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1.
Brigitte Bouteau Jean-Charles Lancelot Max Robba 《Journal of heterocyclic chemistry》1990,27(6):1649-1651
The synthesis of 1,2,4-triazolo[4,3-a] and [2,3-a]pyridines 7, 8 was achieved by cyclization of 2-hydrazino-8-nitropyridine 3a with formic acid. The 4,5,6,7-tetrahydro-1,2,4-triazolo[2,3-a]pyridine 13 and 8-amino-1,2,4-triazolo[2,3-a]pyridine 9 were obtained by catalytic hydrogenation. The reduction of triazolo pyridine 8 using stannous chloride led to the intermediate compound 10 which with acetic anhydride afforded 8-acetylamino-5-chloro-1,2,4-triazolo[2,3-a]pyridine 10a . The structure of the derivatives was determined by 1H-nmr (DMSO-d6). 相似文献
2.
The isomerization of s-triazolo[4,3-a]pyridines into s-triazolo[1,5-a]pyridines is greatly facilitated by electron withdrawing nitro substituents in the pyridine ring and retarded by electron donating amino groups. 相似文献
3.
Maria Teresa Cocco Cenzo Congiu Valentina Onnis Antonio Maccioni 《Journal of heterocyclic chemistry》1991,28(3):797-800
The reaction of N1-acyl-2-ethoxycarbonylacetamidrazones with ethyl ethoxymethylenecyanoacetate (EMCA) has been examined. The acetamidrazone 1a reacts with EMCA in boiling dimethyl sulphoxide to give the 1,2,4-triazolo[4,3-a]pyridin-3(2H)-one 2 in excellent yield. Similarly from the amidrazones 1b-h the 1,2,4-triazolo[4,3-a]pyridines 3b-h were obtained. When the reaction between the amidrazones and EMCA was performed in ethanolic solution, the 6-(2-acylhydrazino)-pyridines 4 were isolated. Ring closure of 4 afforded the 1,2,4-triazolo[4,3-a]pyridines. 相似文献
4.
Yuh-Wen Ho 《中国化学会会志》1999,46(6):955-962
Coupling the diazonium salt of 3-amino-2-cyano-4,6-dimethylthieno[2,3-b]pyridine 1 with malononitrile 2 gave 2-cyano-3-(hydrazonomalononitrile)-4,6-dimethylthieno[2,3-b]pyridine 3 which then reacted with hydrazine compounds 4a-4h to yield corresponding 2-cyano-3-(3,5-diamino-1-substituted-pyrazol-4-yl)azo-4,6-dimethylthieno[2,3-b]pyridines 5a-5h. The 2-cyano-3-(2-amino-5,7-disubstituted-pyrazolo-[1,5-a]pyrimidine-3-yl)azo-4,6-dimethylthieno[2,3-b]pyridines 7a-7f were obtained in good yield by the cyclocondensation reaction of 2-cyano-3-(3,5-diamino-pyrazol-4-yl)azo-4,6-dimethylthieno[2,3-b]pyridine 5a with the appropriate 1,3-diketones 6a-6f under acidic condition. 相似文献
5.
Cvetka Turk Jury Svete Amalija Golobi
Ljubo Goli
Branko Stanovnik 《Journal of heterocyclic chemistry》1998,35(3):513-518
4( R )-(6-Chloro-s-triazolo[4,3-b]pyridazinyl-3)-1,4-furanoses 10 and 11 , 5( R )-(6-chloro-s-triazolo[4,3-b]pyridazinyl-3)-1,5-pyranose 13 , and 2(S),3( R )-dihydro-5-(6-chloro-s-triazolo[4,3-b]pyridazinyl-3)-2,3-O-isopropylidenefuran ( 12 ) were prepared by cyclization of hydrazones 6–9 obtained from 6-chloro-3-hydrazinopyridazine ( 1 ) and aldofuranoses 2, 3 and 4 , and aldopyranose 5 . 相似文献
6.
A series of fused 1,2,4-triazoles has been prepared by oxidative intramolecular cyclization of heterocyclic hydrazones with selenium dioxide. General applicability of this practical protocol was confirmed by the synthesis of moderate to good yields of 1,2,4-triazolo[4,3-a]pyridines, 1,2,4-triazolo[4,3-a]pyrimidines, 1,2,4-triazolo[4,3-a]pyramidines, and 1,2,4-triazolo-[4,3-a]quinoxa lines. All compounds were tested in vitro for their cytotoxic activity against HCT-116, A549, and Colo-205 cell lines. Two compounds, 3-(4-methoxyphenyl)-7-methyl-[1,2,4]triazolo[4,3-a]pyridine and 1-(4-methoxyphenyl)-[1,2,4]triazolo[4,3-a]quinoxaline, showed potent antiproliferative activity against the three cell lines. 相似文献
7.
s-Triazolo[4,3-b]pyridazine (I) reacted with cyclohexene under the influence of ultraviolet light to yield 4a,5,7,8,8a,9-hexahydro-9-methylene-6H-s-triazolo[1,5-a]indole (IV) and 9-cyanomethyl-4a,5,7,8,8a,9-hexahydro-6H-s-triazolo[1,5-a]indole (V). These products were formed by the addition of the alkene to the 1,8 positions of I with a concurrent cleavage of the N4? N5 bond. Similar additions were observed with cyclopentene and 2,3-dimethyl-1,3-butadiene. The isomeric s-triazolo[2,3-b]pyridazine (III) reacted with cyclohexene to form an isomer of IV, 4a,5,7,8,8a,9-hexahydro-9-methylene-6H-s-triazolo[4,3-a]indole (XV) and two [2 + 2] cycloadducts (XVI and XVII). 相似文献
8.
Reactions of ketene dithioacetals, 1-[1-substituted 2,2-bis(methylthio)ethenyl]pyridinium 1a-i or -isoquinolinium 2a,b iodides with aromatic N-imines, 1-aminopyridinium 3a-1,1 -aminoquinolinium ( 4 ), and 2-amino-isoquinolinium ( 5 ) mesitylene sulfonates gave the corresponding 2-methylthioimidazo[1,2-a]pyridines 9a-k , 2-methylthiopyrazolo[1,5-a]pyridines 11a-q , 2-methylthioimidazo[2,1-a]isoquinoline derivatives 10a,b and 2-methylthiopyrazolo[1,5-a]quinoline ( 12 ). The benzoyl compounds, 1-[1-benzoyl-2,2-bis(methylthio)ethenyl]-pyridinium iodides 1g,h,i reacted with N-imine 3a to give the 3-benzoyl-2-methylthioimidazo[1,2-a]pyridines 9h-k . The reaction of pyridinium ketene dithioacetals 1a,f,g (R1 = COOEt, COPh, and CN) with substituted pyridinium N-imines having an electron-withdrawing group on the pyridine ring afforded only the corresponding pyrazolo[1,5-a]pyridine derivatives 11j-r in good yields. Reactions of ketene dithioacetals with various S-imines are also described. Possible mechanisms for the formation of 9 and 11 are described. 相似文献
9.
Pyrolytic decomposition of ketone 2-heterylhydrazones has been shown to be unsatisfactory for the preparation of fused s-triazole derivatives. The introduction of more diversified substituents into the s-triazolo[4, 3-a]pyrazine and s-triazolo[4,3-a]quinoxaline systems has been accomplished and some reactions and spectral characteristics of these ring systems are reported. Isomerization of the s-triazolo[4, 3-a]pyrazine system to the s-triazolo[1,5-a]pyrazine system is described. 相似文献
10.
Yuh-Wen Ho 《中国化学会会志》1999,46(1):91-96
The reaction of 3-amino-4,6-dimethyl-2-thieno[2,3-b]pyridine carbohydrazide ( 1 ) with appropriate chalcones 2a-2d in the presence of acid catalyst produced the corresponding 3-amino-2-[(3,5-disubstituted-pyrazolin-1-yl)carbonyl]-4,6-dimethylthieno[2,3-b]pyridines 3a-3d . 3-Amino-2-[(3-substituted-pyrazolin-1-yl)carbonyl]-4,6-dimethylthieno[2,3-b]pyridines 7a, 7b were also obtained by the cyclization reaction of carbohydrazide 1 with Mannich base derivatives 6a, 6b under basic condition. 相似文献
11.
Reaction of 2-methyl-2-thiopseudourea sulfate with 1-hydrazinophthalazine gave 3-amino-s-triazolo[3,4-a] phthalazine in good yield. 1-Amino-4-methyl-s-triazolo[4,3-a]quinoxaline and 1-amino-s-triazolo[4,3-a]quinoxalin-4(5H)one were similarly perpared. 相似文献
12.
Mosselhi A. N. Mosselhi 《Monatshefte für Chemie / Chemical Monthly》2002,29(1):1297-1304
Reaction of 6-Amino-2-thiouracil with hydrazonoyl halides yielded regioselectively 7-amino-1,3-disubstituted-1,2,4-triazolo[4,3-a]pyrimidine derivatives. Upon treatment with methyl (Z)-2-benzoylamino-3-dimethylaminopropenoate, the corresponding methyl (Z)-2-benzoylamino-3-([1,2, 4]triazolo[4,3-a]pyrimidin-7-yl)-amino propenoates were obtained which cyclized in the presence of sodium ethoxide to afford novel derivatives
of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-(1H,8H)-diones. 相似文献
13.
Preparation of styryl derivatives of 2-phenyl-4H-1,2,4-triazolo [1,5-a]pyridine 7-Methyl-2-phenyl- and 2-(3-chloro-4-methylphenyl)-4H-1,2,4-triazolo[1,5-a]-pyridines react with anils of aromatic aldehydes in the presence of dimethyl-formamide and potassium hydroxide at 20–45° to yield the 2-phenyl-7-styryl- and 2-(2-chloro-stilben-4-yl)-4H-1,2,4-triazolo [1,5-a]pyridines respectively (‘Anil Synthesis’). Further, the Schiff's bases derived from o-chloroaniline and 2-(p-formyl-phenyl)- and 7-formyl-2-phenyl-4H-1,2,4-triazolo [1,5-a]pyridine yield, with methyl- and with p-tolyl-substituted heterocycles, the corresponding heterocyclic substituted styryl and stilbenyl derivatives. 相似文献
14.
The synthesis of a number of 8-substituted- and 3-methyl-8-substituted-.s-triazolo[4,3-a]-pyrazines as model molecules for an isomer of formyein (i.e., 8-amino-3-(β-D-ribofuranosyl)-s-triazolo[4,3-a ]pyrazine ( 2 )) and some of its derivatives (including aglycone) is reported. The C-8 subslituents include amino ( 3a and 4a ), chloro ( 3b and 4b ), hydroxy (as the 8 -ones 8a and 9a ), mercapto (as the 8 -thiones 8c and 9c ), hydroxylamino ( 3e and 4e ), selenoxy (as the 8 -selenones 8d and 9d ), metlioxy ( 3g and 4g ), and thiomethoxy ( 3h and 4h ). Also described are 7-methyl-s-triazolo[4,3-a]pyrazin-8(7H) one ( 8b ) and its 3-methyl derivative ( 9b ) together with imidazo[1,2-g]-s-triazolo[4,3-a]pyrazine ( 10a ) and its 3-methyl derivative ( 10b ). Complete spectral data for all of these molecules is presented. 相似文献
15.
Open-chain C-nucleosides, 1-(s-triazolo[4,3-x]azinyl-3)polyols 13–18 were prepared by one-pot synthesis from hydrazinoazines 20a,c and various D-aldoses 1–6. No protective groups were required for these transformations. 1-(s-Triazolo[4,3-b]pyridazinyl-3)-D-xylo-tetritol (15a) was isolated and characterised in the form of its 4-O-triphenylmethyl derivative 19. Reaction of hydrazinopyridazines 20a,b with methyl 2,3-di-O-acetyl-L-threuronate ( 22 ), followed by treatment with bromine, gave the corresponding (2R,3S)-2,3-diacetoxy-3-(s-triazolo[4,3-b]pyridazinyl-3)propanoic acid methyl esters 24a,b. Acetonisation of 1-(6-chloro-s-triazolo[4,3-b]pyridazinyl-3)-D-gluco-pentitol ( 17a ) gave a mixture of isomeric bis-acetonides 25 and 26 , while acetonisation of 1-(6-chloro-s-triazolo[4,3-b]pyridazinyl-3)-D-manno-pentitol ( 18a ) gave acetonide 27 as a single isomer. 相似文献
16.
Ronald J. Pugmire James C. Smith David M. Grant Branko Stanovnik Miha Tiler 《Journal of heterocyclic chemistry》1976,13(5):1057-1062
Carbon-13 nmr techniques have been employed to study imidazo[1,2-a]pyridine, imidazo-[ 1,2-b]pyridazine, s-triazolo[4,3-b]pyridazine, and s-triazolo[ 1,5-b]pyridazine and their N-1 quaternized derivatives. The data on quaternized derivatives have been analyzed to determine the tautomeric structures possible in the protonated derivatives. The data suggest that protonation at the bridgehead nitrogen does not occur in these compounds and, of the possible tautomerie forms, the N-1 tautomer predominates. 相似文献
17.
Yasumitsu Tamura Joong-Hyup Kim Yasuyoshi Miki Hironori Hayashi Masazumi Ikeda 《Journal of heterocyclic chemistry》1975,12(3):481-483
New routes to the v-triazolo[1,5-a]pyridine and pyrazolo[1,5-a]pyridine ring systems are described. Treatment of the N-amine salts of 2-picolinealdehyde oxime or 2-pyridyl ketone oximes with polyphosphoric acid gave v-triazolo[1,5-a]pyridines in fair yields. Treatment of 2-picolyl ketones or their oximes with O-mesitylenesulfonylhydroxylamine produced directly pyrazolo-[1,5-a]pyridines. These reactions were extended to the quinoline cases. 相似文献
18.
Mosselhi A. N. Mosselhi 《Monatshefte für Chemie / Chemical Monthly》2002,133(10):1297-1304
Summary. Reaction of 6-Amino-2-thiouracil with hydrazonoyl halides yielded regioselectively 7-amino-1,3-disubstituted-1,2,4-triazolo[4,3-a]pyrimidine derivatives. Upon treatment with methyl (Z)-2-benzoylamino-3-dimethylaminopropenoate, the corresponding methyl (Z)-2-benzoylamino-3-([1,2, 4]triazolo[4,3-a]pyrimidin-7-yl)-amino propenoates were obtained which cyclized in the presence of sodium ethoxide to afford novel derivatives
of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-(1H,8H)-diones.
E-mail: mosselhi@chem-sci.cairo.eun.eg
Received February 8, 2002; accepted (revised) March 18, 2002 相似文献
19.
Thomas Novinson Takayuki Okabe Roland K. Robins Phoebe Dea 《Journal of heterocyclic chemistry》1975,12(6):1187-1190
The condensation of 3-amino-5-benzylthio-s-triazole ( 2 ) with acetylacetone in refluxing acetic acid has been reported to have given 3-benzylthio-5,7-dimethyl-s-triazolo[4,3-a]pyrimidine ( 3 ). However, it has now been established, with the aid of 13C spectra and a modification of the original synthetic work, that only 2-benzylthio-5,7-dimethyl-s-triazolo[1,5-a]pyrimidine ( 4 ) can be obtained by this method of condensation. The erroneously reported, but previously unknown 6 was synthesized and its structure and that of 4 was firmly established by ir, uv, pmr,13 C nmr, tlc and mixed melting point data. The correct structures of 3-mercapto-5,7-dimethyl-s-triazolo-[4,3-a]pyrimidine ( 5 ) and 2-mercapto-5,7-dimethyl-s-triazolo[1,5-a]pyrimidine ( 6 ) were also established and the facile rearrangement of 5 to 6 was demonstrated. 相似文献
20.
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