To 4-[2-(2,2,2-trifluoroethyl)guanidino]-2-[5-(2-benzyloxycarbonylaminoacetylamino)pentyl]pyrimidine (0.2 g.) was added 13 ml. of a solution of potassium hydroxide (0.096 g.) in EtOH (50 ml.), and the mixture was heated under reflux for 35 minutes. The mixture was evaporated in vacuo, a few drops of aqueous HOAc was added to the residue, followed by sodium bicarbonate solution until pH 7 was obtained. The mixture was extracted with EtOAc, the extract dried and evaporated to give a pale yellow solid. This was dissolved in a small volume of hot EtOH and a solution of maleic acid (0.05 g.) in EtOH (0.5 ml.) added. There was obtained 2,4-dihydroxy-3-(5-[4-(2-[2,2,2-trifluoroethyl]guanidino)pyrimid-2-yl]pentyl)imidazole maleate (0.13 g.), m.p. 172°-174°.
