A solution of 1.37 g (19.7 mmol, 1.3 equivalents) of hydroxylamine hydrochloride in 9.2 mL (114 mmol, 7.5 equivalents) of dry pyridine at 0° C. was treated with 5.8 mL (45 mmol, 3.0 equivalents) of trimethylsilyl chloride, causing white solids to precipitate. The mixture was allowed to warm to ambient temperature overnight. This mixture was then cooled to 0° C. and treated with a solution of 7.54 g (15.1 mmol) of 3-{(1-chlorocarbonylcyclopentyl)-[4-(4-fluorophenoxy)-benzenesulfonyl]amino}propionic acid ethyl ester in 73 mL of dichloromethane, prepared as described above, without isolation, causing an exotherm to about 8° C. This mixture was stirred at 0° C. for 30 minutes and at ambient temperature for about one hour. The reaction was then treated with 50 mL of 2N aqueous hydrochloric acid and was stirred at ambient temperature for one hour. The aqueous phase was extracted with dichloromethane and the combined organic phases were washed with 2N aqueous hydrochloric acid (2×50 mL) and water (50 mL). This solution of 3-[[4-(4-fluorophenoxy)benzenesulfonyl]-(1-hydroxycarbamoylcyclopentyl)amino]propionic acid ethyl ester in dichloromethane was used for the preparation of 3-[[4-(4-fluorophenoxy)benzenesulfonyl]-(1 -hydroxycarbamoylcyclopentyl)amino]propionic acid without isolation. An aliquot was concentrated to a foam.
