p-Sulfonic acid calixarenes as efficient and reusable organocatalysts for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/-thiones
作者:Daniel L. da Silva、Sergio A. Fernandes、Adão A. Sabino、Ângelo de Fátima
DOI:10.1016/j.tetlet.2011.08.175
日期:2011.11
A new and efficient methodology is proposed for obtaining 3,4-dihydropyrimidin-2(1H)-ones/-thiones through Biginelli reactions. It is based on the use of less than the stoichiometric amount of p-sulfonic acid calixarenes as organocatalysts. A number of aromatic aldehydes as well as urea or thiourea can be employed for successfully synthesizing the corresponding Biginelli adducts. The described methodology