METHOD OF PRODUCING 6-AMINO-1,2-DIHYDRO-1-OXY-2-IMINO-4-PIPERIDINPYRIMEDINE

6-Amino-1,2-dihydro-1-hydroxy-2-imino-4-piperidinopyrimidine of the formula is prepared by a process in which 2-iminopyrimidine derivatives containing [an] acyl and/or acyloxy group(s), of the formula in which R1 represents a hydrogen atom or a radical of the formula in which formula R denotes an alkyl radical or an aryl radical optionally substituted by a halogen atom, R2 represents a hydroxyl group or a radical of the general formula in which formula R has the above meanings, and X represents a chlorine or bromine atom or an optionally substituted arylsulphonyloxy radical, with the further proviso that, in the case in which R1 represents a hydrogen atom, R2 is different from a hydroxyl group, are reacted with piperidine and the 2-imino-4-piperidinopyrimidine derivatives containing [an] acyl and/or acyloxy group(s) obtained of the formula in which R1 and R2 have the above meanings are hydrolysed. 6-Amino-1,2-dihydro-1-hydroxy-2-imino-4-piperidinopyrimidine has a hypotensive action.