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1.
The reaction of 2-aminothiazoles with ethyl acetoacetate in acetic or polyphosphoric acid gave a series of 5H-[1,3]thiazolo[3,2-a]pyrimidin-5-one derivatives which were nitrated with a mixture of nitric and sulfuric acid to 6-nitro-5H-[1,3]thiazolo[3,2-a]pyrimidin-5-ones, and the latter were reduced to the corresponding amines. 相似文献
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The one-pot, multicomponent synthesis of imidazopyridine and pyridopyrimidine fused heterocyclic systems from readily available diamines, l,l-bis(methylthio)-2-nitroethene, cyanoacetohydrazide and aromatic aldehydes in good to high yields is described. This protocol has the advantages of simple work-up, mild reaction conditions, absence of catalyst and provides an entry point to fused heterocyclic structures. 相似文献
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7-Oxo-7H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-5-carboxylate derivatives are biologically and pharmacologically useful heterocycles. An efficient synthetic methodology for this class of compounds was developed through catalyst-free, one-pot reactions between 2-aminothiadiazoles and dimethyl acetylenedicarboxylate (DMAD) in THF with the aid of ultrasound irradiation. The reactions show applicability to a wide range of substrates and high regioselectivity for the “7-one” products over their “5-one” isomers. Detailed reaction mechanisms were mapped out by theoretical modeling analysis based on density functional theory (DFT) calculations. Mechanistic studies indicate that the favored reaction pathway involves a sequence of hydrogen-bond directed Michael addition, synergistic proton transfer/five-membered ring opening, and intramolecular cyano hetero-Diels-Alder reactions. 相似文献
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Condensation of 2-amino-4-hydroxy-2-mercaptopyrimidine (2) hydrate and ethyl 4-bromocrotonate gave a mixture of ethyl 7-amino-2,3-dihydro-5-oxo-5H-thiazolo[3,2-a]pyrimidine-3-acetate (4) and 2a,3-dihydro-1-thia-5,8,8b-triazaacenaphthylene-4,7(2H)-dione (5) whereas reaction of 2 with 4-bromocrotononitrile afforded only 7-amino-2,3-dihydro-5-oxo-5H-thiazolo[3,2-a] pyrimidine-3-acetonitrile. Reaction of the tricycle 5 (which was isolated as a hemihydrate) with excess methyl iodide/potassium carbonate in dimethylformamide resulted in both ring hydrolysis and methylation to give 3,4-dihydro-1,7-dimethyl-4- [(methylthio)methyl]-2H-pyrimido[1,6-a]pyrimidine-2,6,8(1H,7H)-trione (10). Methylating 5 with excess methyl iodide/sodium methoxide in methanol also resulted in ring fragmentation and methylation but instead afforded methyl 7-methyl-amino-2,3-dihydro-5-oxo-7H-thiazolo[3,2-a]pyrimidine-3-acetate. The mechanistic aspects of these reactions are discussed. 相似文献
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M. A. Kukaniev U. Nurov S. Sh. Shukurov Yu. Khodzhibaev 《Russian Chemical Bulletin》1999,48(6):1143-1145
Convenient procedures were developed for the preparation of new 2-R-thio and 2-amino derivatives of 7-methyl-6-nitro-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidines and products of their condensation with aldehydes. 相似文献
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E. A. Kuznetsova S. V. Zhuravlev T. N. Stepanova V. S. Troitskaya 《Chemistry of Heterocyclic Compounds》1972,8(2):156-158
The 7-amino (IV) and 7-acetamido (I) derivatives of thiazolino[3,2-a]benzimidazole were synthesized. The IR spectra of I, its deutero derivative, and a number of intermediates were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 177–179, February, 1972. 相似文献
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Gein V. L. Gein L. F. Tsyplyakova E. P. Rozova E. A. 《Russian Journal of Organic Chemistry》2003,39(5):753-754
Russian Journal of Organic Chemistry - 相似文献
11.
Piergiorgio Pecorari Marcella Rinaldi Maria Paola Costi 《Journal of heterocyclic chemistry》1989,26(6):1701-1705
Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d]-[1,3]thiazino[3,2-a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4-dihydro-7,8-diamino-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6-diamino-2,3-dihydro-2-thioxo-4(lH)-pyrimidi-none with 1,3- or 1,2-dibromoalkane, respectively. 相似文献
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Noël R Vanucci-Bacqué C Fargeau-Bellassoued MC Lhommet G 《The Journal of organic chemistry》2005,70(22):9044-9047
[reaction: see text] The preparation of new chiral 6-carbonyl 2,3,8,8a-tetrahydro-7H-oxazolo[3,2-a]pyridines by an efficient two-step procedure is described. 相似文献
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Zhai X Zhao YF Liu YJ Zhang Y Xun FQ Liu J Gong P 《Chemical & pharmaceutical bulletin》2008,56(7):941-945
A series of novel N-anilino-5-methyl-2-(3-(5-(alkylaminomethyl)furan-2-yl-methylthio)propyl)-[1,2,4]triazolo-[1,5-a]pyrimidine-7-amine derivatives were synthesized and evaluated for their in vitro cytotoxicity against two cancer cell lines, Bel-7402 and HT-1080. Compounds 9, 14, 19 and 23 possessed marked cytotoxicity, especially 23 (with IC(50) values of 15.0 microM and 7.8 microM against Bel-7402 and HT-1080 cell lines, respectively), which had emerged as lead compound. The activity was found to depend strongly on substitution pattern of the side chains at C-2 position, and 4-triflouromethylanilino substituent at C-7 position was an option for anticancer potency. 相似文献
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Matsuoka M Segawa J Amimoto I Masui Y Tomii Y Kitano M Kise M 《Chemical & pharmaceutical bulletin》1999,47(12):1765-1773
A series of 7-substituted-6-fluoro-1-fluoromethyl-4-oxo-4H- [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid derivatives (2a-1) was prepared and evaluated for antibacterial activity. These compounds were obtained by deacylation of 4-benzoyloxy-2-(1-chloro-2-fluoroethyl)thio-6,7- difluoroquinoline-3-carboxylate (10) and subsequent intramolecular cyclization followed by substitution with cyclic amines and then hydrolysis. The intramolecular cyclization reaction of 18, one of the diastereomers (17, 18) revealed that the cyclization reaction proceeded through an inversion to afford (-)-11a in good chemical and optical yield. The enantiomers of 2a were prepared from the enantiomers of 11a, which were obtained by the optical resolution of the racemate using high-performance liquid chromatography (HPLC). Compounds 2a,b showed excellent in vitro and in vivo antibacterial activity against both gram-negative and gram-positive bacteria including quinolone and Methicillin-resistant Staphylococcus aureus. 相似文献
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S. P. Stanforth 《Journal of heterocyclic chemistry》1987,24(2):531-532
Treatment of 1-(2′-nitrophenyl)isoquinoline with hot triethylphosphite afforded indazolo[3,2-a]isoquino-line. 相似文献
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ZHAI Xin ZHANG Cun-long HE Lei LI Qi WANG Jiu-liang SHEN Xiao-li GONG Ping 《高等学校化学研究》2009,25(4):474-479
A series of novel N-anilino-2-substituted-5-methyl-[1,2,4]triazolo[1,5-a]pyrimidine-7-amine derivatives was prepared and evaluated for their in vitro antiproliferative activity against two cancer cell lines,Bel-7402 and HT-1080.Most of the compounds inhibited the cell proliferation at a low concentration.Seven compounds,VI5,VI7,VI10,and VI12―VI15,possessed marked antiproliferative activity superior to that of cisplatin.Of these seven initial hits,compound VI10 was the most active. 相似文献