2-(Aminoaryl)alkanone O-phenyl oximes: versatile reagents for syntheses of quinazolines

摘要

Microwave irradiations of 2-(aminoaryl)alkanone O-phenyl oximes and carbonyl compounds generate iminyl radicals in company with imines; iminyl on inline ring closure yields dihydroquinazolines or quinazolines when ZnCl_2 is included in the mixture. The quinazoline ring is an important structural motif in many biologically active compounds. Interest in new ways of making derivatives is high because anticancer, antibacterial, antic-onvulsant and diuretic activities have been reported for various quinazoline alkaloids. For example, 2-substituted-4-aminoquinazolines are known to be potent against several bacterial strains. l,2-Dihydro-4-aminoquinazoline derivatives are effective and selective inhibitors of inducible nitric oxide synthase and show anti-inflammatory activity in vivo.4 With the exception of the CuCl_2 catalysed reaction of aldehydes with anthranilamide, methods of forming the quinazoline ring either require multi-step preparations of special re-agents/reactants or give moderate yields.