X-ray diffraction studies of 5-functionalized substituted 1,2,3,4-tetrahydropyrimidin-2-ones(thiones): I. Molecular structures of 5-acetyl-4-ethyl-6-methyl-1,2,3,4-tetrahydropyrimidine-2-thione, 5-acetyl-6-methyl-4-(4-methylphenyl)-1,2,3,4-tetrahydropyrimidine-2-thione, and 5-acetyl-4-(4-methoxyphenyl)-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one

The structures of three 5-acetyl-1,2,3,4-tetrahydropyrimidin-2-ones(thiones), namely, 5-acetyl-4-ethyl-6-methyl-1,2,3,4-tetrahydropyrimidine-2-thione, 5-acetyl-6-methyl-4-(4-methylphenyl)-1,2,3,4-tetrahy-dropyrimidine-2-thione, and 5-acetyl-4-(4-methoxyphenyl)-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one, which are potential medicinals, are studied by X-ray diffraction. The conformational features of the molecules studied are analyzed. For these compounds, the dependence of the conformation of the tetrahydropyrimidine ring on the orientation of the substituent at the C(4) atom with respect to the heterocycle is found.