An efficient and green synthesis of 1,4-dihydropyridine derivatives through multi-component reaction in ionic liquid

Through multi-component condensation of aldehydes, 1,3-dione, Meldrum's acid, acid ammonium acetate in an ionic liquid ([bmim][BF4]), a series of 1,4-dihydropyridine derivatives were prepared in excellent yields in the absence of any additional catalysts. In addition, [bmim][BF4] can be recovered and reused effectively for at least six times without obvious decrease of its efficiency. Advantages of this novel protocol include simple operational process, environmental benignancy, and high efficiency. (c) 2006 Wiley Periodicals, Inc.