Activated nitriles in heterocyclic synthesis. A novel synthesis of pyrazolo[1,5‐<i>a</i>]pyrimidines and pyrano[2,3‐<i>c</i>]pyrazoles

Abstract

Abstract Several new pyrazolo[1,5‐ a ]pyrimidines and pyrano[2,3‐ c ]pyrazoles were synthesized viathe reaction of the cinnamonitrile derivatives 1a‐c with 5‐amino‐3‐phenylpyrazole ( 1 ), 3‐amino‐2‐pyrazolin‐5‐one ( 2 ) and 3‐amino‐1‐phenyl‐2‐pyrazolin‐5‐one ( 22 ).