N-protection of the NH group of (I) with Boc2O and NaOH in Et2O yields derivative (II), which is then condensed with compound (III) by means of NaH in DMF to provide (IV). N-deprotection of (IV) by treatment with TFA in CH2Cl2 followed by reductocondensation with N-Boc-4-piperidone (V) in CH2Cl2 in the presence of Na(OAc)3BH affords compound (VI), which is oxidized with NaBO3.4H2O to provide (VII). Boc removal of (VII) by treatment with TFA in CH2Cl2, followed by reaction of the resulting secondary amine with sulfonyl chloride (VIII) in CH2Cl2 in the presence of Et3N, affords propylsulfonamide derivative (IX). Finally, treatment of (IX) with ethyleneglycol (X) in toluene in the presence of HC(OEt)3 and p-TsOH furnishes the target compound.