N-substituted ureas and thioureas in Biginelli reaction promoted by chlorotrimethylsilane: Convenient synthesis of N1-alkyl-, N1-aryl-, and N1,N3-dialkyl-3,4-dihydropyrimidin-2(1H)-(thi)ones

摘要

The classical Biginelli reaction has been extended by the use of N-substituted ureas and thioureas. A set of N1-alkyl- N1-aryl-, and N1,N3-dialkyl-3,4-dihydropyrimidin-2(1H)-(thi)iones was readily prepared in excellent yield when chlorotrimethylsilane in N,N-dimethylformamide was used as promoter and water scavenger.