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1.
Synthetic approaches towards new condensed thienopyridine ring systems including furo[2,3-b]thieno[3,2-e]pyridines, bisthieno[2,3-b:3′,2′-e]pyridines, 5H-chromeno[2,3-b]thieno[3,2-e]pyridines, 5H-benzo(f)chromeno[2,3-b]thieno[3,2-e]pyridines have been achieved by application of intramolecular 4+2 cycloaddition reactions of suitably designed thieno[2,3-e][1,2,4]triazines tethered with alkene or alkyne terminals. 相似文献
2.
Abderrahman El Bouakher Hélène LaborieMina Aadil Ahmed El HakmaouiSaid Lazar Mohamed Akssira Marie-Claude Viaud-Massuard 《Tetrahedron letters》2011,52(39):5077-5080
A convenient synthesis of a series of pyrido[3,2-e][1,4]-diazepine-2,5-diones 8 and pyrido[2,3-e][1,4]diazepine-2,5-diones 9, is reported using the condensation of α-amino acid methyl ester derivatives with 1H-pyrido[3,2-d][1,3]oxazine-2,4-dione and 1H-pyrido[2,3-d][1,3]oxazine-2,4-dione. Compounds 8 and 9 were also synthesized by peptide coupling of α-amino acid methyl ester derivatives with β-amino acids (2 or 3) followed by the cyclisation in tetrahydrofuran with sodium hydride (NaH). 相似文献
3.
A practical synthesis of 2H-pyrimido[4,5-e][1,2,4]triazin-3-ylidenecyanamides has been developed. The key step is the coupling reaction of an aryldiazonium salt with 1-cyano-3-(2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-ylamino)-2-methylisothiourea followed by intramolecular cyclization. A library of 2H-pyrimido[4,5-e][1,2,4]triazin-3-ylidenecyanamides was prepared in two steps from 6-aminouracils using this method. 相似文献
4.
Abderrahman El Bouakher Gildas PriéMina Aadil Said LazarMohamed Akssira Marie-Claude Viaud-Massuard 《Tetrahedron》2012,68(47):9572-9577
A novel methodology has been developed for the efficient synthesis of 1,4-pyridopyrrolodiazepine derivatives. The key reaction is the bromination under mild conditions by NBS of compounds resulting via peptide coupling of l-proline methyl ester with 3-aminopyridine-2-carboxylic acid 1, then intramolecular cyclization in the construction of 2-bromo-6a,7,8,9-tetrahydro-5H-pyrido[3,2-e]pyrrolo[1,2-a][1,4]diazepine-6,11-dione 4. This latter is then engaged in cross-coupling reactions to generate 1,4-pyridopyrrolodiazepines derivatives 5a-m, 6a-i, 7, and 8a-c. This strategy provides an efficient method to access a library of compounds based on privileged substructures that are of great interest in drug discovery. 相似文献
5.
Margarita Suárez Hector Novoa Yamila Verdecia Amaury Alvarez Rolando Pérez Dolores Molero Norbert M. Blaton Nazario Martín 《Tetrahedron》2006,62(7):1365-1371
Unprecedented 2-iminium chloride salts of 5,8-dihydro-2H-pyrido[3,2-e][1,3]thiazines derivatives (8) were easily synthesized in one step from the corresponding o-chloroformyl-1,4-dihydropyridine (2) and thiourea. The structural study has been carried out by X-ray crystallography and theoretical calculations at the B3LYP/6-31G* levels and reveal that the new salts exhibit appropriate structural features to behave as calcium channel modulators. 相似文献
6.
Nazariy T. Pokhodylo 《Tetrahedron》2009,65(13):2678-3577
New heterocyclic azides, ethyl 2-azido-4-R1-5-R2-3-thiophenecarboxylates, were synthesized by diazotization of 2-aminothiophenes and subsequent treatment with sodium azide. The reactions of these heterocyclic azides with β-ketoesters and activated acetonitriles were studied. The derivatives of thieno[3,2-e][1,2,3]triazolo[1,5-a]pyrimidine, a new ring system, were prepared in high yields via an anionic hetero-domino reaction. 相似文献
7.
Alkylation of 1H-6-methyl-3-phenyl-pyrazolo[5,1-c][1,2,4]triazole and 1H-7-ethoxycarbonyl-6-methyl-3-phenyl-pyrazolo[5,1-c][1,2,4]triazole using different alkylating agents leads regioselectively to 1-N-alkylated products. The hydrolysis-decarboxylation of 1,6-dimethyl-7-ethoxycarbonyl-pyrazolo[5,1-c][1,2,4]triazole yields a compound identical with that obtained by the direct methylation of 1H-6-methyl-3-phenyl-pyrazolo[5,1-c][1,2,4]triazole. The 1-N-alkylation is confirmed by NMR spectroscopy and mass spectrometry. 相似文献
8.
An efficient one-pot synthetic method for the highly substituted 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives has been accomplished via a microwave irradiation of MCRs of various aldehydes, 2-aminothiadiazole, and acetoacetate without any catalyst in acetic acid. This approach provides a convenient one pot method for the synthesis of 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives. 相似文献
9.
Ouro-Sama Adetchessi 《Tetrahedron》2005,61(18):4453-4460
2-Substituted-4a-hydroxy-9H-cycloalkyl[1,2-e]oxazolo[3,2-a]pyrimidin-9-ones 2a-c were synthesized by an one-step cyclocondensation from the 5-substituted-2-amino-2-oxazolines 1a-c with ethyl 2-oxocyclohexanecarboxylate in ethanol at room temperature, and easily dehydrated to provide 2-substituted-9H-cycloalkyl[1,2-e]oxazolo[3,2-a]pyrimidin-9-ones 3. In refluxing xylene, the reaction conducted with various ethyl 2-oxocycloalkanecarboxylates led to the two isomeric 2-substituted-8/9H-cycloalkyl[1,2-e]oxazolo[3,2-a]pyrimidin-8/9-ones 3 and 2-substituted-5H-cycloalkyl[1,2-d]oxazolo[3,2-a]pyrimidin-5-ones 4. The structure of some compounds was unambiguously established using X-ray crystallography. According to results from the DSC analysis of compound 2a, formation of the thermodynamically stable pyrimidinones 4 could be related to an intramolecular rearrangement of kinetically controlled pyrimidinones 3. 相似文献
10.
The synthesis of N-cyclohexyl-10-(2-fluorophenyl)-8aH-oxazolo[3,2-a][1,10]phenanthroline and N-(2,6-dimethylphenyl)-10-(2-fluorophenyl)-8aH-oxazolo[3,2-a][1,10]phenanthroline by reaction of 2-fluorobenzaldehyde, phenanthroline and cyclohexyl or 2,6-dimethylphenyl isocyanide is reported. 相似文献
11.
Vegar Stockmann 《Tetrahedron》2008,64(49):11180-11184
Three novel pyrido-fused tris-heterocycles have been prepared based on a Suzuki coupling and subsequent cyclisation approach. Pyrido[4,3-e]pyrrolo[2,3-c]pyridazine (3b, 77%) and pyrido[4,3-e]furano[2,3-c]pyridazine (5b, 76%) were obtained by intramolecular diazocoupling. Successful diazocoupling of furan (5b) is thus reported for the first time by NOBF4 generation of the diazonium intermediate. N-TIPS-pyrido[3,4-b]pyrrolo[3,2-d]pyrrole (TIPS-4b) was synthesised by thermal cyclisation of pyridyl nitrene in considerably higher yield (71%) than previously experienced from similar cyclisations, due to TIPS-activation. 相似文献
12.
A series of novel N-benzylcarboxamide derivatives of bicyclic compounds, 3,4-dihydropyrido[3,2-f][1,4]oxazepin-5(2H)-one and 2,3,4,5-tetrahydro-6H-pyrido[2,3-b][1,5]oxazocin-6-one, were synthesized by cyclization of N-benzyl-2-chloro-N-(2-hydroxyethyl)- [and -(3-hydroxypropyl)-] nicotinamides, respectively. Atropisomerism was observed in 5-[3,5-bis(trifluoromethyl)benzyl]-7-phenyl-2,3,4,5-tetrahydro-6H-pyrido[2,3-b][1,5]oxazocin-6-ones due to steric hindrance of the carboxamide moiety and restriction of its rotation. Cyclization of N-[3,5-bis(trifluoromethyl)benzyl]-2-chloro-N-[(2S)-3-hydroxy-2-methylpropyl]-5-methyl-4-phenylnicotinamide gave (3S)-5-[3,5-bis(trifluoromethyl)benzyl]-3,8-dimethyl-7-phenyl-2,3,4,5-tetrahydro-6H-pyrido[2,3b][1,5]oxazocin-6-one, which exists predominantly in the thermodynamically stable aR-conformer in CDCl3. This compound showed excellent NK1-antagonistic activity with IC50 value (in vitro inhibition of [125I]-Bolton-Hunter-substance P binding in human IM-9 cells) of 0.47 nM, which is ca. 200-fold more potent than that of its enantiomer, indicating that the atropisomer chirality affects NK1-receptor recognition. 相似文献
13.
E. V. Vorob’ev E. S. Kurbatov V. V. Krasnikov V. V. Mezheritskii E. V. Usova 《Russian Chemical Bulletin》2006,55(8):1492-1497
7H-Pyrrolo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines were synthesized by the reactions of 2-ethoxymethyleneamino-1H-pyrrole-3-carbonitriles with acid hydrazides and by the reactions of aminoiminopyrimidines (prepared based on the above-mentioned
carbonitriles) with acid chlorides.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1438–1443, August, 2006. 相似文献
14.
Makhluf J. Haddadin Claudia El-Nachef Yara Chaaban James C. Fettinger 《Tetrahedron letters》2010,51(51):6687-6689
Synthesis of the strained 2H-thieto[3,2-b]quinoline ring system is reported for the first time. Treatment of (Z)-2-benzyliden-2H-thieto[3,2-b]quinoline derivatives of this heterocycle with base, at reflux in ethanol, causes a novel rearrangement to 2-phenylthieno[3,2-b]quinolines. Indeed, the one-pot reaction of 2-aminobenzaldehydes and (Z)-2-benzylidenethietan-3-one in refluxing basic ethanol leads directly to 2-phenylthieno[3,2-b]quinolines in good yields. 相似文献
15.
The thermolysis of (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylic acids in Ac2O led to novel 3-methylene-2,5-dioxo-3H,9bH-oxazolo[2,3-a]isoindoles and chiral (9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindoles were obtained on FVP. Starting from l-cysteine methyl ester (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazines were obtained as single stereoisomers. The thermolysis of (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazine-3-carboxylic acid in Ac2O gave 5-acetyl-2-phenyl-2,3-dihydrothiazole. The structures of methyl (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylate 1a and methyl (2R,4R)-N-chlorocarbonyl-2-(2-hydroxyphenyl)thiazolidine-4-carboxylate 9 were determined by X-ray crystallography. 相似文献
16.
5-Hydroxy uracils or 4-hydroxy[1]benzopyran-2-ones were refluxed with 2-bromobenzyl bromides in acetone in the presence of anhydrous potassium carbonate to afford a number of 5-(2′-bromobenzyloxy) pyrimidine-2,4-dione (80-92%) or 4-(2′-bromobenzyloxy) benzopyran-7-ones (70-82%) respectively. These were then refluxed with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of a catalytic amount of azobisisobutyronitrile (AIBN) for 3-4 h to give 1H,3H,6H [2]benzopyrano[4,3-d]pyrimidine-2,4-diones (75-85%) or 12H-benzopyrano[3,2-c][1]benzopyran-5-ones (70-85%) respectively. 相似文献
17.
An efficient synthesis of 3-amino-6-bromofuro[3,2-b]pyridine-2-carboxamides is described via the formation of 3-amino-6-bromofuro[3,2-b]pyridine-2-carbonitrile. Functionalization of the amino group at position 3 of the heterocycle will be discussed. 相似文献
18.
A series of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidines were prepared via oxidative cyclization of aldehyde N-(1,3-diphenylpyrazolo[3,4-d]pyrimidin-4-yl)hydrazones. Dimroth rearrangement of such a series yielded pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines. 相似文献
19.
Reactions of 3-alkylamino-6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones with cyclohexyl- and cycloheptylamines in the presence of AgPy2MnO4 produce novel cycloalkano[1″,2″:4,5;4″,3″:4′,5′]bis(pyrrolo[2,3-c]pyrimido[5,4-e]pyridazines). Detailed information concerning the scope and mechanism of these transformations is discussed. 相似文献
20.
An expeditious, one-pot, pseudo four-component coupling reaction between 3-hydroxy coumarin, formaldehyde, and amine catalyzed by reusable TiO2 nanopowder in ethanol at room temperature (25–28 °C) under stirring condition to synthesize the chromeno[4,3-e][1,3]oxazine derivatives has been described. A wide range of substrate variation, environmentally benign reaction procedure, easy work-up, chromatography free synthesis, and excellent yields with reusability of the catalyst make the methodology highly effective for the synthesis of chromeno[4,3-e][1,3]oxazine derivatives. To the best of our knowledge, this is the first Letter for the synthesis of chromeno[4,3-e][1,3]oxazines using 3-hydroxy coumarin. 相似文献