The reaction of gamma-chlorobutyrophenone (I) with ethylene glycol (II) by means of p-toluenesulfonic acid in refluxing benzene gives the corresponding ethylene ketal (III), which is condensed with cis-2,6-dimethylpiperidine (IV) by means of Na and heat, and hydrolyzed with concentrated HCl yielding gamma-(cis-2,6-dimethyl-1-piperidyl)butyrophenone (V). Finally, this compound is condensed with 2-bromopyridine (VI) by means of butyllithium in THF.

The reaction of dimethylpiperidine (IV) with 3-bromopropanol (VII) in refluxing xylene gives 1-(3-hydroxypropyl)-2,6-cis-dimethylpiperidine (VIII), which by treatment with SOCl2 in refluxing benzene is converted into 1-(3-chloropropyl)-2,6-cis-dimethylpiperidine (IX). Finally, this compound is condensed with 2-benzoylpyridine (X) by means of Li in THF.

The reaction of gamma-chlorobutyrophenone (I) with ethylene glycol (II) by means of p-toluenesulfonic acid in refluxing benzene gives the corresponding ethylene ketal (III), which is condensed with cis-2,6-dimethylpiperidine (IV) by means of Na and heat, and hydrolyzed with concentrated HCl yielding gamma-(cis-2,6-dimethyl-1-piperidyl)butyrophenone (V). Finally, this compound is condensed with 2-bromopyridine (VI) by means of butyllithium in THF.

The reaction of dimethylpiperidine (IV) with 3-bromopropanol (VII) in refluxing xylene gives 1-(3-hydroxypropyl)-2,6-cis-dimethylpiperidine (VIII), which by treatment with SOCl2 in refluxing benzene is converted into 1-(3-chloropropyl)-2,6-cis-dimethylpiperidine (IX). Finally, this compound is condensed with 2-benzoylpyridine (X) by means of Li in THF.