A mixture of 3.00 g (0.0058 mole) of N-[4-[4-(2,4-diamino-6-methyl-5-pyrimidinyl)-1-piperazinyl]-benzoyl]-L-glutamic acid diethyl ester and 12.5 ml of 1N aqueous sodium hydroxide solution in 150 ml of methanol was stirred at room temperature for four hours. The methanol was removed under vacuum at 23° C. and the residue was dissolved in 100 ml of ice water and then neutralized by the addition of 2.5 g (0.0129 moles) of citric acid. The solid precipitate was collected, washed with water, and then triturated several times with ethanol. The remaining solid was dried overnight in vacuo at 67° C. to give 0.75 g of the product as a white powder, mp 270° C. (dec.).
