Synthesis and Reactions of 2-Carboxyvinyl-4-chloro-6,8- dibromoquinazoline and Some New Fused Triazolo-Quinazoline Derivatives

Synthesis of 2-carboxyvinyl-4-chloro-6,8-dibromoquinazoline (2) has been achieved via chlorination of the corresponding 6,8-dibromoquinazoline analog. The simple replacement of the chlorine atom at the position 4 of quinazoline nucleus with different amines has produced derivatives of the 4-heteroarylquinazoline and the fused quinazolino[4,3-c]quinazoline. The reaction of the chloroquinazoline derivative 2 with hydrazine hydrate and subsequent condensation with different aromatic aldehydes furnished a series of fused 5-substituted-[1,2,4]triazoloquinazoline derivatives. Finally, its reaction with acyl hydrazide (acetyl hydrazide) furnished the heterocyclic system 7,9-dibromo-3-methyl-[1,2,4]triazolo[ 4,3-c]Quinazolin-5-yl-2-propenoic acid.