الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 140 |  |  |
| | | from | 140 | | |
Abstract
In the present work we synthesis of 3,6-diaminopyrazolo[3,4-b]pyridine derivatives by reaction of 2-amino-4-(2-chlorophenyl)-6-thiophenylpyridine-3,5-dicarbonitrile 1b with hydrazine hydrate, methyl hydrazine, aryl hydrazine, semicarbazide, thiosemicarbazide, m-chloro- benzoyl hydrazine, p-bromobenzoyl hydrazine and 2-cyanoethanoic acid hydrazide to yield 11a, 12a, 15a-c, 17-21 respectively, in good yield via thiophenol elimination and cyclization. In the same way, the reaction of 2-amino-4-(4-(2-amino-3,5-dicyano-6-thiophenylpyridin-4-yl)phenyl)-6-thiophenylpyridine-3,5-dicarbonitrile 8 with hydrazine hydrate or methyl hydrazine to give 22a and 22b respectively, via two mole from thiophenol elimination and cyclization. Diazotisation of 11a in the presence of conc. HNO3 afforded the diazonium salt 23a that reacted with β-naphthol, resorcinol, p-dihydroquinone and α-naphthol to give the corresponding azo-compounds, some of which was cyclised to pyrido[3\,2\:4,5]pyrazolo[3,2-c]-1,2,4-triazine derivatives 26a, 28, 30 respectively. Also, the diazonium salt 23a was reacted with active methylene derivatives, namely, malono nitrile, ethyl cyanoacetate, diethylmalonate and acetyl acetone in the presence of sodium acetate to yield the corresponding hydrazones (or their tautomers). The open chain derivatives was cyclised to pyrido[3\,2\:4,5]- pyrazolo[3,2-c]-1,2,4-triazine derivatives 32-35 respectively when heated in acetic acid. On the other hand, the reaction of compound 11a with ethyl aceto acetate, acetyl acetone, arylidenemalononitrile, ethyl m-chlorobenzylidene -cyanoacetate and α,β-unsaturated ketone 45 under reflux conditions afforded pyrido[3\,2\:4,5]pyrazolo[1,5-a]pyrimidine derivatives 39, 41, 43, 44 and 47 respectively . Finally, treatement of 11a with dimethyl N-cyanodithioimino carbonate 48 in ethanol and in presence of Et3N at refluxed temperature to give pyrido[2\,3\:3,4]pyrazolo[1,5-a]-1,3,5-triazine derivatives 49 in good yield.