.
Scheme 29: Reagents and reaction conditions: i. BF3·Et2O, CuCl, AcOH, THF, 65 °C, 24 h; ii. Yb(OTf)3, THF, ref...
Scheme 30: Reagents and reaction conditions: TCT (10 mol %), rt: i. 100 min; ii. 150 min; iii. 140 min.
Scheme 31: Reagents and reaction conditions: i. EtOH, microwave irradiation (300 W), 10 min; ii. EtOH, 75 °C, ...
Scheme 32: The Hantzsch reaction.
Scheme 33: Reagents and reaction conditions: TCT (10 mol %), rt, 80–150 min.
Scheme 34: Reagents and reaction conditions: i. Yb(OTf)3, THF, 90 °C, 12 h; ii. 4 Å molecular sieves, EtOH, 90...
Scheme 35: Reagents and reaction conditions: i. MeOH, 50 °C, 48 h.
Scheme 36: Reagents and reaction conditions: i. MeOH, 25 °C, 5 d.
Scheme 37: Bu4N+HSO4−, diethylene glycol, 80 °C, 1–2 h.
Scheme 38: The three-component carbopalladation of dienes on the example of buta-1,3-diene.
Scheme 39: Reagents and reaction conditions: i. 5 mol % Pd(dba)2, Bu4NCl, ZnCl2, acetonitrile or DMSO, 80 °C o...
Scheme 40: Reagents and reaction conditions: i. 2.5 mol % Pd2(dba)3, tris(2-furyl)phosphine, K2CO3, MeCN or DM...
Scheme 41: Reagents and reaction conditions: i. 2.5 mol % Pd2(dba)3, tris(2-furyl)phosphine, K2CO3, MeCN or DM...
Scheme 42: The three-component Bucherer–Bergs reaction.
Scheme 43: Reagents and reaction conditions: i. MeOH, H2O, 70 °C, 4.5 h; ii. (1) H2, 5% Pd/C, MeOH, 55 °C, 5 h...
Scheme 44: Reagents and reaction conditions: i. pyridine, MgSO4, 100 °C, 28 h, N2; ii. DMF, 70–90 °C, 22–30 h,...
Scheme 45: Reagents and reaction conditions: i. Montmorillonite K-10 clay, microwave irradiation (600 W), 6–10...
Scheme 46: Reagents and reaction conditions: i. Montmorillonite K-10 clay, microwave irradiation (560 W), 6–10...
Scheme 47: Reagents and reaction conditions: i. CeCl3·7H2O (20 mol %), NaI (20 mol %), microwave irradiation (...
Scheme 48: Reagents and reaction conditions: i. PhI(OAc)2 (3 mol %), microwave irradiation (45 °C), 6–9 min.
Scheme 49: Reagents and reaction conditions: i. 117, ethyl pyruvate, TiCl4, dichloromethane, −78 °C, 1 h; then ...
Chemistry of polyhalogenated nitrobutadienes, 14: Efficient synthesis of functionalized (Z)-2-allylidenethiazolidin-4-ones
- Viktor A. Zapol’skii,
- Jan C. Namyslo,
- Mimoza Gjikaj and
- Dieter E. Kaufmann
Beilstein J. Org. Chem. 2014, 10, 1638–1644, doi:10.3762/bjoc.10.170
- -thioperchlorobuta-1,3-diene [16][45]. However, our novel ring closing reaction incorporates an arylamine as source for the nitrogen of the thiazolidin-4-one heterocycle. Results and Discussion The reaction of pentachloro-2-nitro-1,3-butadiene (1) with 1.1 equivalents of ethyl 2-mercaptoacetate (2) at room
Graphical Abstract
Scheme 1: SNVin reactions of pentachloro-2-nitro-1,3-butadiene (1).
Scheme 2: Formation of thiazolidin-4-ones 7–19.
Figure 1: Hindered rotation in the case of ortho- or meta-substituted aniline precursors.
Figure 2: X-ray analysis of thiazolidin-4-one 11.
Scheme 3: Assumed mechanism for the formation of thiazolidin-4-ones 7–18.
Scheme 4: Substitution reactions of the precursors 3 and 5 with additional amines.
Scheme 5: Synthesis of 5-arylmethylidenethiazolidin-4-ones 22–26 and 1H-pyrazoles 27, 28.
Scheme 6: Assumed mechanism for the formation of 1H-pyrazole 27.
Scheme 7: Formation of ethyl propanoate 29 and subsequent reactions.
