Pd(II)‐Catalyzed Aerobic Alcohol Oxidation for Multicomponent Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones in Water

Abstract

AbstractWe describe a multicomponent reaction between isatoic anhydrides, alkylamines and benzylic alcohols using Pd(II)/TPPMS catalyst with cocatalytic Cu(II) salt in water. This cascade reaction involves the catalytic dehydrogenation of benzyl alcohol to benzaldehyde under aerobic conditions, followed by cyclocondensation with in situ generated 2‐aminobenzamides, allowing rapid access to 2,3‐dihydroquinazolin‐4(1H)‐ones (DHQs). This practical method enables direct access to a series of DHQs without strong bases and hazardous oxidants. Mechanistic studies reveal that the multicomponent reaction is first order with respect to the concentrations of benzyl alcohol and catalysts, and proceeds independently of the concentration of the 2‐aminobenzamide intermediate.