(S)-2-[4-({[2-(1-Isobutoxy-ethoxycarbamoyl)-benzo[b]thiophen-6-ylmethyl]-amino}-methyl)-benzylamino]-3-phenyl-propionic acid cyclopentyl ester (40 mg, 0.06 mmol) was dissolved in THF (2 mL) and water (2 mL). LiOH (8 mg, 0.30 mmol) was added and the reaction mixture heated to 50° C. for 36 h. THF was removed by evaporation and the residue partitioned between water (10 mL) and EtOAc (10 mL). The aqueous layer was isolated and the pH adjusted to 3 by addition of 1M HCl. This was extracted with EtOAc (3×20 mL), the organic layers combined and evaporated to dryness.
