The reductocondensation of 3-(2-aminophenyl)propionamide (I) with 1-[4-(3-acetamidopropoxy)benzoyl]piperidin-4-one (II) by means of H2 and PtO2 in acetic acid gives 3-[2-[1-[4-(3-acetamidopropoxy)benzoyl]piperidin-4-ylamino]phenyl] propionamide (III), which is finally cyclized in refluxing 5% HCl.