Condensation of ethyl carboxylate (I) with chloromethyl derivative (II) by heating with TEA in DMF affords compound (III), which is hydrolyzed with aqueous HBr to provide piperidine (IV). Compound (IV) is then coupled to bromo derivative (V) by means of Na2CO3 in 2-butanone to give protected (VI), whose Boc group is finally removed by treatment with HCl in refluxing 2-propanol to furnish the desired product.