124.8 mg (0.238 mmol) of methyl 4-{[{2-[(2-chlorobenzyl)-oxy]phenethyl}(5-methoxy-5-oxopentyl)amino]methyl}benzoate from Ex. 1 are initially charged in 0.3 ml of methanol and 0.17 ml of water and admixed with 0.2 ml of a 40% strength sodium hydroxide solution. The mixture is stirred at 60° C. for one hour and then cooled, and the methanol is distilled off under reduced pressure. The aqueous phase is adjusted to pH 4 by addition of a citric acid/aqueous sodium hydroxide solution buffer and the resulting precipitate is separated off. Tituration with boiling cyclohexane gives a finely crystalline product.
