A new synthesis of pyrazolo[1,5‐d][1,2,4]triazines from pyrazolecarboxylic acid hydrazides and carbonyl compounds. I

Abstract

Pyrazolo[1,5‐d][1,2,4]triazines were synthesized from pyrazolecarboxylic acid hydrazides and carbonyl compounds. Pyrazolecarboxylic acid N‐phenylhydrazide (1c) and formaldehyde gave not only the expected 4hn but 5, respectively. The methyl substituted hydrazides with acetone afforded hydrazones, pyrazolotriazines or 13 depending on the position of the substituents. The reduction of both products yielded pyrazolecarboxylic acid hydrazides.