An efficient and green method for the synthesis of 1, 4-dihydropyridine derivatives mediated in an ionic liquid, [bmim][BF4], through a four-component condensation process of aldehydes, 1, 3-dione, Meldrum＇s acid and ammonium acetate is disclosed in this paper.
Xin Ying ZHANG Yan Zhen LI Xue Sen FAN Gui Rong QU Xue Yuan HU Jian Ji WANG
The reaction of aromatic aldehydes 1 with 5, 5-dimethyl-1, 3-cyclohexandione 2 was investigated in this paper by using [bmim][BF4] as the reaction medium. It was found that when the reaction was carried out in the presence of catalytic amount of FeCl3·6H2O, xanthenediones 3 was obtained in high yields. On the other hand, when a combination of trimethylchlorosilane (TMSCl) and FeCl3·6H2O was employed as the catalyst, the reaction afforded ring-opening derivatives of xanthenediones 4 with high efficiency.
