Synthesis and biological studies of some benzopyrano[2,3-c]pyrazole derivatives

3-Chlorobenzopyrano[2,3-c]pyrazole (2) was prepared and reacted with sodium azide to give compound 3, whereas its reaction with benzoyl hydrazide, ethyl glycinate, anthranilic acid or o-phenylenediamine afforded the products 4-7, respectively. Compounds 8 and 9 were synthesized by the reaction of compound 2 with 2-mercaptobenzothiazole or piperidine. 3-Hydrazinobenzopyrano[2,3-c]pyrazole (10) was obtained and subjected to cyclization with different reagents such as CS,, benzoic acid, acetyl acetone and diethyl malonate to give compounds 11-14, respectively. Compound 10 was cyclized also with phenacyl cyanide, ylidenemalnnonitriles to afford the products 15-20, respectively. On the other hand, compound 10 was cyclized with 3-[bis(methylthio)methylene]pentane-2,4- or 1,1-dicyano 2,2-dimethylthioethylene to give the corresponding compounds 22 and 23 which in turn were reacted with some compounds containing active methylene groups to afford the corresponding compounds 24-27, respectively. The biological activities of some selected compounds were given. (C) 2000 Elsevier Science S.A. All rights reserved.