Synthesis and characterization of dihydropyrimidine derivatives

Abstract

4,4,6-Trisubstituted-1,2,3,4,-tetrahydropyrimidin-2-thione derivatives were smoothly synthesized by the reaction of thiourea with α,β-unsaturated ketones in good yields under the mild conditions. The 2-thiotetrahydropyrimidines were S-methylated by methyl iodide in tetrahydrofuran to the corresponding 2-methylthio-3,4-dihydropyrimidine hydroiodides which were easily freed by alkyl amines. In order to compare the structure of the compound which was postulated to be 3,4,4,6-tetramethyl-2-amino-3,4-dihydropyrimidine, synthesized from methylguanidine and mesityl oxide, 4,4,6-trimethyl-2-methylthio-3,4-dihydropyrimidine hydroiodide was reacted with methylamine in pyridine. 2-Methylthio group was smoothly substituted by methylamine to 4,4,6-trimethyl-2-methylamino-3,4-dihydropyrimidine hydroiodide, which was identical with hydroiodide salt of the compound postulated previously to be 3,4,4,6-tetramethyl-2-amino 3,4-dihydropyrimidine. The biological activities of the compounds synthesized are being tested.