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Search for "Strecker degradation" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
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
- introduces primary amines for 1,3-dipolar cycloaddition which is less explored due to the probability of competitive Strecker degradation over decarboxylation of azomethine ylides. The protocol reveals the efficiency of MW assisted reaction with reduced reaction time from 18 h to 12 min and enhanced the
- ylide formation over the expected Strecker degradation. The azomethine ylide trapped by 3-alkenylindole undergoes 1,3-dipolar cycloaddition and led to the cycloadducts 44. 4 Pyrans Pyran is a six-membered heterocyclic, non-aromatic ring, consisting of five carbon atoms and one oxygen atom with two
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.
Biomimetic synthesis and HPLC–ECD analysis of the isomers of dracocephins A and B
- Viktor Ilkei,
- András Spaits,
- Anita Prechl,
- Áron Szigetvári,
- Zoltán Béni,
- Miklós Dékány,
- Csaba Szántay Jr,
- Judit Müller,
- Árpád Könczöl,
- Ádám Szappanos,
- Attila Mándi,
- Sándor Antus,
- Ana Martins,
- Attila Hunyadi,
- György Tibor Balogh,
- György Kalaus (†),
- Hedvig Bölcskei,
- László Hazai and
- Tibor Kurtán
Beilstein J. Org. Chem. 2016, 12, 2523–2534, doi:10.3762/bjoc.12.247
- –pyrrolidone conjugates is proposed by Leete [3] and Tanaka et al. [4] to proceed via an acylaminocarbinol intermediate, which presumably arises through the Strecker-degradation of the corresponding amino acids, which is L-glutamine (4) in the case of dracocephins A and B as shown in Scheme 1. The spontaneous
Graphical Abstract
Figure 1: Structures of (±)-naringenin, (±)-dracocephins A1–A4 and B1–B4 with the indication of the absolute ...
Scheme 1: Proposed biosynthetic route to dracocephins A and B.
Scheme 2: Synthesis of (±)-5-ethoxypyrrolidine-2-one ((±)-9).
Scheme 3: Synthesis of (±)-dracocephins A and B (±)-2a–d and (±)-3a–d and the elution order of stereoisomers ...
Figure 2: a) Chiral HPLC–UV and HPLC–ECD traces of dracocephins A (2a–d) using Chiralpak IC column with the e...
Figure 3: Structure and population of the low-energy CAM-B3LYP/TZVP PCM/CHCl3 conformers (>2%) of (R)-1.
Figure 4: Experimental HPLC–ECD spectrum of (R)-naringenin ((R)-1) compared with the Boltzmann-weighted ECD s...
Figure 5: Structure and population of the low-energy CAM-B3LYP/TZVP PCM/MeCN conformers (>2%) of (2R,5’’R)-2d....
Figure 6: Structure and population of the low-energy CAM-B3LYP/TZVP PCM/MeCN conformers (>2%) of (2R,5’’S)-2a....
Figure 7: Experimental HPLC-ECD spectra of (2R,5’’S)-2a (second eluted stereoisomer) and (2R,5’’R)-2d (fourth...
Figure 8: Experimental HPLC–ECD spectra of (2R,5’’S)-2a and (2R,5’’R)-2d compared with the Boltzmann-weighted...
Figure 9: a) Chiral HPLC–UV and HPLC–ECD traces of dracocephins B1–B4 3a–d using a Chiralpak IC column with t...
Figure 10: Structure and population of the low-energy CAM-B3LYP/TZVP PCM/MeCN conformers (>2%) of (2R,5’’R)-3c....
Figure 11: Structure and population of the low-energy CAM-B3LYP/TZVP PCM/MeCN conformers (>2%) of (2R,5’’S)-3b....
Figure 12: Experimental HPLC-ECD spectra of 3b (first eluted stereoisomer) and 3c (third eluted stereoisomer) ...
Figure 13: Experimental HPLC-ECD spectra of 3b and 3c compared with the Boltzmann-weighted ECD spectra compute...
Figure 14: Proposed mechanism for the formation of dracocephins A and B (2a–d and 3a–d) starting from (±)-9.
Strecker degradation of amino acids promoted by a camphor-derived sulfonamide
- M. Fernanda N. N. Carvalho,
- M. João Ferreira,
- Ana S. O. Knittel,
- Maria da Conceição Oliveira,
- João Costa Pessoa,
- Rudolf Herrmann and
- Gabriele Wagner
Beilstein J. Org. Chem. 2016, 12, 732–744, doi:10.3762/bjoc.12.73
- connected by a –N= bridge, and thus has a structural analogy to the colored product Ruhemann´s purple obtained by the ninhydrin reaction with amino acids. A plausible reaction mechanism that involves zwitterions, a Strecker degradation of an intermediate imine and water-catalyzed tautomerizations was
- developed by means of DFT calculations on potential transition states. Keywords: amino acids; camphorsulfonylimine; DFT calculations; NMR characterization; Strecker degradation; Introduction Among the many derivatives of natural camphor, oxoimine 1 (Figure 1) shows an especially versatile chemistry. The C
- observation suggests a reaction similar to the “ninhydrin reaction” which is used in the identification/analysis of amino acids [18]. The central part of this reaction is the Strecker degradation [19] of an intermediate imine. The surprising instability of the otherwise robust amino acids upon the formation
Graphical Abstract
Figure 1: Camphor and some camphor derivatives.
Scheme 1: Formation of 2 from reaction of oxoimine 1 with amino acids (H2NCH(R)COOH: R = H, CH3, CH2Ph, CH2CH...
Figure 2: ESI mass spectrum of 2 (positive ion mode).
Figure 3: 1H NMR spectrum of 2 in CD3CN at T = −20 °C.
Figure 4: 13C NMR spectrum of 2 in CD3CN at T = −20 °C.
Figure 5: Optimized structure of 2 ((S)-3A isomer) with labeling scheme.
Figure 6: NOESY spectrum (detail) showing the cross peak between H3A and H10A (see Supporting Information File 1, Figure S6 for the full s...
Figure 7: Upper row: anion 3 and zwitterion 4 which are stable upon geometry optimization. Middle row: zwitte...
Figure 8: Intramolecular reactions of non-zwitterionic ground state 6g to 11 (top) or 8 (bottom). The activat...
Figure 9: Transition-state geometry and salient bond distances along the IRC path for the reaction of 6g → 11...
Figure 10: Transition-state geometry and salient bond distances along the IRC path for the reaction of 6g → 8....
Figure 11: Potential products 7–11 of the Strecker degradation together with the reaction of compound 10 to gi...
Figure 12: ESI(+) tandem mass spectrum of the intermediate 12 (m/z 229) and proposed fragment ions.
