To a solution of 1-{[(α-benzoylbenzyloxy)carbonyl]aminomethyl}-1-cyclohexane acetic acid (61) (1.89 g, 4.6 mmol) in 40 mL of CH2Cl2 was added 77% mCPBA (2.07 g, 9.2 mmol) and NaHCO3 (0.78 g, 9.2 mmol), respectively, at room temperature and the resulting mixture was stirred at room temperature overnight. The reaction mixture was acidified with 10% citric acid and extracted with CH2Cl2. The organic extract was washed with brine and dried over Na2SO4. After removing the solvent under reduced pressure, the residue was purified by reverse phase preparative HPLC (acetonitrile-water, 0.1% formic acid) to afford 960 mg (49%) of the title compound (59). 1H NMR (CDCl3, 400 MHz): δ 1.58-1.35 (m, 10H), 2.34 (s, 2H), 3.26 (dd, J=6.8, 0.8 Hz, 2H), 5.38 (t, J=6.8 Hz, 1H), 7.46-7.26 (m, 5H), 7.63-7.55 (m, 3H), 7.89 (s, 1H), 8.08 (dd, J=8.8, 1.2 Hz, 2H).
