C([N:8]1[CH2:13][CH2:12][N:11](CC2C=CC=CC=2)[CH2:10][CH:9]1[CH2:21][O:22][C:23]([N:25]1[CH2:29][CH2:28][CH2:27][CH2:26]1)=[O:24])C1C=CC=CC=1.[ClH:30]>C(O)C.[Pd]>[ClH:30].[N:25]1([C:23]([O:22][CH2:21][CH:9]2[CH2:10][NH:11][CH2:12][CH2:13][NH:8]2)=[O:24])[CH2:26][CH2:27][CH2:28][CH2:29]11.48 g (3.7 mmol) of 1,4-dibenzyl-2-(1′-pyrrolidinocarbonyloxymethyl)piperazine are dissolved in 40 ml of absolute ethanol and 1 ml of 12N HCl in a 100 ml ground-necked round-bottomed flask. About 100 mg of palladium (10%) on charcoal are added thereto. The mixture is then placed under a hydrogen atmosphere, vigorously stirred and gentle heating is applied (40° C.). When the initial product has disappeared (the reaction program is monitored by thin-layer chromatography eluted with an MeOH/CH2Cl2 mixture (5/95 v/v), after neutralization of an aliquot with a few grains of NaHCO3), the solution is filtered on paper and the catalyst is rinsed several times with ethanol and water. The solvents are then evaporated off under vacuum. 1.04 g of 2-(1′-pyrrolidinocarbonyloxymethyl)piperazine hydrochloride are thus obtained and used in the following step without further purification. Yield: 98.3%. Rf=0.4 (80/20/2 v/v/v CHCl3/MeOH/NH4OH).
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