An Efficient and Facile Synthesis of 5-(Thiophene-2-carbonyl)-6-(trifluoromethyl)-tetrahydro-pyrimidin-2(1H)-one and 6-(Thiophen-2-yl)-4,5-dihydropyrimidin-2(1H)-one from Same Substrates Under Different Conditions

A series of 5-(thiophene-2-carbonyl)-6-(trifluoromethyl)-tetrahydropyrimidin-2(1H)-one and 6-(thiophen-2-yl)-4,5-dihydropyrimidin-2(1H)-one derivatives have been synthesized from the reactions of aromatic aldehydes, 4,4,4-trifluoro-1-(thien-2-yl)butane-1,3-dione and urea under the different conditions with high yields. In this research, it was found that the p-toluenesulfonic acid was an efficient catalyst for obtaining 5-(thiophene-2-carbonyl)-6-(trifluoromethyl)-tetrahydropyrimidin-2(1H)-one derivative. At the same time, solvent-free and NaOH were the preferred conditions for the synthesis of 6-(thiophen-2-yl)-4,5-dihydropyrimidin-2(1H)-one derivative. Moreover, because of short reaction time, excellent yields, simple setup, this research offered an efficient process for preparing these kind compounds.