Condensation of N-benzyl-4-piperidinone (I) with phenethylamine (II) produced the corresponding imine (III), which was subsequently reduced to amine (IV) using NaBH4. Schweiler-Clarke methylation of the secondary amine (IV) in the presence of formaldehyde and formic acid gave (V). The N-benzyl protecting group of (V) was then removed by catalytic hydrogenation, yielding piperidine (VI). This was finally coupled with 3,5-dimethyl-4-propionamidobenzoic acid (VII) by means of diethyl cyanophosphate to produce the target compound, which was isolated as the hydrochloride salt.