AlHMS as an efficient catalyst for the synthesis of chromenes derivatives

Abstract

Catalytic activity of AlHMS was investigated as a cheap heterogeneous reusable catalyst in some multi-component reactions for the synthesis of various chromenes. Three-component reaction of 2-hydroxy-naphtoquinone with an aromatic aldehyde and dimedone or barbituric acid in H2O under reflux conditions was performed using AlHMS in relatively good yields. The approach was more extended using psuedo five-component reaction of 2,5-dihydroxy-1,4-benzoquinone, two equivalent of an aromatic aldehyde and two equivalent of dimedone or 1,3-cyclohexadione with efficient catalytic effect of AlHMS. Three-component reaction of an aldehyde, malononitrile and 1-naphthole in the presence of AlHMS gave 2-amino-4-phenyl-4H-benzo[h]chromene-3-carbonitriles in high yields. The work-up procedures are very simple, and the products do not require further purification. The catalysts can be recycled and reused for several times without observable loss of performance.