N-Substituted Ureas and Thioureas in Biginelli Reaction Promoted by Chlorotrimethylsilane: Convenient Synthesis of <i>N</i>1-Alkyl-, <i>N</i>1-Aryl-, and <i>N</i>1,<i>N</i>3-Dialkyl-3,4-Dihydropyrimidin-2(1<i>H</i>)-(thi)ones
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)ones was readily prepared in excellent yield when chlorotrimethylsilane in N,N-dimethylformamide was used as promoter and water scavenger.
Dowex-promoted general synthesis of N,N′-disubstituted-4-aryl-3,4-dihydropyrimidinones using a solvent-free Biginelli condensation protocol
作者:Kamaljit Singh、Divya Arora、Sukhdeep Singh
DOI:10.1016/j.tetlet.2006.04.061
日期:2006.6
Dowex-50W ion exchange resin-promoted solvent-free heating of an intimate mixture of an aldehyde, an active methylene compound and N,N'-dimethylurea furnished the title compounds in moderate to good yields. (c) 2006 Elsevier Ltd. All rights reserved.