AlHMS as an efficient catalyst for the synthesis of chromenes derivatives

Catalytic activity of AlHMS was investigated as a cheap heterogeneous reusable catalyst in some multicomponent reactions for the synthesis of various chromenes. Threecomponent reaction of 2hydroxynaphtoquinone 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 fivecomponent reaction of 2,5dihydroxy1,4benzoquinone, two equivalent of an aromatic aldehyde and two equivalent of dimedone or 1,3cyclohexadione with efficient catalytic effect of AlHMS. Threecomponent reaction of an aldehyde, malononitrile and 1naphthole in the presence of AlHMS gave 2amino4phenyl4Hbenzo[h]chromene3carbonitriles in high yields. The workup 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.