Design, synthesis, and antimicrobial activity of some new pyrazolo[3,4‐ d ]pyrimidines

Abstract 2‐Benzyl‐ and 2‐aryloxymethyl‐3‐amino‐1‐phenyl‐pyrazolo[3,4‐ d ]pyrimidine‐4‐ones 5a–f have been synthesized by reacting the corresponding arylacetylamino derivatives 3a–f with hydrazine hydrate. Thionation of compounds 5d–f by action of P 2 S 5 in pyridine yielded 2‐aryloxy‐methyl‐3‐amino‐1‐pheny‐lpyrazolo[3,4‐ d ]pyrimidin‐4‐thions 6a–c . 2,5‐Diphenyl‐2,3‐dihydro‐1 H ‐pyrazolo[5′,1′:4:5]pyrazolo[3,4‐ d ]pyrimidine‐8‐one ( 8 ) was also obtained via reaction of ethyl‐2‐cinnamoylamino‐1‐phenyl‐pyrazole‐4‐car‐boxylate ( 7 ) with hydrazine hydrate. The prepared compounds were screened in vitro for their antimicrobial activity. Some of the tested compounds were found to be active at 100 μg/ml compared with reference compounds (Ampicillin and Trivid) as antibacterial agents and claforan as antifungal agent.