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Search for "quinolin" in Full Text gives 42 result(s) in Beilstein Journal of Organic Chemistry.
Chemical and biosynthetic potential of Penicillium shentong XL-F41
- Ran Zou,
- Xin Li,
- Xiaochen Chen,
- Yue-Wei Guo and
- Baofu Xu
Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52
- substructure at C-14 with a methine at C-16, indicated by the methoxy group. The position of the methoxy substituent was established by HMBC correlations, and the 13C NMR data suggested that compound 1 includes a 4-oxo-2,3-dihydro-(1H)-quinolin-3-yl fragment. The planar structure was established from HMBC
Graphical Abstract
Figure 1: HPLC analysis of small-scale fermentation with different media. More details of media, XISR I and X...
Figure 2: Chemical structures of compounds 1–12.
Figure 3: Key 2D NMR correlations of compounds 1–3.
Figure 4: Experimental and calculated ECD spectra at the CAM-B3LYP/6-311G(d,p) level of theory for compound 1....
Figure 5: Biosynthetic exploration of compounds 1 and 2. A: The schematic presents the biosynthetic gene clus...
Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides
- Changdong Shao,
- Chen Ma,
- Li Li,
- Jingyi Liu,
- Yanan Shen,
- Chen Chen,
- Qionglin Yang,
- Tianyi Xu,
- Zhengsong Hu,
- Yuhe Kan and
- Tingting Zhang
Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14
- reaction of 8-aminoquinoline amides using activated and unactivated alkyl bromides as the bromine source (Scheme 1, reaction 4). Results and Discussion At the beginning of this investigation, N-(quinolin-8-yl)benzamide (1a) and ethyl bromoacetate (2a) were selected as model substrates to screen the
- highly efficient C5-bromination protocol has been established. Having identified the optimal reaction conditions for the bromination of N-(quinolin-8-yl)benzamide (1a) with ethyl bromoacetate (2a) (Table 1, entry 12), we next examined the substrate scope and limitations of our method with an array of 8
Graphical Abstract
Scheme 1: Methods for the C5-selective bromination of 8-aminoquinoline amides.
Scheme 2: Substrate scope of the 8-aminoquinoline amides. Reaction conditions: 1 (0.2 mmol), 2a (0.8 mmol), C...
Scheme 3: Substrate scope of the bromoalkanes. Reaction conditions: 1a (0.2 mmol), 2 (0.8 mmol), Cu(OAc)2·H2O...
Scheme 4: Further substrate scope investigations and gram-scale application.
Scheme 5: Control experiments and proposed mechanism.
Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors
- Yordanka Mollova-Sapundzhieva,
- Plamen Angelov,
- Danail Georgiev and
- Pavel Yanev
Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132
- sensing; Introduction Among the vast number of biologically active quinoline derivatives [1][2], the subclass of 4-quinolones (also referred to as 4-oxo-1,4-dihydroquinolines, quinolin-4(1H)-ones, or 4-hydroxyquinolines) is of great importance with its rich variety of bioactive compounds. Perhaps the
Graphical Abstract
Scheme 1: Preparation of α-(o-nitrobenzoyl)-β-enamino amides 3. Reagents and conditions: i) EtNH2 (70% aq, 1....
Scheme 2: Alternative manipulations of intermediates 3, leading to either 2-alkyl-4-quinolones 8 (via enamino...
Selectivity control towards CO versus H2 for photo-driven CO2 reduction with a novel Co(II) catalyst
- Lisa-Lou Gracia,
- Philip Henkel,
- Olaf Fuhr and
- Claudia Bizzarri
Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129
- complex obtainable via a straightforward synthesis, with improved solubility, concerning our previous Co(II) complexes [21]. Thus, the new Co(II) complex bears two 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole (BzQuTr) units, that were obtained through a copper-catalyzed alkyne–azide cycloaddition (CuAAC
- maintaining high selectivity for carbon products. Results and Discussion Synthesis and characterization of the new Co(II)-based catalyst The novel cobalt(II) complex 1 was synthesized in dry methanol (MeOH) by mixing in a 2:1 ratio, the chelating diimine ligand, 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole
Graphical Abstract
Figure 1: Chemical structures of the molecular components used in this work: Co(II) complex 1 as the novel ca...
Figure 2: ORTEP drawing of crystal polymorph 1a (left) and 1b (right), shown at the 50% probability level. Hy...
Figure 3: UV–vis absorbance of complex 1 in DMA. Inset: zoom-in of the 500–800 nm range to visualize the low-...
Figure 4: Cyclic voltammetry of complex 1 in 0.1 M TBAPF6 solution of (a) DMA and (b) DMA/TEOA 5:1 (v/v). Bla...
Figure 5: Time evolution of CO (blue squares) and H2 (red triangles) with the power functional fitting (blue ...
Scheme 1: Proposed mechanism for the photoinduced reduction of carbon dioxide with the system presented in th...
One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles
- Juan Lu,
- Bin Yao,
- Desheng Zhan,
- Zhuo Sun,
- Yun Ji and
- Xiaofeng Zhang
Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171
- UMB32 and UMB136 [33][34]. Zhang developed 4-aminoquinolines for the synthesis of fluorinated analogues of acetylcholinesterase (AChE) inhibitors [35] in cascade reactions, such as one-step syntheses of quinolines. Quinolin-4-ols involving histone acetyltransferases (HAT) inhibitors [36][37], as well as
Graphical Abstract
Scheme 1: The diastereoselective synthesis of spirooxindoles through MCRs.
Figure 1: Bioactive Spirooxindole-pyrrolothiazoles.
Scheme 2: The synthesis of spirooxindolepyrrolothiazoles.
Scheme 3: Four-component reaction for the synthesis of compound 5.
Scheme 4: Proposed mechanism for the double [3 + 2] cycloadditions.
Scheme 5: The synthesis of compound 5a with ᴅ- and ʟ-cysteine.
Scheme 6: Two-step (process A) vs cascade (process B) synthesis of 5a. i) 1.0:1.15 of 1a/2, EtOH (0.05 M), 25...
Figure 2: Graphical representation of the green metrics (AE, AEf, CE, RME, OE and MP) analysis for processes ...
Figure 3: Graphical representation of the green metrics (PMI, E-factor, and SI) analysis for processes A and ...
Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode
- Ettore Crovini,
- Zhen Zhang,
- Yu Kusakabe,
- Yongxia Ren,
- Yoshimasa Wada,
- Bilal A. Naqvi,
- Prakhar Sahay,
- Tomas Matulaitis,
- Stefan Diesing,
- Ifor D. W. Samuel,
- Wolfgang Brütting,
- Katsuaki Suzuki,
- Hironori Kaji,
- Stefan Bräse and
- Eli Zysman-Colman
Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197
- )) (10 nm)/X wt % DICzTRZ or ICzTRZ: CzSi (20 nm)/PPF (2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan) (5 nm)/TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene) (50 nm)/Liq (lithium quinolin-8-olate) (1 nm)/Al (80 nm), where X is 20 or 30. The PVK layer is applied to facilitate hole injection from
Graphical Abstract
Figure 1: Molecular structures of emitters.
Figure 2: a) Molecular structure and b) optimized DFT-calculated geometry of DICzTRZ. Hydrogen atoms are omit...
Figure 3: HOMO, HOMO–1 (H–1), LUMO, and LUMO+1 (L+1) electron density distributions (isovalue: 0.02) and ener...
Figure 4: a) Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) of DICzTRZ in DCM (scan rate = ...
Figure 5: a) Prompt and b) delayed time-resolved decay in spin-coated 20 wt % CzSi film of DICzTRZ (λexc = 37...
Figure 6: Angle-resolved photoluminescence measurement of a solution-processed film of 20 wt % DICzTRZ in CzS...
Figure 7: Device characteristics of 20 and 30 wt % DICzTRZ-based OLEDs, which are represented by red and blue...
Figure 8: Device efficiency simulation of the fabricated OLEDs depicting the variation in EQE with varied PL ...
Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases
- Inaiá O. Rocha,
- Yuri G. Kappenberg,
- Wilian C. Rosa,
- Clarissa P. Frizzo,
- Nilo Zanatta,
- Marcos A. P. Martins,
- Isadora Tisoco,
- Bernardo A. Iglesias and
- Helio G. Bonacorso
Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191
- , Brazil Laboratório de Bioinorgânica e Materiais Porfirínicos, Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil 10.3762/bjoc.17.191 Abstract A new series of ten examples of Schiff bases, namely (E)-2-(((2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl)quinolin-6
- (Scheme 1). Results and Discussion Chemistry The synthetic routes and structures for the synthesis of (E)-2-(((2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl)quinolin-6-yl)imino)methyl)phenols 3 are collected in Scheme 2 and Scheme 3. First, a series of six 6-amino-2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl
- reaction (TLC) and cooling the mixture to room temperature, the solid was filtered under reduced pressure. The crude compounds 3 were purified by recrystallization from ethanol to provide the desired (E)-2-(((4-(trifluoromethyl)quinolin-6-yl)imino)methyl) phenols 3 in 20–91% yield. Spectral data (E)-2-(((2
Graphical Abstract
Figure 1: Examples of structures and properties of Schiff bases of interest in the present study.
Scheme 1: General view for the present study.
Scheme 2: Synthesis of ((trifluoromethyl)quinolinyl)phenol Schiff bases 3aa–fa.
Scheme 3: Synthesis of trifluoromethylated quinolinyl-phenol Schiff bases 3bb–be.
Figure 2: ORTEP diagram of the crystal structure of (E)-2-(((2-phenyl-4-(trifluoromethyl)quinolin-6-yl)imino)...
Figure 3: Normalized absorption spectra in the UV–vis region of compounds (a) 3ea and (b) 3be in CHCl3, MeOH ...
Figure 4: Normalized steady-state fluorescence emission spectra of compound 3aa (R = Ph, R1 = H) in CHCl3 (bl...
Figure 5: Comparative normalized steady-state fluorescence emission spectra of compounds 3bb and 3be in the t...
Figure 6: Photostability (%) plots of derivatives 3aa–fa and 3bb–be in DMSO solution after irradiation with w...
Figure 7: DPBF photooxidation assays by red-light irradiation with diode laser (λ = 660 nm) in the presence o...
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.
Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties
- Anka Utama Putra,
- Deniz Çakmaz,
- Nurgül Seferoğlu,
- Alberto Barsella and
- Zeynel Seferoğlu
Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189
- all dyes 3–7 which was collected by filtration and recrystallized from ethanol to obtain the pure dyes. ((E)-2-(1-(4-Aminophenyl)-3-(2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)allylidene)malononitrile) (3) Dark purple solid; yield: 64%; mp 236–238 °C; FTIR (cm−1): 3441, 3349, 3224, 2920
- recrystallized from ethanol to obtain the pure dyes. (2-((E)-1-(4-(((E)-2-Hydroxybenzylidene)amino)phenyl)-3-(2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)allylidene)malononitrile) (8) Dark purple solid; yield 94%; mp 202–203 °C; FTIR (cm−1): 3479 (broad), 3062, 2943, 2835, 2208, 1614, 1560, 1510
Graphical Abstract
Scheme 1: Synthetic pathways of dyes 3–7 and Schiff base analogs 8–12.
Figure 1: The optimized geometry of dyes 3 and 8.
Figure 2: Absorption spectra of dyes 3 (a, left) and 8 (b, right). Inset: Color of dyes 3 and 8 in the given ...
Figure 3: Emission spectra of dyes 3 (a, left) and 8 (b, right). Inset: Color of dyes 3 and 8 in the indicate...
Figure 4: Red shift phenomena with changing substituents in absorption (a, left) and emission (b, right) spec...
Figure 5: Absorption (a, left) and emission (b, right) change of dye 12 upon addition of 15 equiv of TBAOH an...
Figure 6: Photographs of dye 12 (left, ambient light), without, after the addition of 15 equiv of TBAOH (midd...
Figure 7: Absorption (a, left) and emission (b, right) change of 8 in Britton–Robinson buffer solutions at di...
Figure 8: Photographs of dye 8 in Britton–Robinson buffer solutions at different pH values.
Figure 9: Sigmoid function obtained from dye 8 UV–vis absorption spectra during pH investigation.
Figure 10: TGA curves of all synthetized dyes.
When metal-catalyzed C–H functionalization meets visible-light photocatalysis
- Lucas Guillemard and
- Joanna Wencel-Delord
Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147
- perfluoroalkyl benzoic acid derivatives. A plausible mechanism for the perfluoroalkylation of N-(quinolin-8-yl)benzamides is proposed in Figure 34. First, C–H activation of the benzamide substrate with copper produces a cyclometalated complex. Meanwhile, perfluoroalkyl radicals are generated by electron transfer
Graphical Abstract
Figure 1: Concept of dual synergistic catalysis.
Figure 2: Classification of catalytic systems involving two catalysts.
Figure 3: General mechanism for the dual nickel/photoredox catalytic system.
Figure 4: General mechanisms for C–H activation catalysis involving different reoxidation strategies.
Figure 5: Indole synthesis via dual C–H activation/photoredox catalysis.
Figure 6: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 7: Oxidative Heck reaction on arenes via the dual catalysis.
Figure 8: Proposed mechanism for the Heck reaction on arenes via dual catalysis.
Figure 9: Oxidative Heck reaction on phenols via the dual catalysis.
Figure 10: Proposed mechanism for the Heck reaction on phenols via dual catalysis.
Figure 11: Carbazole synthesis via dual C–H activation/photoredox catalysis.
Figure 12: Proposed mechanism for the carbazole synthesis via dual catalysis.
Figure 13: Carbonylation of enamides via the dual C–H activation/photoredox catalysis.
Figure 14: Proposed mechanism for carbonylation of enamides via dual catalysis.
Figure 15: Annulation of benzamides via the dual C–H activation/photoredox catalysis.
Figure 16: Proposed mechanism for the annulation of benzamides via dual catalysis.
Figure 17: Synthesis of indoles via the dual C–H activation/photoredox catalysis.
Figure 18: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 19: General concept of dual catalysis merging C–H activation and photoredox catalysis.
Figure 20: The first example of dual catalysis merging C–H activation and photoredox catalysis.
Figure 21: Proposed mechanism for the C–H arylation with diazonium salts via dual catalysis.
Figure 22: Dual catalysis merging C–H activation/photoredox using diaryliodonium salts.
Figure 23: Direct arylation via the dual catalytic system reported by Xu.
Figure 24: Direct arylation via dual catalytic system reported by Balaraman.
Figure 25: Direct arylation via dual catalytic system reported by Guo.
Figure 26: C(sp3)–H bond arylation via the dual Pd/photoredox catalytic system.
Figure 27: Acetanilide derivatives acylation via the dual C–H activation/photoredox catalysis.
Figure 28: Proposed mechanism for the C–H acylation with α-ketoacids via dual catalysis.
Figure 29: Acylation of azobenzenes via the dual catalysis C–H activation/photoredox.
Figure 30: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 31: Proposed mechanism for the C2-acylation of indoles with aldehydes via dual catalysis.
Figure 32: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 33: Perfluoroalkylation of arenes via the dual C–H activation/photoredox catalysis.
Figure 34: Proposed mechanism for perfluoroalkylation of arenes via dual catalysis.
Figure 35: Sulfonylation of 1-naphthylamides via the dual C–H activation/photoredox catalysis.
Figure 36: Proposed mechanism for sulfonylation of 1-naphthylamides via dual catalysis.
Figure 37: meta-C–H Alkylation of arenes via visible-light metallaphotocatalysis.
Figure 38: Alternative procedure for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 39: Proposed mechanism for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 40: C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 41: Proposed mechanism for C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 42: Undirected C–H aryl–aryl cross coupling via dual gold/photoredox catalysis.
Figure 43: Proposed mechanism for the undirected C–H aryl–aryl cross-coupling via dual catalysis.
Figure 44: Undirected C–H arylation of (hetero)arenes via dual manganese/photoredox catalysis.
Figure 45: Proposed mechanism for the undirected arylation of (hetero)arenes via dual catalysis.
Figure 46: Photoinduced C–H arylation of azoles via copper catalysis.
Figure 47: Photo-induced C–H chalcogenation of azoles via copper catalysis.
Figure 48: Decarboxylative C–H adamantylation of azoles via dual cobalt/photoredox catalysis.
Figure 49: Proposed mechanism for the C–H adamantylation of azoles via dual catalysis.
Figure 50: General mechanisms for the “classical” (left) and Cu-free variant (right) Sonogoshira reaction.
Figure 51: First example of a dual palladium/photoredox catalysis for Sonogashira-type couplings.
Figure 52: Arylation of terminal alkynes with diazonium salts via dual gold/photoredox catalysis.
Figure 53: Proposed mechanism for the arylation of terminal alkynes via dual catalysis.
Figure 54: C–H Alkylation of alcohols promoted by H-atom transfer (HAT).
Figure 55: Proposed mechanism for the C–H alkylation of alcohols promoted by HAT.
Figure 56: C(sp3)–H arylation of latent nucleophiles promoted by H-atom transfer.
Figure 57: Proposed mechanism for the C(sp3)–H arylation of latent nucleophiles promoted by HAT.
Figure 58: Direct α-arylation of alcohols promoted by H-atom transfer.
Figure 59: Proposed mechanism for the direct α-arylation of alcohols promoted by HAT.
Figure 60: C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 61: Proposed mechanism for the C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 62: C–H functionalization of nucleophiles via excited ketone/nickel dual catalysis.
Figure 63: Proposed mechanism for the C–H functionalization enabled by excited ketones.
Figure 64: Selective sp3–sp3 cross-coupling promoted by H-atom transfer.
Figure 65: Proposed mechanism for the selective sp3–sp3 cross-coupling promoted by HAT.
Figure 66: Direct C(sp3)–H acylation of amines via dual Ni/photoredox catalysis.
Figure 67: Proposed mechanism for the C–H acylation of amines via dual Ni/photoredox catalysis.
Figure 68: C–H hydroalkylation of internal alkynes via dual Ni/photoredox catalysis.
Figure 69: Proposed mechanism for the C–H hydroalkylation of internal alkynes.
Figure 70: Alternative procedure for the C–H hydroalkylation of ynones, ynoates, and ynamides.
Figure 71: Allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 72: Proposed mechanism for the allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 73: Asymmetric allylation of aldehydes via dual Cr/photoredox catalysis.
Figure 74: Proposed mechanism for the asymmetric allylation of aldehydes via dual catalysis.
Figure 75: Aldehyde C–H functionalization promoted by H-atom transfer.
Figure 76: Proposed mechanism for the C–H functionalization of aldehydes promoted by HAT.
Figure 77: Direct C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 78: Proposed mechanism for the C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 79: Direct C–H trifluoromethylation of strong aliphatic bonds promoted by HAT.
Figure 80: Proposed mechanism for the C–H trifluoromethylation of strong aliphatic bonds.
Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts
- Soundararajan Karthikeyan,
- Radha Krishnan Shobana,
- Kamarajapurathu Raju Subimol,
- J. Helen Ratna Monica and
- Ayyanoth Karthik Krishna Kumar
Beilstein J. Org. Chem. 2020, 16, 1579–1587, doi:10.3762/bjoc.16.130
- -lactams [6], quinolin-5-ones [7], spirobisglutarimides [8], indolizines [9], and spiro carbocyclic frameworks [10]. However, most of the reported synthetic transformations utilize either allylic hydroxy-protected or allyl halide-substituted MBH adducts [11][12][13][14][15][16][17][18][19][20][21][22][23
Graphical Abstract
Scheme 1: Literature-reported cycloaddition reactions of MBH acetates involving azides and alkynes [24-28].
Scheme 2: Synthetic methodologies for triazolations of MBH adducts. a) Literature-reported indirect triazolat...
Scheme 3: Scope of the one-pot cascade reaction of the unprotected Morita–Baylis–Hillman adducts 3a–q.
Figure 1: Proposed mechanism for the synthesis of 1,4-disubstituted triazoles.
Scheme 4: Comparative analysis of the sequential one-pot reaction.
Figure 2: Proposed mechanism for the synthesis of 3-(bromomethyl)coumarins.
Synthesis and anticancer activity of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides: the copper-catalyzed tandem C–H selenation of 2-arylimidazo[1,2-a]pyridine with selenium
- Mio Matsumura,
- Tsutomu Takahashi,
- Hikari Yamauchi,
- Shunsuke Sakuma,
- Yukako Hayashi,
- Tadashi Hyodo,
- Tohru Obata,
- Kentaro Yamaguchi,
- Yasuyuki Fujiwara and
- Shuji Yasuike
Beilstein J. Org. Chem. 2020, 16, 1075–1083, doi:10.3762/bjoc.16.94
- variety of methods [14][15], and many of the targets exhibited biological activity (Figure 1). For example, bis(2-pyridyl) diselenide I has the potential to mitigate oxidative stress and inhibits the AChE activity [16], bis(quinolin-8-yl) diselenide (II) exhibited antioxidant activity in a skin cell model
Graphical Abstract
Figure 1: Biologically active selenides and diselenides having heteroaryl groups.
Figure 2: Ortep drawings of 2a (a and b) and 3a (c and d, thermal elipsoids indicate 50% probability).
Figure 3: The synthesis of bis(2-arylimidazopyridin-3-yl) diselenides. Reaction conditions: 1 (2 mmol), Se (2...
Figure 4: The synthesis of bis(2-arylimidazopyridin-3-yl) selenides. Reaction conditions: 1 (2 mmol), Se (1 m...
Scheme 1: Control reactions.
Scheme 2: Proposed mechanism (1).
Scheme 3: Proposed mechanism (2).
Figure 5: The cytotoxic effect of the bis(2-arylimidazo[1,2-a]pyridin-3-yl) diselenides 2 and selenides 3 on ...
Figure 6: The cytotoxic effect of the bis[2-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl] diselenide 2f on can...
Figure 7: Cytotoxic effect of the bis[2-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl] diselenide 2f on a cance...
Regioselective Pd-catalyzed direct C1- and C2-arylations of lilolidine for the access to 5,6-dihydropyrrolo[3,2,1-ij]quinoline derivatives
- Hai-Yun Huang,
- Haoran Li,
- Thierry Roisnel,
- Jean-François Soulé and
- Henri Doucet
Beilstein J. Org. Chem. 2019, 15, 2069–2075, doi:10.3762/bjoc.15.204
- containing two different aryl groups at α- and β-positions via sequential Pd-catalyzed C–H bond functionalization steps was studied (Scheme 4). The reaction of 1 equiv of 4-(5,6-dihydropyrrolo[3,2,1-ij]quinolin-2-yl)benzonitrile 2 and 1.5 equiv of a set of aryl bromides using again 2 mol % PdCl(C3H5)(dppb
- , the use of a longer reaction time (48 h) allowed to reach an almost complete conversion of 2, and the carbazole 27 was isolated in 62% yield. A slightly lower yield in the carbazole 28 was obtained from (4-(5,6-dihydropyrrolo[3,2,1-ij]quinolin-2-yl)phenyl)(phenyl)methanone 5 and 1,2-dibromobenzene
Graphical Abstract
Figure 1: Structures of lilolidine, tivantinib and tarazepide.
Scheme 1: Access to α- and β-arylated lilolidine derivatives.
Scheme 2: Synthesis of α-arylated lilolidine derivatives.
Scheme 3: Synthesis of α,β-di(hetero)arylated lilolidine derivatives.
Scheme 4: Synthesis of α,β-diarylated lilolidine derivatives via successive direct arylations.
Scheme 5: Synthesis of 5,6-dihydrodibenzo[a,c]pyrido[3,2,1-jk]carbazoles via successive direct arylations.
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.
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
- Bebq2 host were employed instead, where Bebq2 is bis(benzo[h]quinolin-10-olato-κN,κO)beryllium(II). In spite of that, much lower LT97 values were observed most likely due to a higher charge and exciton concentration in the host layer at such low doping concentration. Such compound represents the most
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...
Two new 2-alkylquinolones, inhibitory to the fish skin ulcer pathogen Tenacibaculum maritimum, produced by a rhizobacterium of the genus Burkholderia sp.
- Dandan Li,
- Naoya Oku,
- Atsumi Hasada,
- Masafumi Shimizu and
- Yasuhiro Igarashi
Beilstein J. Org. Chem. 2018, 14, 1446–1451, doi:10.3762/bjoc.14.122
- -1 Yanagido, Gifu 501-1193, Japan 10.3762/bjoc.14.122 Abstract Exploration of rhizobacteria of the genus Burkholderia as an under-tapped resource of bioactive molecules resulted in the isolation of two new antimicrobial 2-alkyl-4-quinolones. (E)-2-(Hept-2-en-1-yl)quinolin-4(1H)-one (1) and (E)-2
- -(non-2-en-1-yl)quinolin-4(1H)-one (3) were isolated from the culture broth of strain MBAF1239 together with four known alkylquinolones (2 and 4–6), pyrrolnitrin (7), and BN-227 (8). The structures of 1 and 3 were unambiguously characterized using NMR spectroscopy and mass spectrometry. Compounds 1–8
- ) [15] (Figure 3). Thus, the structure of 3 was concluded to be (E)-2-(non-2-en-1-yl)quinolin-4(1H)-one. The molecular ions of 1 were observed at m/z 242 and m/z 240 in the positive and negative modes, respectively, revealing a 28 Da smaller molecular weight for 1 relative to 3. The 1H NMR spectra of
Graphical Abstract
Figure 1: Structures of compounds 1–8.
Figure 2: Key COSY (bold line) and HMBC (arrow) correlations for 3.
Figure 3: Referential 13C chemical shifts of an allylic carbon in burkholone [14] and haplacutine F [15].
[3 + 2]-Cycloaddition reaction of sydnones with alkynes
- Veronika Hladíková,
- Jiří Váňa and
- Jiří Hanusek
Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113
- -2-yl, quinolin-2-yl, 5,6-dihydro-4H-1,3-oxazin-2-yl). Such sydnones reacted with potassium 2-substituted acetylene trifluoroborates under boron trifluoride diethyl etherate catalysis to give corresponding pyrazolo[3',4':4,5][1,2]azaborolo[2,3-a]pyridin-5-ium-4-uides (or quinolin-5-ium-4-uide) in
Graphical Abstract
Scheme 1: Thermal reaction of sydnones with symmetrical alkynes.
Scheme 2: Reaction of sydnones with strained cycloalkynes.
Scheme 3: Reaction of sydnones with didehydrobenzenes.
Scheme 4: Formation of isomeric pyrazole dicarboxylates.
Scheme 5: Mechanism of thermal cycloaddition between sydnones and alkynes.
Scheme 6: Mechanism of photochemical reaction of sydnones with symmetrical alkynes.
Scheme 7: HOMO–LUMO diagram for thermal [3 + 2]-cycloaddition of sydnones with alkynes.
Scheme 8: Synthetic strategy leading to 1,2-disubstituted pyrazoles.
Scheme 9: Unsuccessful reaction with phenylpropiolic acid.
Scheme 10: Synthetic strategy leading to 1,4,5-trisubstituted pyrazoles.
Scheme 11: Reaction of sydnones carrying in position 4- six-membered 2-N-heterocyclic ring.
Scheme 12: Strain-promoted sydnone alkyne cycloaddition (SPSAC).
Scheme 13: Synthesis of a key intermediate of niraparib.
Scheme 14: Reaction of sydnones with 1,3-/1,4-benzdiyne equivalents.
Scheme 15: Reaction of sydnones with heterocyclic strained cycloalkynes.
Scheme 16: Mono-copper catalyzed cycloaddition reaction.
Scheme 17: Di-copper catalyzed cycloaddition reaction.
Halogen-containing thiazole orange analogues – new fluorogenic DNA stains
- Aleksey A. Vasilev,
- Meglena I. Kandinska,
- Stanimir S. Stoyanov,
- Stanislava B. Yordanova,
- David Sucunza,
- Juan J. Vaquero,
- Obis D. Castaño,
- Stanislav Baluschev and
- Silvia E. Angelova
Beilstein J. Org. Chem. 2017, 13, 2902–2914, doi:10.3762/bjoc.13.283
- -Chloro-1-methyl-4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium iodide (TO-7Cl) Procedures A1 and A2: 2,3-Dimethylbenzo[d]thiazolium methyl sulfate (2a, 1 mmol) and the appropriate 4,7-dichloro-1-methylquinolinium methyl sulfate (4a, 1 mmol) were finely ground together in a mortar and the
- , 1450, 1370, 1315, 1110, 974, 780, 750, 725 cm−1; GC–MS (m/z): 324 (100%, [M+] − CH2Ph); elemental analysis (%) for C25H20ClIN2S Mw = 542.86, calcd for N 5.16; found: 5.53. 2-((1-Benzyl-7-(trifluoromethyl)quinolin-4(1H)-ylidene)methyl)-3-methylbenzo[d]thiazol-3-ium iodide (5b): Yield 68%; mp 284–285 °C
- ) νmax: 1600, 1520, 1450, 1455, 1375, 1325, 1280, 1210, 1150, 1120, 885, 865, 790, 725, 610, 550, 401 cm−1; GC–MS (m/z): 480 (100%, [M+] – CH2Ph); elemental analysis (%) for C25H19BrClIN2S Mw = 621.76, calcd for N, 4.51; found: 4.95. 2-((1-Benzyl-7-(trifluoromethyl)quinolin-4(1H)-ylidene)methyl)-5-bromo
Graphical Abstract
Scheme 1: Chemical structures of TO and SYBR Green I – commercial monomethine fluorescent dsDNA binders.
Scheme 2: Synthesis of the monofluoro-substituted dye TO-1F. Reagents, conditions and yields: (i) sodium meth...
Scheme 3: Synthesis of new halogen-containing analogues of TO. Reagents, conditions and yields: (i) DMS, 100 ...
Figure 1: Absorption spectra of the studied compounds in MeOH (c = 1 × 10−5 M).
Figure 2: Absorption spectra of dye 5b (c = 5 × 10−7 M) in TE buffer, in the absence and presence of dsDNA (c...
Figure 3: Fluorescence spectra of dye 5a (c = 5 × 10–7 M) in TE buffer and in the presence of increasing conc...
Figure 4: Photostability of dyes TO-7Cl and 5a–d in acetonitrile in the concentration range of 1 × 10−5 M.
Figure 5: B3LYP optimized structures.
Figure 6: Graphical representation of the frontier orbitals (isodensity plot, isovalue = 0.02 a.u.).
Figure 7: Simulated TDPBE0 spectra in methanol.
Figure 8: Electron density (isovalue = 0.002) mapped with electrostatic potential (color scheme: green for ne...
A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines
- Benedikt C. Melzer and
- Franz Bracher
Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156
- , and is of considerable pharmacological interest due to the significant cytotoxicity of numerous representatives [3]. A unique subclass of the aporphinoid alkaloids are the oxoisoaporphines (7H-dibenzo[de,h]quinolin-7-ones, e.g., menisporphine, (2)), which at the first glance appear to be not derived
Graphical Abstract
Figure 1: Prominent oxoaporphine and oxoisoaporphine alkaloids: liriodenine (1), menisporphine (2), dauriporp...
Scheme 1: Previously reported [7,17] and new approach to oxoisoaporphine alkaloids.
Scheme 2: Synthesis of iodinated isoquinolines 8a–c from alkoxy-substituted isoquinolines 7a–c.
Scheme 3: Synthesis of methyl 2-(isoquinolin-1-yl)benzoates 10a–c from 1-iodoisoquinolines 8a–c.
Scheme 4: Synthesis of the alkaloids 6-O-demethylmenisporphine (4), dauriporphinoline (5), and bianfugecine (6...
Scheme 5: Attempted synthesis of bianfugecine (6) via directed remote metalation and subsequent trapping of t...
Scheme 6: Outcome of a D2O quenching experiment after metalation of amide 12.
Scheme 7: Synthesis of 1-arylnaphthalene analogues 15 and 16.
Scheme 8: Outcome of a D2O quenching experiment after metalation of amide 16 with LDA.
Scheme 9: Synthesis of the alkaloids menisporphine (2) and dauriporphine (3) by O-methylation of the alkaloid...
A novel method for heterocyclic amide–thioamide transformations
- Walid Fathalla,
- Ibrahim A. I. Ali and
- Pavel Pazdera
Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20
- phthalizin-1-thiones C7 and C8a. Synthesis of quinolin-2-thiones C9 and quinoxalin-2-thiones C10–C13a. Supporting Information Supporting Information File 60: Additional experimental and analytical data. Acknowledgements We would like to thank the Department of Organic Chemistry, Faculty of Science, Masaryk
Graphical Abstract
Scheme 1: Synthesis of N-cyclohexyl dithiocarbamate cyclohexylammonium salt (2).
Scheme 2: The two-step thiation of quinazolin-4-one A1–6 and phthalazin-1-ones A7 and A8.
Scheme 3: Thiation of quinoline A9 and quinoxalinone A10–13.
Scheme 4: Rational mechanism of the reaction of 4-chloro-2-phenylquinazoline (B2) to 2-phenylquinazolin-4(3H)...
Direct arylation catalysis with chloro[8-(dimesitylboryl)quinoline-κN]copper(I)
- Sem Raj Tamang and
- James D. Hoefelmeyer
Beilstein J. Org. Chem. 2016, 12, 2757–2762, doi:10.3762/bjoc.12.272
- featuring an ambiphilic ligand, (quinolin-8-yl)dimesitylborane. Direct arylation could be achieved with 0.2 mol % catalyst and 3 equivalents of base (KO(t-Bu)) at 80 °C to afford TON ≈160–190 over 40 hours. Keywords: catalysis; C–C coupling; C–H activation; copper; direct arylation; Introduction Coupling
Graphical Abstract
Scheme 1: Coordination of Cu(I) with the ambiphilic ligand 1 to form the catalyst 2.
Scheme 2: Proposed mechanism of direct arylation catalyzed by 2 (X = Cl/I; Ar = aryl).
From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer
- Ming Liu,
- Jan C. Namyslo,
- Martin Nieger,
- Mika Polamo and
- Andreas Schmidt
Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264
- –Ccarbene bonds have lengths between 184.06(19) pm and 184.82(19) pm, respectively. These values correspond to literature-known bond lengths of cis arranged bidentate ligands around Ni [42][43][44], but, as expected, they differ from those of [(PEt3)(Ph)Ni(imidazo[1,5-a]quinolin-9-olate-1-ylidene)] [45] as
Graphical Abstract
Figure 1: Examples of anionic N-heterocyclic carbenes.
Scheme 1: A postulated mesomeric betaine – NHC equilibrium (6A/6B) and formation of an anionic NHC 7. Formati...
Figure 2: Molecular drawing of one of the two crystallographic independent molecules of borane adduct 8 (disp...
Figure 3: Molecular drawing of the cation of the gold complex 9 (displacement parameters are drawn at 50% pro...
Scheme 2: The anionic NHC 7 forms a rhodium complex and a nickel complex. d) [RhCl(COD)]2, toluene, rt to ref...
Figure 4: Molecular drawing of rhodium complex 11 (minor disorder parts omitted for clarity, displacement par...
Figure 5: Molecular drawing of the dimeric nickel complex 12 (displacement parameters are drawn at 50% probab...
A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring
- John Andraos
Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236
- dihydropyridine, hydantoin, imidazole, indole, isoquinoline, isoxazole, oxazole, 4H-pyran, pyrazine, pyridazine, pyridine, pyridinone, pyrimidine, pyrimidone, pyrrole, 3H-quinazolin-4-one, quinoline, 1H-quinolin-4-one, and thiophene. For heterocycles that are composed of a fused aromatic ring, such as
Graphical Abstract
Figure 1: Possible two-component couplings for various monocyclic rings frequently encountered in organic mol...
Figure 2: Possible three-component couplings for various monocyclic rings frequently encountered in organic m...
Figure 3: Possible four-component couplings for various monocyclic rings frequently encountered in organic mo...
Figure 4: Permutations of two-component coupling patterns for synthesizing the cyclohexanone ring. Synthesis ...
Figure 5: Permutations of two-component coupling patterns for synthesizing the cyclohexanone ring overlayed w...
Scheme 1: Conjectured syntheses of cyclohexanone via [5 + 1] strategies.
Scheme 2: Conjectured syntheses of cyclohexanone via [4 + 2] strategies.
Scheme 3: Conjectured syntheses of cyclohexanone via [3 + 3] strategies.
Figure 6: Permutations of three-component coupling patterns for synthesizing the cyclohexanone ring. Synthesi...
Figure 7: Permutations of three-component coupling patterns for synthesizing the pyrazole ring via [2 + 2 + 1...
Scheme 4: Literature method for constructing the pyrazole ring via the A4 [2 + 2 + 1] strategy.
Scheme 5: Literature methods for constructing the pyrazole ring via the A5 [2 + 2 + 1] strategy.
Scheme 6: Literature methods for constructing the pyrazole ring via the A1 [2 + 2 + 1] strategy.
Scheme 7: Literature methods for constructing the pyrazole ring via the B4 [3 + 1 + 1] strategy.
Figure 8: Intrinsic green performance of documented pyrazole syntheses according to [2 + 2 + 1] and [3 + 1 + ...
Scheme 8: Conjectured reactions for constructing the pyrazole ring via the A2 and A3 [2 + 2 + 1] strategies.
Scheme 9: Conjectured reactions for constructing the pyrazole ring via the B1, B2, B3, and B4 [3 + 1 + 1] str...
Figure 9: Permutations of three-component coupling patterns for synthesizing the Biginelli ring adduct. Synth...
Scheme 10: Reported syntheses of the Biginelli adduct via the traditional [3 + 2 + 1] mapping strategy.
Scheme 11: Reported syntheses of the Biginelli adduct via new [3 + 2 + 1] mapping strategies.
Scheme 12: Reported syntheses of the Biginelli adduct via a new [2 + 2 + 1 + 1] mapping strategy.
Scheme 13: Conjectured syntheses of the Biginelli adduct via new [2 + 2 + 2] mapping strategies.
Scheme 14: Conjectured syntheses of the Biginelli adduct via new [3 + 2 + 1] mapping strategies.
Figure 10: Intrinsic green performance of documented Biginelli adduct syntheses according to [3 + 2 + 1] three...
Figure 11: Intrinsic green performance of newly conjectured Biginelli adduct syntheses according to [4 + 1 + 1...
Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines
- David R. Chisholm,
- Garr-Layy Zhou,
- Ehmke Pohl,
- Roy Valentine and
- Andrew Whiting
Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174
- substituent, each with a different means of cyclisation. A versatile and stable quinolin-2-one intermediate was identified, which could be reduced to the corresponding THQ with borane reagents, or to the DHQ with diisobutylaluminium hydride via a novel elimination that is more favourable at higher
- also use Lewis acids [7]. The resultant quinolin-2-one is then reduced using strong hydride reducing agents such as LiAlH4 [8]. Similar THQs have also been prepared by a reductive Beckmann rearrangement of an oxime using diisobutylaluminium hydride (DIBAL) [9]. In contrast to this variety, the
- considered (Scheme 6). The quinolin-2-one 13 was predicted to be a more amenable alkylation partner than the THQ 14 due to the likely lower pKa of the amide proton. To assess this, 13 was reacted with NaH and 2-iodopropane in DMF at 80 °C overnight. However, 13 displayed a marked lack of reactivity towards
Graphical Abstract
Figure 1: Tetrahydroquinoline (THQ) and dihydroquinoline (DHQ) scaffolds to be synthesised.
Scheme 1: Proposed retrosynthesis scheme to access N-isopropyl-THQ 2.
Scheme 2: Synthesis of THQ 3 by initial N-alkylations, followed by PPA-mediated cyclisation.
Scheme 3: Bromination of 3 and attempted halogen exchange of the intermediate 7.
Scheme 4: Synthesis of THQ 10, by initial aza-Michael addition, followed by formation of the tertiary alcohol ...
Scheme 5: Synthesis of THQ 14 by initial acylation, cyclisation with H2SO4 and reduction with borane·dimethyl...
Scheme 6: N-Alkylation of 13 and 14.
Scheme 7: Facile route for the synthesis of 20a.
Scheme 8: Synthesis of THQ 21 and DHQ 22 using borane·dimethyl sulphide complex or DIBAL, respectively.
Figure 2: Simulated structure of 22 indicates a flattened quinoline-like structure. Hartree–Fock calculations...
Scheme 9: Postulated mechanism for the formation of 22 using DIBAL.
Figure 3: Combined, normalised absorption and emission spectra of 28 in chloroform. Absorption spectrum was r...
Scheme 10: Miyaura borylation of 21 and 22 to give crystalline boronic esters 29 and 30.
Figure 4: Comparison of the crystal structures of 29 (left) and 30 (right) as viewed along the plane of the a...
Figure 5: Combined, normalised absorption and emission spectra of 30 in diethyl ether. Absorption spectrum wa...
Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands
- Julia Wappel,
- Roland C. Fischer,
- Luigi Cavallo,
- Christian Slugovc and
- Albert Poater
Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17
- towards the control of polymer functionalization and living or switchable polymerizations. Keywords: acid; activation by acid; metathesis; polymer; quinolin; ruthenium; triggerable; Introduction The modulation of the activity of enzymes by chemical triggers, e.g., by allosteric binding is ubiquitous in
Graphical Abstract
Scheme 1: Synthesis of 1-4; only the isolated and characterized complexes are shown.
Figure 1: Solid state structure of complexes 2a and 2b as retrieved from single crystal X-ray diffraction.
Figure 2: Time/conversion plot for the polymerization of 5 by preinitiators 1–4 in the presence of HCl ([5]:[...
Figure 3: 1H NMR spectrum in the low-field region of the active species for complexes 4 and M32.
Scheme 2: Energetics of 2a and 2b protonation in kcal/mol.
Figure 4: Reaction pathway of the transformation of 2b to HovII (energies in kcal/mol; main distances in Å).
Figure 5: DTA-TGA measurements for polymerizations of DCPD with catalysts 1b and 2b; Reaction conditions: [ca...
