The ethyl ester of 3-piperidinecarboxylic acid (nipecotic acid) (II) is N-alkylated with 4,4-diphenyl-3-butenyl bromide (I). The ethyl ester of N-(4,4-diphenyl-3-butenyl)nipecotic acid thus obtained is then hydrolyzed with HCl to yield the hydrochloride of the free acid.
The methyl ester of 1,2,5,6-tetrahydro-3-pyridinecarboxylate (guvacine) (II) is N-alkylated with 4,4-diphenyl-3-butenyl bromide (I). The methyl ester of N-(4,4-diphenyl-3-butenyl)guvacine thus obtained is then hydrolvzed with HCl to yield the hydrochloride of the free acid.