SUBSTITUTED PIPERIDINES

Novel piperidines of the formula wherein R1 is C1-C6 alkyl, R2 is hydrogen, (C1-C12) alkyl, aralkyl or cycloalkyl, R3 is a substituted phenyl radical, an aromatic heterocyclic radical of at least 5 ring atoms and containing not more than 4-hetero atoms the rest being carbon, or the radical R4CO, wherein R4 is a phenyl, biphenyl, halophenyl, dichlorophenyl, phenyltriazolyl, phenylazophenyl, benzyloxy, nitrofuryl, alkoxy or trihalomethyl group, n is 3 or 4 are obtained by reacting a compound of the formula wherein R1, R2 and n are as defined hereinabove with a compound R3Z wherein Z is halogen, OH, O-alkyl, OSO2-alkyl, OSO2-aryl, or an anhydride residue and R3 is as defined above, or by reacting a compound of the formula wherein Y is halogen, OH, OSO2-alkyl or OSO2-aryl with an amine of the formula wherein R1, R2, R3, and n are as defined above, and, if desired, forming a pharmaceutically acceptable acid addition salt thereof. Pharmaceutical compositions containing the above compounds and active in inhibiting the growth of protozoa are administered orally or parenterally.