A simple and facile method for the synthesis of novel 5/7 trifluoromethyl-substituted 4(3H)-quinazolone regioisomers

The unsymmetrical 1,3-diketones 1 on reaction with malononitrile is resulted an interesting trifunctional intermediates 2 and 3. The intermediate 2 is hydrolyzed to give 2,6-dicarboxamido aniline 4 which on cyclisation gave two regioisomers of 1,2-dihydro-4(3H)-quinazolinones 5 and 6. The effect of substituents on compound 4 is characteristic for formation of regioisomers in different proportions. Each regioisomer on dehydrogenation under mild condition using active MnO2 gave corresponding 4(3H)-quinazolones 7 and 8, respectively.