Formation of 1-methyl[1,2,4]triazolo[4,3-a] quinazolin-5(4H)-ones by reaction of 2-hydrazinoquinazolin-4(3H)-ones with acetylacetone

Abstract Reaction of 2-hydrazinoquinazolin-4(3 H )-ones with acetylacetone results in the formation of 1-methyl[1,2,4]triazolo[4,3- a ]quinazolin-5(4 H )-ones instead of 2-(3,5-dimethyl-1 H -pyrazol-1-yl)quinazolin-4(3 H )-ones. Under similar conditions, the 7-hydrazinocarbonyl group in quinazolin-4(3 H )-one moiety is transformed into a pyrazole derivative, which can be replaced by amine with the amide formation.