Search for "2H-pyran-2-one" in Full Text gives 18 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178
Graphical Abstract
Scheme 1: Consecutive three-component synthesis of pyrazoles 1 via in situ-formed 1,3-diketones 2 [44].
Scheme 2: Consecutive three-component synthesis of 4-ethoxycarbonylpyrazoles 5 via SmCl3-catalyzed acylation ...
Scheme 3: Consecutive four-component synthesis of 1-(thiazol-2-yl)pyrazole-3-carboxylates 8 [51].
Scheme 4: Three-component synthesis of thiazolylpyrazoles 17 via in situ formation of acetoacetylcoumarins 18 ...
Scheme 5: Consecutive pseudo-four-component and four-component synthesis of pyrazoles 21 from sodium acetylac...
Scheme 6: Consecutive three-component synthesis of 1-substituted pyrazoles 24 from boronic acids, di(Boc)diim...
Scheme 7: Consecutive three-component synthesis of N-arylpyrazoles 25 via in situ formation of aryl-di(Boc)hy...
Scheme 8: Consecutive three-component synthesis of 1,3,4-substituted pyrazoles 27 and 28 from methylhydrazine...
Scheme 9: Consecutive three-component synthesis of 4-allylpyrazoles 32 via oxidative allylation of 1,3-dicarb...
Scheme 10: Pseudo-five-component synthesis of tris(pyrazolyl)methanes 35 [61].
Scheme 11: Pseudo-three-component synthesis of 5-(indol-3-yl)pyrazoles 39 from 1,3,5-triketones 38 [64].
Scheme 12: Three-component synthesis of thiazolylpyrazoles 43 [65].
Scheme 13: Three-component synthesis of triazolo[3,4-b]-1,3,4-thiadiazin-3-yl substituted 5-aminopyrazoles 47 [67]....
Scheme 14: Consecutive three-component synthesis of 5-aminopyrazoles 49 via formation of β-oxothioamides 50 [68].
Scheme 15: Synthesis of 3,4-biarylpyrazoles 52 from aryl halides, α-bromocinnamaldehyde, and tosylhydrazine vi...
Scheme 16: Consecutive three-component synthesis of 3,4-substituted pyrazoles 57 from iodochromones 55 by Suzu...
Scheme 17: Pseudo-four-component synthesis of pyrazolyl-2-pyrazolines 59 by ring opening/ring closing cyclocon...
Scheme 18: Consecutive three-component synthesis of pyrazoles 61 [77].
Scheme 19: Three-component synthesis of pyrazoles 62 from malononitrile, aldehydes, and hydrazines [78-90].
Scheme 20: Four-component synthesis of pyrano[2,3-c]pyrazoles 63 [91].
Scheme 21: Three-component synthesis of persubstituted pyrazoles 65 from aldehydes, β-ketoesters, and hydrazin...
Scheme 22: Three-component synthesis of pyrazol-4-carbodithioates 67 [100].
Scheme 23: Regioselective three-component synthesis of persubstituted pyrazoles 68 catalyzed by ionic liquid [...
Scheme 24: Consecutive three-component synthesis of 4-halopyrazoles 69 and anellated pyrazoles 70 [102].
Scheme 25: Three-component synthesis of 2,2,2-trifluoroethyl pyrazole-5-carboxylates 72 [103].
Scheme 26: Synthesis of pyrazoles 75 in a one-pot process via carbonylative Heck coupling and subsequent cycli...
Scheme 27: Copper-catalyzed three-component synthesis of 1,3-substituted pyrazoles 76 [105].
Scheme 28: Pseudo-three-component synthesis of bis(pyrazolyl)methanes 78 by ring opening-ring closing cyclocon...
Scheme 29: Three-component synthesis of 1,4,5-substituted pyrazoles 80 [107].
Scheme 30: Consecutive three-component synthesis of 3,5-bis(fluoroalkyl)pyrazoles 83 [111].
Scheme 31: Consecutive three-component synthesis of difluoromethanesulfonyl-functionalized pyrazole 88 [114].
Scheme 32: Consecutive three-component synthesis of perfluoroalkyl-substituted fluoropyrazoles 91 [115].
Scheme 33: Regioselective consecutive three-component synthesis of 1,3,5-substituted pyrazoles 93 [116].
Scheme 34: Three-component synthesis of pyrazoles 96 mediated by trimethyl phosphite [117].
Scheme 35: One-pot synthesis of pyrazoles 99 via Liebeskind–Srogl cross-coupling/cyclocondensation [118].
Scheme 36: Synthesis of 1,3,5-substituted pyrazoles 101 via domino condensation/Suzuki–Miyaura cross-coupling ...
Scheme 37: Consecutive three-component synthesis of 1,3,5-trisubstituted pyrazoles 102 and 103 by Sonogashira ...
Scheme 38: Polymer analogous consecutive three-component synthesis of pyrazole-based polymers 107 [132].
Scheme 39: Synthesis of 1,3,5-substituted pyrazoles 108 by sequentially Pd-catalyzed Kumada–Sonogashira cycloc...
Scheme 40: Consecutive four-step one-pot synthesis of 1,3,4,5-substituted pyrazoles 110 [137].
Scheme 41: Four-component synthesis of pyrazoles 113, 115, and 117 via Sonogashira coupling and subsequent Suz...
Scheme 42: Consecutive four- or five-component synthesis for the preparation of 4-pyrazoly-1,2,3-triazoles 119...
Scheme 43: Four-component synthesis of pyrazoles 121 via alkynone formation by carbonylative Pd-catalyzed coup...
Scheme 44: Preparation of 3-azulenyl pyrazoles 124 by glyoxylation, decarbonylative Sonogashira coupling, and ...
Scheme 45: Four-component synthesis of a 3-indoloylpyrazole 128 [147].
Scheme 46: Two-step synthesis of 5-acylpyrazoles 132 via glyoxylation-Stephen–Castro sequence and subsequent c...
Scheme 47: Copper on iron mediated consecutive three-component synthesis of 3,5-substituted pyrazoles 136 [150].
Scheme 48: Consecutive three-component synthesis of 3-substituted pyrazoles 141 by Sonogashira coupling and su...
Scheme 49: Consecutive three-component synthesis of pyrazoles 143 initiated by Cu(I)-catalyzed carboxylation o...
Scheme 50: Consecutive three-component synthesis of benzamide-substituted pyrazoles 146 starting from N-phthal...
Scheme 51: Consecutive three-component synthesis of 1,3,5-substituted pyrazoles 148 [156].
Scheme 52: Three-component synthesis of 4-ninhydrin-substituted pyrazoles 151 [158].
Scheme 53: Consecutive four-component synthesis of 4-(oxoindol)-1-phenylpyrazole-3-carboxylates 155 [159].
Scheme 54: Three-component synthesis of pyrazoles 160 [160].
Scheme 55: Consecutive three-component synthesis of pyrazoles 165 [162].
Scheme 56: Consecutive three-component synthesis of 3,5-disubstituted and 3-substituted pyrazoles 168 and 169 ...
Scheme 57: Three-component synthesis of 3,4,5-substituted pyrazoles 171 via 1,3-dipolar cycloaddition of vinyl...
Scheme 58: Three-component synthesis of pyrazoles 173 and 174 from aldehydes, tosylhydrazine, and vinylidene c...
Scheme 59: Three-component synthesis of pyrazoles 175 from glyoxyl hydrates, tosylhydrazine, and electron-defi...
Scheme 60: Pseudo-four-component synthesis of pyrazoles 177 from glyoxyl hydrates, tosylhydrazine, and aldehyd...
Scheme 61: Consecutive three-component synthesis of pyrazoles 179 via Knoevenagel-cycloaddition sequence [179].
Scheme 62: Three-component synthesis of 5-dimethylphosphonate substituted pyrazoles 182 from aldehydes, the Be...
Scheme 63: Consecutive three-component synthesis of 5-(dimethyl phosphonate)-substituted pyrazoles 185 from al...
Scheme 64: Three-component synthesis of 5-(dimethyl phosphonate)-substituted pyrazoles 187 from aldehydes, the...
Scheme 65: Three-component synthesis of 5-diethylphosphonate/5-phenylsulfonyl substituted pyrazoles 189 from a...
Scheme 66: Pseudo-three-component synthesis of 3-(dimethyl phosphonate)-substituted pyrazoles 190 [185].
Scheme 67: Three-component synthesis of 3-trifluoromethylpyrazoles 193 [186].
Scheme 68: Consecutive three-component synthesis of 5-stannyl-substituted 4-fluoropyrazole 197 [191,192].
Scheme 69: Pseudo-three-component synthesis of 3,5-diacyl-4-arylpyrazoles 199 [195].
Scheme 70: Three-component synthesis of pyrazoles 204 via nitrilimines [196].
Scheme 71: Three-component synthesis of 1,3,5-substituted pyrazoles 206 via formation of nitrilimines and sali...
Scheme 72: Pseudo four-component synthesis of pyrazoles 209 from acetylene dicarboxylates 147, hydrazonyl chlo...
Scheme 73: Consecutive three-component synthesis of pyrazoles 213 via syndnones 214 [200].
Scheme 74: Consecutive three-component synthesis of pyrazoles 216 via in situ-formed diazomethinimines 217 [201].
Scheme 75: Consecutive three-component synthesis of 3-methylthiopyrazoles 219 from aldehydes, hydrazine, and 1...
Scheme 76: Three-component synthesis of 1,3,5-substituted pyrazoles 220 from aldehydes, hydrazines, and termin...
Scheme 77: Three-component synthesis of 1,3,4,5-substituted pyrazoles 222 from aldehydes, hydrazines, and DMAD ...
Scheme 78: Pseudo three-component synthesis of pyrazoles 224 from sulfonyl hydrazone and benzyl acrylate under...
Scheme 79: Titanium-catalyzed consecutive four-component synthesis of pyrazoles 225 via enamino imines 226 [211]. a...
Scheme 80: Titanium-catalyzed three-component synthesis of pyrazoles 227 via enhydrazino imine complex interme...
Scheme 81: Pseudo-three-component synthesis of pyrazoles 229 via Glaser coupling of terminal alkynes and photo...
Scheme 82: Copper(II)acetate-mediated three-component synthesis of pyrazoles 232 [216].
Scheme 83: Copper-catalyzed three-component synthesis of 1,3,4-substituted pyrazole 234 from oxime acetates, a...
Scheme 84: Three-component synthesis of 3-trifluoroethylpyrazoles 239 [218].
Scheme 85: Pseudo-three-component synthesis of 1,4-bisulfonyl-substituted pyrazoles 242 [219].
Scheme 86: Three-component synthesis of 4-hydroxypyrazole 246 [221].
Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168
Graphical Abstract
Figure 1: Selected imidazole-based bioactive molecules.
Scheme 1: Formation of ethyl 2-cyano-2-(1,3-dihydro-2H-imidazole-2-ylidene)acetate derivatives via [3 + 2] cy...
Scheme 2: C–H/C–Li coupling reaction of 2H-imidazole 1-oxides with pentafluorophenyllithium.
Scheme 3: Transition-metal-free coupling reaction of 2H-imidazole 1-oxides with polyphenols. Reaction conditi...
Scheme 4: Halogenation reaction of 2-unsubstituted imidazole N-oxides using tosyl halogenides.
Scheme 5: Solvent-free chlorination reaction of imidazole N-oxides.
Scheme 6: Multicomponent reaction of imidazole N-oxides 28 with Meldrum’s acid (26) and aldehydes.
Scheme 7: Multicomponent reaction of imidazole N-oxides with CH-acids and aldehydes. Reaction conditions: aTh...
Scheme 8: Three-component condensation reaction of imidazole N-oxides, arylglyoxals, and CH-acids 38 (dimedon...
Scheme 9: Synthesis of imidazole-2-thiones containing cyclohexyl-substituents at 3-position.
Scheme 10: Preparation of optically active derivatives of 3-butoxyimidazole-2-thione.
Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143
Graphical Abstract
Figure 1: Structures of leustroducsins and phoslactomycins.
Figure 2: Synthetic strategy for the leustroducins and phoslactomycins.
Figure 3: strategy for the synthesis of central fragment 4: nitroso Diels–Alder reaction.
Scheme 1: A highly regio-and stereoselective nitroso Diels–Alder cycloaddition between Wightman’s reagent 6 a...
Scheme 2: Hydrolysis of enol phosphate in the unprotected cycloadduct.
Scheme 3: Attempts for hydrolysis of the enol phosphate under basic conditions.
Scheme 4: Cleavage of enol phosphate with Red-Al.
Scheme 5: Synthesis of the protected central fragment 11b.
Scheme 6: Synthesis and derivatization of the lactone fragment.
Scheme 7: Coupling reaction between alkyne 19 and ketone 11b.
Scheme 8: Coupling reaction between vinyl iodide 20 and ketone 11b.
Scheme 9: Oxidation of the acetal to the lactone.
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.
Beilstein J. Org. Chem. 2019, 15, 2840–2846, doi:10.3762/bjoc.15.277
Graphical Abstract
Scheme 1: General synthetic pathway to 1.
Scheme 2: Synthesis of acetamides 2.
Scheme 3: Possible reaction pathways for the formation of enaminone 7.
Scheme 4: Possible reaction pathways for the formation of pyrrolo[3,4-b]pyridin-5-one derivatives 1.
Figure 1: View of the structure of 1e in the crystal (CCDC: 1921613). Thermal ellipsoids indicate 50% probabi...
Scheme 5: Tautomeric equilibrium of pyrrolo[3,4-b]pyridin-5-one derivatives 1 in solution.
Beilstein J. Org. Chem. 2018, 14, 2974–2990, doi:10.3762/bjoc.14.277
Graphical Abstract
Figure 1: Structures of fungal volatiles. Trichodiene (1), aristolochene (2), (R)-oct-1-en-3-ol (3), 3,4-dime...
Figure 2: Total ion chromatogram of a CLSA headspace extract from Hypoxylon griseobrunneum MUCL 53754. Peak n...
Figure 3: Volatiles from Hypoxylon griseobrunneum.
Figure 4: EI mass spectra of A) 2,4,5-trimethylanisole (24), B) the coeluting mixture of 3,4-dimethylanisole (...
Scheme 1: Synthesis of trimethylanisoles 24 and 24d.
Scheme 2: Hypothetical biosynthesis of 24. ACP: acyl carrier protein, AT: acyl transferase, KR: ketoreductase...
Figure 5: Biosynthesis of 24. Feeding of (methyl-2H3)methionine resulted in the incorporation of labelling in...
Scheme 3: Hypothetical biosynthesis of 25 and 26.
Figure 6: Total ion chromatogram of a CLSA headspace extract from Hypoxylon macrocarpum STMA 130423. Peak num...
Figure 7: Volatiles from Hypoxylon macrocarpum.
Figure 8: EI mass spectra of A) 3,4-dimethoxybenzaldehyde (42), B) 3,4,5-trimethoxytoluene (44), and C) 2,4,5...
Scheme 4: Synthesis of 2,3,4-trimethoxytoluene (44a).
Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62
Graphical Abstract
Figure 1: Structures of the widespread fungal volatiles oct-1-en-3-ol (1) and 6-pentyl-2H-pyran-2-one (2), th...
Figure 2: Total-ion chromatogram of the bouquet from Hypoxylon invadens MUCL 54175 obtained by the CLSA heads...
Figure 3: Identified volatile organic compounds from Hypoxylon invadens MUCL 54175.
Figure 4: Mass spectra of volatiles from Hypoxylon invadens MUCL 54175. Mass spectra of A) 2,5-dimethylphenol...
Scheme 1: Proposed common biosynthetic pathway to volatile aromatic compounds from Hypoxylon invadens.
Scheme 2: Synthesis of 5-hydroxy-2-methyl-4H-chromen-4-one (19).
Beilstein J. Org. Chem. 2018, 14, 547–552, doi:10.3762/bjoc.14.41
Graphical Abstract
Scheme 1: The Corey–Winter reaction in general.
Scheme 2: Proposed route for the synthesis of metabolites isolated from Trichoderma and Penicillium species f...
Scheme 3: Preparation of thiocarbonate precursor 6 from pyrone dioxolane 7.
Figure 1: Cyclic voltammetry of thiocarbonates 4 (left) and 6 (right); c = 1 × 10−3 M, N2 bubbling 5 min, WE ...
Scheme 4: Putative reaction mechanism of the electrochemical Corey–Winter reaction.
Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15
Graphical Abstract
Figure 1: Selected examples of drugs with fused pyrazole rings.
Figure 2: Typical structures of some fused pyrazoloazines from 5-aminopyrazoles.
Scheme 1: Regiospecific synthesis of 4 and 6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridines.
Scheme 2: Synthesis of pyrazolo[3,4-b]pyridine-6-carboxylates.
Scheme 3: Synthesis of 1,4,6-triaryl-1H-pyrazolo[3,4-b]pyridines with ionic liquid .
Scheme 4: Synthesis of coumarin-based isomeric tetracyclic pyrazolo[3,4-b]pyridines.
Scheme 5: Synthesis of 6-substituted pyrazolo[3,4-b]pyridines under Heck conditions.
Scheme 6: Microwave-assisted palladium-catalyzed synthesis of pyrazolo[3,4-b]pyridines.
Scheme 7: Acid-catalyzed synthesis of pyrazolo[3,4-b]pyridines via enaminones.
Scheme 8: Synthesis of pyrazolo[3,4-b]pyridines via aza-Diels–Alder reaction.
Scheme 9: Synthesis of macrocyclane fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 10: Three-component synthesis of 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine derivatives.
Scheme 11: Ultrasonicated synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones.
Scheme 12: Synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine] derivatives under conventional heating co...
Scheme 13: Nanoparticle-catalyzed synthesis of pyrazolo[3,4-b]pyridine-spiroindolinones.
Scheme 14: Microwave-assisted multicomponent synthesis of spiropyrazolo[3,4-b]pyridines.
Scheme 15: Unexpected synthesis of naphthoic acid-substituted pyrazolo[3,4-b]pyridines.
Scheme 16: Multicomponent synthesis of variously substituted pyrazolo[3,4-b]pyridine derivatives.
Scheme 17: Three-component synthesis of 4,7-dihydropyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]pyridines.
Scheme 18: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanediones.
Scheme 19: Ultrasound-mediated three-component synthesis of pyrazolo[3,4-b]pyridines.
Scheme 20: Multicomponent synthesis of 4-aryl-3-methyl-1-phenyl-4,6,8,9-tetrahydropyrazolo [3,4-b]thiopyrano[4...
Scheme 21: Synthesis of 2,3-dihydrochromeno[4,3-d]pyrazolo[3,4-b]pyridine-1,6-diones.
Scheme 22: FeCl3-catalyzed synthesis of o-hydroxyphenylpyrazolo[3,4-b]pyridine derivatives.
Scheme 23: Ionic liquid-mediated synthesis of pyrazolo[3,4-b]pyridines.
Scheme 24: Microwave-assisted synthesis of pyrazolo[3,4-b]pyridines.
Scheme 25: Multicomponent synthesis of pyrazolo[3,4-b]pyridine-5-carbonitriles.
Scheme 26: Unusual domino synthesis of 4,7-dihydropyrazolo[3,4-b]pyridine-5-nitriles.
Scheme 27: Synthesis of 4,5,6,7-tetrahydro-4H-pyrazolo[3,4-b]pyridines under conventional heating and ultrasou...
Scheme 28: L-Proline-catalyzed synthesis of of pyrazolo[3,4-b]pyridine.
Scheme 29: Microwave-assisted synthesis of 5-aminoarylpyrazolo[3,4-b]pyridines.
Scheme 30: Microwave-assisted multi-component synthesis of pyrazolo[3,4-e]indolizines.
Scheme 31: Synthesis of fluoropropynyl and fluoroalkyl substituted pyrazolo[1,5-a]pyrimidine.
Scheme 32: Acid-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine derivatives.
Scheme 33: Chemoselective and regiospecific synthesis of 2-(3-methylpyrazol-1’-yl)-5-methylpyrazolo[1,5-a]pyri...
Scheme 34: Regioselective synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 35: Microwave-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidine carboxylates.
Scheme 36: Microwave and ultrasound-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 37: Base-catalyzed unprecedented synthesis of pyrazolo[1,5-a]pyrimidines via C–C bond cleavage.
Scheme 38: Synthesis of aminobenzothiazole/piperazine linked pyrazolo[1,5-a]pyrimidines.
Scheme 39: Synthesis of aminoalkylpyrazolo[1,5-a]pyrimidine-7-amines.
Scheme 40: Synthesis of pyrazolo[1,5-a]pyrimidines from condensation of 5-aminopyrazole 126 and ethyl acetoace...
Scheme 41: Synthesis of 7-aminopyrazolo[1,5-a]pyrimidines.
Scheme 42: Unexpected synthesis of 7-aminopyrazolo[1,5-a]pyrimidines under solvent free and solvent-mediated c...
Scheme 43: Synthesis of N-(4-aminophenyl)-7-aryloxypyrazolo[1,5-a]pyrimidin-5-amines.
Scheme 44: Base-catalyzed synthesis of 5,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 45: Synthesis of 6,7-dihydropyrazolo[1,5-a]pyrimidines in PEG-400.
Scheme 46: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine-3-carboxamides.
Scheme 47: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine derivatives under conventional heating and micro...
Scheme 48: Synthesis of N-aroylpyrazolo[1,5-a]pyrimidine-5-amines.
Scheme 49: Regioselective synthesis of ethyl pyrazolo[1,5-a]pyrimidine-7-carboxylate.
Scheme 50: Sodium methoxide-catalyzed synthesis of 3-cyano-6,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 51: Synthesis of various pyrazolo[3,4-d]pyrimidine derivatives.
Scheme 52: Synthesis of hydrazinopyrazolo[3,4-d]pyrimidine derivatives.
Scheme 53: Synthesis of N-arylidinepyrazolo[3,4-d]pyrimidin-5-amines.
Scheme 54: Synthesis of pyrazolo[3,4-d]pyrimidinyl-4-amines.
Scheme 55: Iodine-catalyzed synthesis of pyrazolo[3,4-d]pyrimidinones.
Scheme 56: Synthesis of ethyl 6-amino-2H-pyrazolo[3,4-d]pyrimidine-4-carboxylate.
Scheme 57: Synthesis of 4-substituted-(3,6-dihydropyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidines.
Scheme 58: Synthesis of 1-(2,4-dichlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl carboxamides.
Scheme 59: Synthesis of 5-(1,3,4-thidiazol-2-yl)pyrazolo[3,4-d]pyrimidine.
Scheme 60: One pot POCl3-catalyzed synthesis of 1-arylpyrazolo[3,4-d]pyrimidin-4-ones.
Scheme 61: Synthesis of 4-amino-N1,C3-dialkylpyrazolo[3,4-d]pyrimidines under Suzuki conditions.
Scheme 62: Microwave-assisted synthesis of pyrazolo[3,4-b]pyrazines.
Scheme 63: Synthesis and derivatization of pyrazolo[3,4-b]pyrazine-5-carbonitriles.
Scheme 64: Synthesis of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones.
Scheme 65: Synthesis of 2,3-dihydropyrazolo[1,5-a][1,3,5]triazin-4(1H)-one.
Scheme 66: Synthesis of pyrazolo[1,5-a][1,3,5]triazine-8-carboxylic acid ethyl ester.
Scheme 67: Microwave-assisted synthesis of 4,7-dihetarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 68: Alternative synthetic route to 4,7-diheteroarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 69: Synthesis of 4-aryl-2-ethylthio-7-methylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 70: Microwave-assisted synthesis of 4-aminopyrazolo[1,5-a][1,3,5]triazine.
Scheme 71: Synthesis of pyrazolo[3,4-d][1,2,3]triazines from pyrazol-5-yl diazonium salts.
Scheme 72: Synthesis of 2,5-dihydropyrazolo[3,4-e][1,2,4]triazines.
Scheme 73: Synthesis of pyrazolo[5,1-c][1,2,4]triazines via diazopyrazolylenaminones.
Scheme 74: Synthesis of pyrazolo[5,1-c][1,2,4]triazines in presence of sodium acetate.
Scheme 75: Synthesis of various 7-diazopyrazolo[5,1-c][1,2,4]triazine derivatives.
Scheme 76: One pot synthesis of pyrazolo[5,1-c][1,2,4]triazines.
Scheme 77: Synthesis of 4-amino-3,7,8-trinitropyrazolo-[5,1-c][1,2,4]triazines.
Scheme 78: Synthesis of tricyclic pyrazolo[5,1-c][1,2,4]triazines by azocoupling reaction.
Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9
Graphical Abstract
Scheme 1: A selection of widespread fungal volatiles.
Figure 1: Total ion chromatogram of a representative headspace extract from Daldinia clavata MUCL 47436. Peak...
Scheme 2: Identified volatiles from Daldinia clavata MUCL 47436.
Figure 2: Mass spectra of volatiles from D. clavata that were identified by synthesis.
Scheme 3: Synthesis of manicone (10).
Scheme 4: Synthesis of a racemic mixture of all four diastereomers of 11.
Figure 3: Gas chromatographic analysis of 11 on a homochiral stationary phase. a) Synthetic mixture of all ei...
Scheme 5: Enantioselective synthesis of (4R,5S,6S)-11c and (4S,5R,6S)-11d.
Scheme 6: Epimerisations of (4R,5S,6S)-11c and (4S,5R,6S)-11d under basic conditions.
Figure 4: Gas chromatographic analysis of 11 on a homochiral stationary phase. a) Synthetic mixture of all ei...
Scheme 7: Proposed biosynthesis for (4R,5R,6S)-11a.
Figure 5: Mass spectra of a) 6-methyl-5,6-dihydro-2H-pyran-2-one (9), b) 6-propyl-5,6-dihydro-2H-pyran-2-one,...
Scheme 8: Synthesis of 6-methyl-5,6-dihydro-2H-pyran-2-one (9) and 6-nonyl-2H-pyran-2-one (17).
Beilstein J. Org. Chem. 2016, 12, 1608–1615, doi:10.3762/bjoc.12.157
Graphical Abstract
Scheme 1: The synthesis of syn-β-lactams using a reductive Mannich-type reaction.
Scheme 2: Previous results using β-substituted α,β-unsaturated esters.
Scheme 3: A new synthetic route for ezetimibe.
Figure 1: Plausible mechanism for the Rh-catalyzed reductive Mannich-type reaction.
Scheme 4: Effect of the Lewis acid addition.
Figure 2: Reaction of 2k and 1A and the configuration of Int A.
Scheme 5: Transition-state model without Lewis acid.
Scheme 6: Transition-state model with Lewis acid.
Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148
Graphical Abstract
Scheme 1: Schematic description of the cyclisation reaction catalysed by TE domains. In most cases, the nucle...
Scheme 2: Mechanisms for the formation of oxygen heterocycles. The degree of substitution can differ from tha...
Scheme 3: Pyran-ring formation in pederin (24) biosynthesis. Incubation of recombinant PedPS7 with substrate ...
Scheme 4: The domain AmbDH3 from ambruticin biosynthesis catalyses the dehydration of 25 and subsequent cycli...
Scheme 5: SalBIII catalyses dehydration of 29 and subsequent cyclisation to tetrahydropyran 30 [18].
Figure 1: All pyranonaphtoquinones contain either the naphtha[2,3-c]pyran-5,10-dione (32) or the regioisomeri...
Scheme 6: Pyran-ring formation in actinorhodin (34) biosynthesis. DNPA: 4-dihydro-9-hydroxy-1-methyl-10-oxo-3H...
Scheme 7: Pyran formation in granaticin (36) biosynthesis. DNPA: 4-dihydro-9-hydroxy-1-methyl-10-oxo-3H-napht...
Scheme 8: Pyran formation in alnumycin (37) biosynthesis. Adapted from [21].
Scheme 9: Biosynthesis of pseudomonic acid A (61). The pyran ring is initially formed in 57 after dehydrogena...
Scheme 10: Epoxidation–cyclisation leads to the formation of the tetrahydropyran ring in the western part of t...
Scheme 11: a) Nonactin (70) is formed from heterodimers of (−)(+)-dimeric nonactic acid and (+)(−)-dimeric non...
Figure 2: Pamamycins (73) are macrodiolide antibiotics containing three tetrahydrofuran moieties, which are a...
Scheme 12: A PS domain homolog in oocydin A (76) biosynthesis is proposed to catalyse furan formation via an o...
Scheme 13: Mechanism of oxidation–furan cyclisation by AurH, which converts (+)-deoxyaureothin (77) into (+)-a...
Scheme 14: Leupyrrin A2 (80) and the proposed biosynthesis of its furylidene moiety [69,70].
Scheme 15: Asperfuranone (93) biosynthesis, adapted from [75].
Figure 3: The four major aflatoxins produced by Aspergilli are the types B1, B2, G1 and G2 (94–97). In the di...
Scheme 16: Overview on aflatoxin B1 (94) biosynthesis. HOMST = 11-hydroxy-O-methylsterigmatocystin [78,79,82-106].
Scheme 17: A zipper mechanism leads to the formation of oxygen heterocycles in monensin biosynthesis [109-111].
Scheme 18: Formation of the 2,6-dioxabicyclo[3.2.1]octane (DBO) ring system in aurovertin B (118) biosynthesis ...
Figure 4: Structures of the epoxide-containing polyketides epothilone A (119) and oleandomycin (120) [123-125].
Scheme 19: Structures of phoslactomycin B (121) (a) and jerangolid A (122) (b). The heterocycle-forming steps ...
Scheme 20: a) Structures of rhizoxin (130) and cycloheximide (131). Model for the formation of δ-lactones (b) ...
Scheme 21: EncM catalyses a dual oxidation sequence and following processing of the highly reactive intermedia...
Figure 5: Mesomeric structures of tetronates [138,139].
Figure 6: Structures of tetronates for which gene clusters have been sequenced. The tetronate moiety is shown...
Scheme 22: Conserved steps for formation and processing in several 3-acyl-tetronate biosynthetic pathways were...
Scheme 23: In versipelostatin A (153) biosynthesis, VstJ is a candidate enzyme for catalysing the [4 + 2] cycl...
Scheme 24: a) Structures of some thiotetronate antibiotics. b) Biosynthesis of thiolactomycin (165) as propose...
Scheme 25: Aureusidine synthase (AS) catalyses phenolic oxidation and conjugate addition of chalcones leading ...
Scheme 26: a) Oxidative cyclisation is a key step in the biosynthesis of spirobenzofuranes 189, 192 and 193. b...
Scheme 27: A bicyclisation mechanism forms a β-lactone and a pyrrolidinone and removes the precursor from the ...
Scheme 28: Spontaneous cyclisation leads to off-loading of ebelactone A (201) from the PKS machinery [163].
Scheme 29: Mechanisms for the formation of nitrogen heterocycles.
Scheme 30: Biosynthesis of highly substituted α-pyridinones. a) Feeding experiments confirmed the polyketide o...
Scheme 31: Acridone synthase (ACS) catalyses the formation of 1,3-dihydroxy-N-methylacridone (224) by condensa...
Scheme 32: A Dieckmann condensation leads to the formation of a 3-acyl-4-hydroxypyridin-2-one 227 and removes ...
Scheme 33: a) Biosynthesis of the pyridinone tenellin (234). b) A radical mechanism was proposed for the ring-...
Scheme 34: a) Oxazole-containing PKS–NRPS-derived natural products oxazolomycin (244) and conglobatin (245). b...
Scheme 35: Structure of tetramic acids 251 (a) and major tautomers of 3-acyltetramic acids 252a–d (b). Adapted...
Scheme 36: Equisetin biosynthesis. R*: terminal reductive domain. Adapted from [202].
Scheme 37: a) Polyketides for which a similar biosynthetic logic was suggested. b) Pseurotin A (256) biosynthe...
Figure 7: Representative examples of PTMs with varying ring sizes and oxidation patterns [205,206].
Scheme 38: Ikarugamycin biosynthesis. Adapted from [209-211].
Scheme 39: Tetramate formation in pyrroindomycin aglycone (279) biosynthesis [213-215].
Scheme 40: Dieckmann cyclases catalyse tetramate or 2-pyridone formation in the biosynthesis of, for example, ...
Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56
Graphical Abstract
Figure 1: Selected monocyclic and monobenzo α-pyrone structures.
Figure 2: The basic core structure of dibenzo-α-pyrones.
Figure 3: Selected dibenzo-α-pyrones.
Figure 4: Structure of ellagic acid and of the urolithins, the latter metabolized from ellagic acid by intest...
Figure 5: Structure of murayalactone, the only dibenzo-α-pyrone described from bacteria.
Figure 6: Structures of the 6-pentyl-2-pyrone (29) and of trichopyrone (30). Only 29 showed antifungal activi...
Figure 7: Selected monocyclic α-pyrones.
Figure 8: Structures of the gibepyrones A–F.
Figure 9: Structures of the phomenins A and B.
Figure 10: Structures of monocyclic α-pyrones showing pheromone (47) and antitumor activity (48), respectively....
Figure 11: Structures of 6-alkyl (alkoxy or alkylthio)-4-aryl-3-(4-methanesulfonylphenyl)pyrones.
Figure 12: Structures of kavalactones.
Figure 13: Strutures of germicins.
Figure 14: Structures of the pseudopyronines.
Figure 15: The structures of the monobenzo-α-pyrone anticoagulant drugs warfarin and phenprocoumon.
Figure 16: Structures of selected monobenzo-α-pyrones.
Figure 17: Hypothetical pathway of 29 generation from linoleic acid [34].
Figure 18: Proposed biosynthetic pathway of alternariol (modified from [77]). Malonyl-CoA building blocks are appl...
Figure 19: Structures of phenylnannolones and of enterocin, both biosynthesized via polyketide synthase system...
Figure 20: Pyrone ring formation. Examples for the three types of PKS systems are shown in A–C. In D the mecha...
Figure 21: Structures of csypyrones.
Figure 22: Schematic drawing of the T-shaped catalytic cavities of the related enzymes CorB and MxnB. The two ...
Figure 23: Stereo representation of the CorB binding situation (modified from [89]). The substrate mimic (dark vio...
Figure 24: Proposed mechanism for the CsyB enzymatic reaction. A) Coupling reaction of the β-keto fatty acyl i...
Figure 25: Proposed biosynthesis of photopyrone D (37) by the enzyme PpyS from P. luminescens (modified from [63])...
Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179
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 ...
Beilstein J. Org. Chem. 2014, 10, 890–896, doi:10.3762/bjoc.10.86
Graphical Abstract
Scheme 1: PET-catalyzed addition of N,N-dimethylaniline (1) to furan-2(5H)-one 2 [38] and of N-methyl-N-((trimeth...
Scheme 2: Ir-catalyzed formation of tricyclic product 10 by a domino radical addition reaction to α,β-unsatur...
Scheme 3: Ir-catalyzed addition reactions of N-methyl-N-((trimethylsilyl)methyl)aniline (5) to 5,6-dihydro-2H...
Scheme 4: Ir-catalyzed addition reactions of N-methyl-N-((trimethylsilyl)methyl)aniline (5) to 2-cyclopenteno...
Scheme 5: Ir-catalyzed formation of tricyclic products 19 by a domino radical addition reaction to α,β-unsatu...
Scheme 6: Ir-catalyzed addition reactions of N-methyl-N-((trimethylsilyl)methyl)aniline (5) to α,β-unsaturate...
Scheme 7: Ir-catalyzed addition reactions of N-methyl-N-((trimethylsilyl)methyl)aniline (5) to α,β-unsaturate...
Scheme 8: Cyclization of putative radical A to intermediate B competes with reduction of A to form addition p...
Beilstein J. Org. Chem. 2013, 9, 809–817, doi:10.3762/bjoc.9.92
Graphical Abstract
Scheme 1: Syntheses of 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles 3.
Figure 1: ORTEP view with atom numbering scheme of compound 5 with displacement ellipsoids at the 30% probabi...
Scheme 2: A plausible mechanism for the formation of 1-aryl-3-methylthio-5H-dibenzo[d,f][1,3]diazepin-6(7H)-o...
Scheme 3: Synthesis of 3-alkenylindolin-2-ones.
Figure 2: ORTEP view with atom numbering scheme of compound 8yc with displacement ellipsoids at the 30% proba...
Scheme 4: Synthesis of 1-aryl-3-sec-amino-5H-dibenzo[d,f][1,3]diazepin-6(7H)-ones 10.
Figure 3: Centrosymmetric dimer of 8yc bound by a pair of weak C−H…π intermolecular interactions (symm. op. 2...
Figure 4: Supramolecular chain of 8yc bound by weak C−H…O intermolecular interactions (symm. op. x,1 + y, z).
Figure 5: Supramolecular chain of 8yc bound by weak C−H…O and Ar-H…π intermolecular interactions (symm. op. 2...
Beilstein J. Org. Chem. 2009, 5, No. 64, doi:10.3762/bjoc.5.64
Graphical Abstract
Figure 1: Polycyclic azaheteroaromatics (A) and pyrano[4,3-c]pyrazol-4(1H)-ones (B).
Scheme 1: Pd/C-mediated synthesis of 6-substituted pyrano[4,3-c]pyrazol-4(1H)-ones 3.
Scheme 2: Preparation of 5-iodo-1-methyl-1H-pyrazole-4-carboxylic acid (1).
Scheme 3: Mechanism of ring closure of intermediate alkyne Z.
Beilstein J. Org. Chem. 2009, 5, No. 14, doi:10.3762/bjoc.5.14
Graphical Abstract
Figure 1: Some natural products containing styryl lactones.
Figure 2: Retrosynthetic approach.
Scheme 1: Synthesis of chiral propargyl secondary hydroxyl group.
Scheme 2: Determination of the stereochemistry of the 1,3-anti diols.
Scheme 3: Synthesis of cryptocaryalactone by RCM.