Microwave-assisted reactions: Three component process for the synthesis of 2-amino-2-chromenes under microwave heating

2-Amino-2-chromenes are class of heterocycles that posses considerable interest as pigments, cosmetics, potential agro-chemicals and being the main constituents of many natural products. Although, they are generally prepared either under conventional heating, benign reagents or very recently, a three component condensation in poly-ethylene glycol–water in the presence of nanosized magnesium oxide, most of these methods require prolonged reaction time, reagents in stoichiometric amounts and generate moderate yields of products. Microwave technique performs a better yield in a short reaction time (85–94%; 5–8 min). Also, three-component one step reaction is of great interest for cost savings from the point of raw materials, energy and time. A combination between both techniques will be attractive for researchers in that field.