The compounds of formula XXlVa are deacylated to the corresponding mixture of epimeric 4-{3-[3(R)-vinyl(or lower alkyl)-4(S)-piperidyl]-2-hydroxypropyl}quinolines of formula Vla, their antipodes or racemates, utilizing a deacylating agent, for example, alkali metal hydroxide, such as sodium hydroxide or potassium hydroxide a reductive deacylating agent such as lithium aluminium hydride, sodium alu