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 threecomponent 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.
Key words: Dihydropyrimidine, l-proline nitrate, ionic liquids, one-pot multicomponent reaction, catalyst.
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