6-Amino-1,2-di:hydro-1-hydroxy-2-imino-4-piperidino-pyrimidine - obtd. from e.g. protected 4-halo cpd. by reaction with piperidine then hydrolysis; useful as antihypertensive

摘要

Prodn. of formula (I) comprises reacting the 4-substd. cpd. (II) with piperidine to give acyl (cpd.of) acyloxy cpd. (V) which, opt. after isolation, is hydrolysed. R1 = H or COR; R = 1-6C alkyl or opt. halo-substd. aryl; R2 = OH or O.COR; X = Cl, Br or arylsulphonyloxy (opt. having 1 or more substits.) with provisos. Reaction with piperidine is at 0-100 deg.C, esp. room temp., either in piperidine itself as solvent, or in presence of an additional solvent, esp. EtOH, MeCN and/or CHCl3. If piperidine is used as solvent, hydrolysis occurs rapidly at room temp. so (IV) cannot readily be isolated.