One-pot Synthesis of 2-Amino-4H-chromenes Derivatives in Aqueous Solution of Choline Hydroxide

2-Amino-4H-chromenes have showed broad bioactivities and attracted great attention in synthetic chemistry. Here, the aqueous solution of choline hydroxide was found to be an efficient catalytic system for the one-pot synthesis of 2-amino-4H-chromenes under room temperature. Various aldehydes, malononitrile and phenols could be converted to the corresponding 2-amino-4H-chromenes smoothly with good to excellent isolated yields. This catalytic system had high chemo-selectivity with biocompatible catalyst in green solvents, water. Its operation and work-up procedures were very simple, and importantly, the target compounds could be obtained from simple centrifugation and washing procedures, no column purification was needed. In addition, the catalytic system involving choline hydroxide and water could be easily reused for at least five cycles with high activity. The above advantages made this catalytic system promising in the industrial production of 2-amino-4H-chromenes.