Amidation of amino aryl acids with orthoesters in aqueous ammonium hydroxide: A strategy to construct quinazolinones and pyrido[2,3-d]pyrimidinones

A one-pot oxidative cyclization of 2-amino aryl acids with orthoesters to quinazoline-4(3H)-ones and pyrido[2,3-d]pyrimidinones was described in a greener approach using aqueous ammonium hydroxide. The synthetic protocol enables greater selectivity with synthetic utility. A wide range of substrate scope was explored with good to excellent yields. The reaction mechanism involves N-benzylation/alkylation, amidation, and subsequent oxidative annulation.