N-Sulfonic acid poly(4-vinylpyridinium) chloride as a highly efficient and reusable catalyst for the Biginelli reaction

摘要

A mild, simple and efficient procedure for the preparation of 3,4-dihydropyrimidin-2(1H)-ones and-thiones is described using N-sulfonic acid poly(4-vinylpyridinium) chloride(NSPVPC) as a heterogeneous and efficient catalyst under solvent-free conditions. Simple methodologies, easy work-up procedure, easy preparation of the catalyst, excellent yields and very short reaction times are among the other advantages of this work. Further, the catalyst can be reused and recovered for several times without significant decrease in its activity.