LAUSR

Preparation of pharmaceutically active 2-amino-4H-pyran derivatives has been achieved using cheap thiamine hydrochloride as catalyst. A wide range of aromatic aldehydes easily undergo condensation with malononitrile and several kinds of 1,3-cyclohexanedione under mild condition to afford the desired product with good purity in excellent yield. This protocol has various advantages as a simple, clean, and environmentally benign three-component process.