Three-Component One-Pot Condensation of 2-Hydroxy-1,4-Naphthoquinone with Aromatic Aldehydes and Methyl Carbamate: Synthesis of 4-aryl-3,4-Dihydronaphtho[3,4- e ][1,3]Oxazine-2,5,10-Trione in Aqueous Media

Abstract

A green and efficient method for oxazine ring formation is established using the reaction of 2-hydroxy-1,4-naphthoquinone and aromatic aldehydes with methyl carbamate catalysed by p-toluenesulfonic acid in aqueous media to afford 4-aryl-3,4-dihydronaphtho[3,4-e][1,3] oxazine-2,5,10-triones in excellent yields. The salient features of this protocol are short reaction times and high yields while avoiding any hazardous organic solvent. Therefore, this procedure could be classified as green chemistry.