SYNTHESIS OF THIAZOLE-FUSED TRICYCLIC QUINAZOLINONE ALKALOIDS AND THEIR DERIVATIVES

Synthesis of thiazole-fused derivatives of tricyclic quinazolinones hitherto undescribed was successfully achieved by replacing anthranilic acid or its derivatives by isomeric polyfunctionalized benzothiazole analogues of anthranilic methyl esters. Some of the new heterocyclic systems are inspired by natural alkaloids such as mackinazolinone, deoxyvasicinone and isaindigotone, showing interesting biological properties. The microwave-assisted method developed is a variant of the Niementowski reaction and was also applied to the synthesis of ring-extended rutaecarpine derivatives.