Efficient Synthesis and Biological Evaluation of Some New Pyrazolo[1,5‐ <i>a</i> ]pyrimidine Derivatives as Antimicrobial Activity

Abstract A series of new pyrazolo[1,5‐ a ]pyrimidine 4 – 15 derivatives were synthesized starting from 3,5‐diaminopyrazole derivatives 3 a,b as precursor using a simple, efficient procedure, and screened for their in‐vitro antimicrobial activities. All the synthesized compounds were fully characterized by IR, 1 HNMR, 13 CNMR, MS spectral data, and elemental analysis. Among the investigated against the antimicrobial activity, compounds 4 b , 4 d , 4 e , 8 b , 9 and 12 showed the best activity. The remaining compounds were found to have weak activity against gram‐positive and gram‐negative.