Microwave Assisted Facile Synthesis of Some Novel Mannich's Bases of Isatoic Anhydide Derivatives

An efficient microwave assisted protocol for the synthesis of Mannich's bases of isatoic-anhydride derivatives 4(a-g) has been described. Treatment of isatoic anhydride (1) with formaldehyde yielded 1-hydroxymethyl-1H-benzo[d][1,3]oxazine-2,4-dione (2) followed by reaction with HCl afforded 1-chloromethyl-1H-benzo[d][1,3]oxazine2,4dione (3) which reacted smoothly with sec. amines to give mannich's bases 4(a-g) in excellent yield.