A novel four-step methodology for the synthesis of 5-acyl- and 5-arylsulfonyl-1,2-dihydropyrimidin-2-ones has been developed. The reaction of readily available N-[(1-acetoxy-2,2,2-trichloro)ethyl]ureas with Na-enolates of 1,3-diketones, beta-oxoesters, or alpha-arylsulfonylketones followed by heterocyclization-dehydration of the oxoalkylureas formed gave 5-acyl- or 5-arylsulfonyl-4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones. The latter, in the presence of strong bases, eliminate CHCl3 to give the target compounds. The above methodology was also used in the synthesis of 5-acyl-1,2-dihydropyrimidin-2-imines starting from N-[(1-acetoxy-2,2,2-trichloro)ethyl]-N′-guanidine.
A new approach to 5-functionalized 1,2-dihydropyrimidin-2-ones/imines via base-induced chloroform elimination from 4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones/imines
Published: 14 November 2018 by MDPI AG in The 22nd International Electronic Conference on Synthetic Organic Chemistry session General Organic Synthesis
Keywords: 1,2,3,4-Tetrahydropyrimidin-2-ones/imines; 1,2-Dihydropyrimidin-2-ones/imines; Amidoalkylation; Aromatization