An ionic liquids catalyst approach for synthesis of pyrimidine derivatives using l-proline nitrate

Dihydropyrimidine is one of the heterocyclic compounds that has important bioactivity and is well known for its application in medicine. This study aims to test the catalytic ability of l-proline nitrate in the ionic liquids phase for the synthesis of pyrimidine derivatives. The pyrimidine derivatives were synthesized through a one-pot three-component reaction and characterized by a melting point apparatus, UV-Vis spectrophotometry, Fourier transform infrared, and chromatography mass spectroscopy. The analysis shows that three pyrimidine derivatives, namely ethyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (compound 1), ethyl 4-(4-hydroxyphenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (compound 2), and ethyl 4-(4-methoxyphenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (compound 3), are presented and identified. The best condition of the reaction was carried out with a methanol solvent with a catalyst concentration of 3% mol with a yield at 86.74%. The catalytic ability of ionic liquids l-proline nitrate as a catalyst is more than 2.5 times efficient than that of noncatalysts.