The intermediate piperidine (IV) was prepared by bis-alkylation of o-methylphenylacetonitrile (I) with N-Boc-bis(2-chloroethyl)amine (II), followed by deprotection of the resulting N-Boc-piperidine (III) with HCl in EtOAc.

Di-tolylacetic acid (V) was converted into the benzyl ester (VI) using benzyl bromide and K2CO3 in DMF. Subsequent alpha-alkylation of ester (VI) with ethyl bromoacetate provided diester (VII). The benzyl ester group of (VII) was then removed by hydrogenolysis over Pd/C. Condensation of the resulting mono-acid (VIII) with 3-bromopropylamine (IX) in the presence of EDC and HOBt furnished the N-(bromopropyl)succinimide (X). This was finally condensed with piperidine (IV) to provide the title compound.

The intermediate piperidine (IV) was prepared by bis-alkylation of o-methylphenylacetonitrile (I) with N-Boc-bis(2-chloroethyl)amine (II), followed by deprotection of the resulting N-Boc-piperidine (III) with HCl in EtOAc.

Di-tolylacetic acid (V) was converted into the benzyl ester (VI) using benzyl bromide and K2CO3 in DMF. Subsequent alpha-alkylation of ester (VI) with ethyl bromoacetate provided diester (VII). The benzyl ester group of (VII) was then removed by hydrogenolysis over Pd/C. Condensation of the resulting mono-acid (VIII) with 3-bromopropylamine (IX) in the presence of EDC and HOBt furnished the N-(bromopropyl)succinimide (X). This was finally condensed with piperidine (IV) to provide the title compound.