共查询到20条相似文献,搜索用时 437 毫秒
1.
E. V. Babaev A. A. Bush I. A. Orlova V. B. Rybakov I. Iwataki 《Russian Chemical Bulletin》2005,54(1):231-237
A new procedure was developed for the synthesis of 2-aminothiazolo[3,2-a]pyridinium salts 8 by the reaction of 2-halo-N-phenacylpyridinium salts with KSCN. The anion compositions of salts 8 were studied by ion chromatography. Acylation of salts 8 afforded representatives of the previously unknown bicyclic mesoionic thiazolo[3,2-a]pyridinium 2-imidate system 9. The three-dimensional structures of 2-amino-3-(p-bromobenzoyl)thiazolo[3,2-a]pyridinium thiocyanate and N-trifluoroacetyl-3-(p-nitrobenzoyl)thiazolo[3,2-a]pyridinium 2-imidate were established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 226–232, January, 2005. 相似文献
2.
The method developed for the synthesis of thiazolo[3,2-a]pyridinium salts has been extended to the first synthesis of simple thiazolo[3,2-a]pyrimidinium, thiazolo[3,2-a]-pyrazinium and thiazolo[2, 3-b]benzo[d]thiazolium salts. No method could be found for the cyclization of 4′-bromo-2-(2-benzoxazolylthio)acetophenone to the thiazolo[2,3-b]-benzoxazolium system. 相似文献
3.
Dyachenko V. D. Dyachenko A. D. Chernega A. N. 《Russian Journal of Organic Chemistry》2004,40(3):397-406
Cyclopentylidene- and cyclohexylidene(cyano)acetamides reacted with malononitrile and cyano-(thioacetamide) according to the Michael pattern with exchange of the methylene components to give substituted 1-amino-2,6,6-tricyano-1,3-cyclohexadienes and thieno[2,3-d]pyrimidine-4(3H)-thiones. Condensation of cyclopentylidene- and cyclohexylidene(cyano)acetamide with 1,3-dicarbonyl compounds afforded 4,6-di-methyl-3-cyanopyridine-2(1H)-thione and morpholinium 4-methyl-6-oxo-3-cyano-1,6-dihydropyridine-2-thiolate which were converted into substituted 2-alkylsulfanylpyridines, thieno[2,3-b]pyridines, thiazolo[3,2-a]pyridine, and 2H-[1,3]thiazino[3,2-a]pyridine. 相似文献
4.
Three thieno-fused analogues of benzo[a]quinolizinium ( 1 ), thieno[3,2-a]- and thieno[2,3-a]quinolizinium 4 and 5 and thiazolo[2,3-a]isoquinolinium ( 6 ), were synthesized by photocyclization of 1-(2-thienylvinyl)pyridinium salts 9a and 9b and 3-styrylthiazolium salt 9c , respectively. The nitration of the compounds 4, 5 , and 6 occurred predominantly at positions 2, 3, and 7, respectively, while the nitro group was introduced into the 8- and 10-positions of 1 in the ratio of 68:32. The nmr and uv spectral properties and reduction potentials of 4–6 were also compared with those of the parent compound 1 . 相似文献
5.
Nehal A. Hamdy Hatem A. Abdel-Aziz Ahmad M. Farag Issa M. I. Fakhr 《Monatshefte für Chemie / Chemical Monthly》2007,138(10):1001-1010
Summary. 3-(3-Methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile was synthesized by refluxing ethyl 3-methylthiazolo[3,2-a]benzimidazole-2-carboxylate, acetonitrile, and sodium hydride. Treatment of 3-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile with phenyl isothiocyanate, in the presence of KOH, furnished the corresponding potassium
salt which was converted into thioacetanilide derivative upon neutralization. The thioacetanilide derivative reacts with α-chloroacetylacetone
and ethyl α-chloroacetoacetate to give the 1,3-thiazole derivatives, while the reaction of the'thioacetanilide derivative
with hydrazonyl chlorides gave 1,3,4-thiadiazole derivatives. On the other hand, 3-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile reacted with the diazonium salt of both 3-phenyl-5-amino-(1H)-pyrazole and 5-amino-l,2,4-(1H)-triazole to afford the corresponding hydrazones. The latter hydrazones underwent an intramolecular cyclization upon boiling
in pyridine to give pyrazolo[5,1-c]-1,2,4-triazine and 1,2,4-triazolo[5,1-c]-1,2,4-triazine derivatives. Moreover, the behavior of thiazolo[3,2-a]benzimidazol-3(2H)-one towards phenyl isothiocyanate followed by the reaction with α-chloroketones or hydrazonyl chlorides was investigated.
Some of the latter compounds exhibited moderate effects against some bacterial and fungal species. 相似文献
6.
Yu. M. Volovenko G. G. Dubnina A. N. Chernega 《Chemistry of Heterocyclic Compounds》2004,40(1):94-100
Reactions of 3,4-dichloro-N-R-maleimides with substituted thiouracils at 40°C gave a 1:1 mixture of isomers of pyrrolothiazolopyrimidinetriones. Under conditions of thermodynamic control (100°C, 5 h) only pyrrolo[3',4':4,5]thiazolo[3,2-a]pyrimidine-4,6,8-triones were formed, hydrolysis of which followed by decarboxylation gave 5-oxo-5H-thiazolo[3,2-a]pyrimidine-2-carboxamide. The structure of N2-phenyl-6-methyl-5-oxo-5H-thiazolo[3,2-a]pyrimidine-2-carboxamide was confirmed by X-ray crystallography. Analogous cyclization of 3,4-dichloro-N-R-maleimides with 2-thioxoquinazol-4-one also gave a mixture of two isomers which were successfully separated by fractional crystallization. 相似文献
7.
Uro Urleb 《Journal of heterocyclic chemistry》1998,35(3):693-697
Heterocyclic isothiocyanates 1,5,9 , bearing an o-ester group were converted to thiourea derivatives 2a-c, 6a-b , and 10a-b , respectively, using β-aminoalcohols, and to the fused ring systems, e.g., thieno[3,2-d]pyrimidine 4a-b , pyrido[2,3-d]pyrimidine 8 , pteridine 11a , thiazolo[3,2-a]pyrido[2,3-d]pyrimidine 7a-b , and thiazolo[3,2-a]mieno[3,2-d]pyrirnidine 3a-c , derivatives. 相似文献
8.
A. D. Dyachenko S. M. Desenko V. D. Dyachenko A. N. Chernega 《Chemistry of Heterocyclic Compounds》2004,40(5):650-659
Partially hydrogenated thiazolo[3,2-a]pyridines have been synthesized by the interaction of functionally substituted ammonium di- and tetrahydropyridine-2-thiolates with bromocyclohexanone. The structure of 6,8-dicyano-3-hydroxy-5-oxo-1,3-tetramethylene-2,3,4,5,6,7-hexahydrospiro[thiazolo[3,2-a]pyridine-7,1'-(4'-methylcyclohexane)] has been determined by X-ray crystallography. 相似文献
9.
A new and efficient method for the synthesis of hitherto unreported spiro[benzo[4,5]thiazolo[3,2-a]chromeno[2,3-d]pyrimidine-14,3′-indoline]-1,2′,13(2H)-triones was developed via the Domino Knoevenagel condensation–Michael addition–intermolecular cyclization sequences of isatin derivatives, cyclohexane-1,3-diones, and 2-hydroxy-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones, employing 12-tungstophosphoric acid (H3PW12O40) as an effective and inexpensive catalyst. 相似文献
10.
Iodination of 2-[allyl(methallyl)sulfanyl]-6-(trifluoromethyl)pyrimidin-4(3H)-ones was accompanied by cyclization to 2,3-dihydro[1,3]thiazolo[3,2-a]pyrimidin-4-ium triiodides. 3-(Iodomethyl)-3-methyl- 7-oxo-5-(trifluoromethyl)-2,3-dihydro[1,3]thiazolo[3,2-a]pyrimidin-4-ium triiodide was reduced with sodium iodide to 3,3-dimethyl-7-oxo-5-(trifluoromethyl)-2,3-dihydro[1,3]thiazolo[3,2-a]pyrimidin-4-ium iodide. 相似文献
11.
Yvonne Syha Charlene Valmalle Jan W. Bats Michael Kock Mona Abdel-Tawab Manfred Schubert-Zsilavecz 《Monatshefte für Chemie / Chemical Monthly》2006,137(10):1357-1364
Summary. Although various thiazoles are known in literature for their biological and pharmacological properties only a few multi-step
synthesis pathways for the preparation of thiazolo[3,2-a]pyrimidinones have been reported, which are tedious and time-consuming. An alternative synthesis pathway is described, which
allows the preparation of 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-ones in a one-step process based on a Michael-type tandem reaction. By heating of 2-thiobarbituric acid with ethyl 4-bromocrotonate in ethanol at 60°C for 2 h, a 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one was obtained in 73% yield, whereas carrying out the reaction at room temperature results in the formation
of an unstable unsaturated ester. The structures of both, the α,β-unsaturated ester as well as the 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one were confirmed by NMR spectroscopy. Additionally, the structure of the 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one was investigated by single-crystal X-ray analysis. The described approach offers a significant improvement
over previously reported synthesis pathways because it allows the simple preparation of 2,3-dihydrothiazolo[3,2-a]pyrimidin-5-ones with good yields in a one-step reaction. 相似文献
12.
Reaction of thiazolo[3,2-a]pyridinium salt 1 with secondary amines, depending on the reaction condition, may result in both stable pseudo bases 2 as addition products and thiazolyl-dieneamines 4 as products of ring opening. The ambident reactivity of the title system is interpreted by frontier orbital theory. 相似文献
13.
L. M. Potikha A. R. Turelyk V. A. Kovtunenko A. V. Turov 《Chemistry of Heterocyclic Compounds》2010,46(2):223-231
A method for the synthesis of derivatives of [1, 3]thiazolo[3,2-a]pyridines, pyrido[2,1-b][1, 3]benzo-thiazole, [1, 3, 4]thiadiazolo[3,2-a]pyridine, and [1, 2, 4]triazolo[4,3-a]pyridine, which includes base initiated cyclization of quaternary azolium salts, formed by the interaction of (Z)-1,3-diaryl-4-bromo-2-buten-1-ones with 1-alkyl-1H-1,2,4-triazoles, 4-methyl-1,3-thiazole, 1,3-benzothiazole, and N-phenyl-1,3,4-thiadiazole-2-amine.
Derivatives of 2-chloroimidazo[1,2-a]pyridine were obtained when 5-chloro-1-methyl-1H-imidazole was used. 相似文献
14.
Remizov Yu. O. Pevzner L. M. Petrov M. L. 《Russian Journal of General Chemistry》2019,89(10):2151-2153
The reaction of 5-aminomethyl-4-(1,2,3-thiadiazol-4-yl)furan-2-carboxylic acid ethyl ester with bases has given ethyl 5-sulfanylidene-4,5,6,7-tetrahydrofuro[2,3-c]pyridine-2-carboxylate as a result of intramolecular 6-endo-dig-cyclization of thioketene generated in situ with an internal CH2NH2 nucleophile. The obtained ester has been alkylated with iodomethane at the sulfur atom to form ethyl 5-methylsulfanyl-4,7-dihydrofuro[2,3-c] pyridine-2-carboxylate. The Hantzsch reaction with ω-bromoacetophenone has resulted in the formation of 7-ethoxycarbonyl-3-phenylfuro[3,2-d[1,3]thiazolo[3,2-a]pyridin-4-ium bromide.
相似文献15.
By use of concentrated sulfuric acid rather than hydrobromic acid as the cyclizing medium, good yields of the thiazolo[3,2-a]quinolinium ion and its derivatives may be obtained from α-(2-quinolylthio) ketones or acetals. In the same way, α-(1-isoquinolylthio) and α-(6-phenanthridylthio) ketones afford thiazolo[2,3-a]isoquinolinium and thiazolo-[3,2-f]phenanthridinium salts. 相似文献
16.
Nehal A. Hamdy Hatem A. Abdel-Aziz Ahmad M. Farag Issa M. I. Fakhr 《Monatshefte für Chemie / Chemical Monthly》2007,60(4):1001-1010
3-(3-Methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile was synthesized by refluxing ethyl 3-methylthiazolo[3,2-a]benzimidazole-2-carboxylate, acetonitrile, and sodium hydride. Treatment of 3-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile with phenyl isothiocyanate, in the presence of KOH, furnished the corresponding potassium
salt which was converted into thioacetanilide derivative upon neutralization. The thioacetanilide derivative reacts with α-chloroacetylacetone
and ethyl α-chloroacetoacetate to give the 1,3-thiazole derivatives, while the reaction of the'thioacetanilide derivative
with hydrazonyl chlorides gave 1,3,4-thiadiazole derivatives. On the other hand, 3-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile reacted with the diazonium salt of both 3-phenyl-5-amino-(1H)-pyrazole and 5-amino-l,2,4-(1H)-triazole to afford the corresponding hydrazones. The latter hydrazones underwent an intramolecular cyclization upon boiling
in pyridine to give pyrazolo[5,1-c]-1,2,4-triazine and 1,2,4-triazolo[5,1-c]-1,2,4-triazine derivatives. Moreover, the behavior of thiazolo[3,2-a]benzimidazol-3(2H)-one towards phenyl isothiocyanate followed by the reaction with α-chloroketones or hydrazonyl chlorides was investigated.
Some of the latter compounds exhibited moderate effects against some bacterial and fungal species. 相似文献
17.
Refluxing 3-amino-2-iminonaphtho[1,2-d]thiazole ( 1 ) with diethyl oxalate ( 2a ) in a 2:1 molar ratio in dry pyridine provided 2,2′-binaphtho[1′,2′:4,5]thiazolo[3,2-b][1,2,4]triazole ( 3 ). On the other hand, when 1 was treated with excess amount of 2a in dimethylformamide, it afforded ethyl naphtho[1′,2′:4,5]thiazolo[3,2-b][1,2,4]triazole-2-carboxylate ( 4a ) on heating and ethyl N-(2-iminonaphtho[1,2-d]thiazol-3-yl)oxamate ( 5 ) by stirring at room temperature. Cyclization of 5 upon fusion led to the formation of 3-hydroxy-2H-naphtho-[1′,2′:4,5]thiazolo[3,2-b][1,2,4]triazin-2-one ( 6 ). Compound 6 could also be prepared directly from 1 by refluxing either with 2a neatly, in glacial acetic acid or with oxalic acid ( 2b ) in the same medium. The acid form of 4a might be obtained from 1 and 2b on heating in dimethylformamide, but it was decarboxylated to naphtho-[1′,2′:4,5]thiazolo[3,2-b][1,2,4]triazole ( 4b ) during the reaction. 相似文献
18.
T. Beresneva S. Belyakov E. Abele E. Lukevics 《Chemistry of Heterocyclic Compounds》2011,46(11):1400-1404
The mechanism of the unexpected formation of 3-methyl derivatives of imidazo[2,1-b]thiazoles in the system 2-mercaptoimidazole–1,3-dichloroacetone–solid K2CO3–solid KI–18-crown-6–toluene has been studied. The structure of 3-methyl[1,3]thiazolo[3,2-a]benzimidazole has been confirmed using X-ray structural analysis. 相似文献
19.
Natural abundance 13C NMR chemical shifts have been experimentally determined for a series of mesoionic thiazolo[3,2-a]pyrimidine-5,7-diones. The spectral data are compared with those of related mesoionic dihydrothiazolo[3,2-a]pyrimidine-5,7-diones and mesoionic 1,3,4-thiadiazolo[3,2-a]pyrimidine-5,7-diones. Resonable correlation between the observed 13C NMR chemical shifts and CNDO/2 total charge densities have been obtained for the different carbon atoms of 8-methylthiazolo[3,2-a]pyrimidine-5,7-dione. 相似文献
20.
Formic acid-phosphorus pentoxide was effective for the preparation of 5,7-dimethyl[1,3,4]thiadiazolo- and -[1,3]thiazolo[3,2-a]pyrimidin-4-ium salts. Further, the pyrimidine ring transformation and the isocyanation of 5imino-6H-[1,3,4]thiadiazolo- and -[1,3]thiazolo[3,2-a]pyrimidin-7-ones were carried out in the presence of formic acid and triethyl orthoformate, respectively. 相似文献