부산대학교 도서관

The cyclic amidine 3 was used as a precursor in this research, which was synthesized by chlorination of compound 1, followed by ring closure with hydrazine hydrate. Cyclization of amidine compound 3 with acetylacetone, ethyl cyanoacetate, chalcone analogue 6 and benzylidenemalononitrile ( 8) tolerated the expected tricyclic pyrimidines 4, 5, 7 and 9, respectively. Reaction of 3 with ammonium thiocyanate followed by cyclization of the product 10 with DMF, ethyl chloroformate and chloroacetyl chloride afforded triazine derivatives 11- 13, respectively. Nucleophilic substitution of the later compound with EtONa gave ethyl methyl ether derivative 14. The benzamide derivative 15 was obtained by reaction of 3 with benzoylisothiocyanate or benzoylation of compound 10 with benzoyl chloride. Finely, heterocylization of 15 in the presence of EtN gave the triazine derivative 16. Graphical abstract: 6-(4-Chlorophenyl)-4-(4-isopropylphenyl)-1 H-pyrazolo[3,4- b]pyridin-3-amine ( 3) was used as the starting material for the synthesis of pyrido[2′,3′:3,4]pyrazolo[1,5- a]pyrimidine and pyrido[2′,3′:3,4]pyrazolo[1,5- a][1,3,5]triazine derivatives via cycloaddition and intermolecular cyclization reactions. [ABSTRACT FROM AUTHOR]