A solution containing 4-(tert-Butyl-dimethyl-silanyloxy)-3-({6-[(naphthalene-2-carbonyl)-amino]-5-oxo-1,2,3,5,6,7,10,10a-octahydro-pyrrolo[1,2-a]azocine-3-carbonyl}-amino)-butyric acid benzyl ester (590 mg, 0.86 mmol) in MeOH (10 mL) is treated with 1N NaOH (2.5 mL) and stirred at rt for 12 hrs. The solution was poured into water, acidified to pH=3 with 10% citric acid, and extracted with EtOAc. The combined organic extracts are washed with brine and dried over Na2SO4. The solution is filtered and concentrated to yield 492 mg of desired product that was used without further purification. MS (ESI) 594 (M+1).
