PURPOSE: To purify the titled compound useful as a coronary vasodilator in high purify, by washing a solution of crude 5-methyl-7-diethylamino-s-triazolo[1,5-a] pyrimidine in a hydrocarbon with water at a specific temperature.
CONSTITUTION: A solution of crude 5-methyl-7-diethylamino-s-trizolo[1,5-a]pyrimidine (general name: trapidil) in a hydrocarbon, e.g. n-hexane, is washed with water at 40W80°C, and the above-mentioned trapidil is then recovered from the hydrocarbon solution. It is important to prepare the solution in about 50W500g/ lconcentration in the hydrocarbon solvent in order to wash the crude trapidil. The purification effect is little simply by washing the solution with water in comparison with the great loss in the water. According to the method, not only colored impurities can be removed efficiently but also the trapidil can be recovered in high yield.
SHIMOSUGA YASUHISA
MOTOYAMA YOSHIO
