title: Brønsted base-catalyzed one-pot three-component Biginelli-type reaction: an efficient synthesis of 4,5,6-triaryl-3,4-dihydropyrimidin-2(1H)-one and mechanistic study.
abstract: An efficient one-pot synthesis of 4,5,6-triaryl-3,4-dihydropyrimidin-2(1H)-ones via a three-component Biginelli-type condensation of aldehyde, 2-phenylacetophenone, and urea/thiourea in the presence of a catalytic amount of t-BuOK (20 mol %) is described. The reactions proceeded efficiently at 70 degrees C to afford the desired products in moderate to good yields. Detailed mechanistic study shows that the Biginelli-type reaction using urea and thiourea proceeds through two totally different pathways. Enone 5 and bis-urea 8 were highly suggested as respective reaction intermediates for reactions involving thiourea and urea as substrates.
authors.affiliation: Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
authors.forename: Zhi-Liang
authors.initials: ZL
authors.lastname: Shen
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Xu
authors.forename: Shun-Jun
authors.initials: SJ
authors.lastname: Ji