Nanosized magnesium oxide as catalyst for the rapid and green synthesis of substituted 2-amino-2-chromenes

A nanosized magnesium oxide catalyzed three-component condensation reaction of aldehyde, malononitrile, and α-naphthol proceeded rapidly in water–PEG to afford corresponding 2-amino-2-chromenes in high yields at room temperature. The greener protocol was found to be fairly general and the catalyst was reused in subsequent reactions with consistent activity.