1004-40-6

17356-08-0

105-56-6

1004-40-6

General procedure for the synthesis of 6-amino-2-thiouracil from the compound (CAS: 17356-08-0) and ethyl cyanoacetate: 101.5 g (1.88 mol) of sodium methanol was accurately weighed in a reaction flask containing 3 L of 670 g ethanol at room temperature. Subsequently, 67.3 g (0.88 mol) of thiourea was added and stirred until complete dissolution. The reaction mixture was heated to 55 °C and then 100 g (0.884 mol) of ethyl cyanoacetate was slowly added. The heating was continued to reflux and the reflux reaction was maintained for 4.5 h. The progress of the reaction was monitored by thin layer chromatography (TLC) and after confirming the completion of the reaction, the reaction solution was cooled to 15 °C. The reaction mixture was filtered and the filter cake was washed once with 170 g ethanol. The washed filter cake was transferred to a 3 L reaction flask and appropriate amount of water was added, followed by 1.3 kg of water and stirred until complete dissolution. The pH of the solution was adjusted to 4 by slowly adding acetic acid at 20 °C, at which point a large amount of solid precipitated. The solid product was collected by filtration using a suction filter. The filter cake was dried at 45 °C overnight to give a final product of 115.4 g of 6-amino-2-thiouracil in 91.7% yield.