M. A. Elneairy, M. Gad-Elkareem, A. M. Taha
Aug 1, 2005
Citations
0
Influential Citations
14
Citations
Journal
Journal of Sulfur Chemistry
Abstract
Pyridine-2(1H)-thione 1 reacted with phenyl isothiocyanate to give pyrido[2,3-d]pyrimidine derivative 3. Compound 3 reacted with halogen containing compounds 4a–d and methyl iodide in dimethylformamide/potassium hydroxide solution at room temperature to give 2,7-bisalkylthiopyrido[2,3-b]pyrimidine derivatives 5a–d and 9, respectively. Compounds 5a–d could be cyclized into thienopyrido[2,3-d]pyrimidine derivatives 6a–d by boiling with ethanolic potassium hydroxide solution. Compound 6a reacted with acetic anhydride or formic acid and gave the corresponding pyrimido[4″,5″:4′,5′]thieno[3′,2′:5,6]pyrido[2,3-d]pyrimidine derivatives 8a,b. Compound 9 reacted with hydrazine hydrate to yield pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivative 11 which could be reacted with nitrous acid and dimethylformamide-dimethylacetal (DMF-DMA) and gave the final isolable products corresponding to the pyrazolo[4′,3′:5,6]pyrido[2,3-d]tetrazolo-[5,1-b]pyrimidine and pyrimido[1″,2″:1′,5′]pyrazolo[4′,3′:5,6]pyrido[2,3-d]1 2 4triazolo-[4,3-b] pyrimidine derivatives 13 and 17, respectively. Compound 11 also reacted with some β-dicarbonyl compounds such as acetylacetone (18) and ethyl acetoacetate (20) to yield the corresponding pyrimido[1″,2″:1′,5′]pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives 19 and 21, respectively. Finally, compound 11 reacted with chloroacetyl chloride (22) to give the corresponding imidazo[1″′,2″′:1″,5″]pyrazolo[4″,3″:5′,6′]pyrido[3′,2′:5,6]pyrimido[2,1-c]1 2 4triazine derivative 23.