To a solution of 1.22 g (3.0 mmol) of 3-benzyloxycarbonylamino-3-methyl-N-[2,3,4,5-tetrahydro-2-oxo-1H-1-benzazepin-3(R)-yl]-butanamide (Example 1, Step F) in 10 mL of dry dimethylformamide under nitrogen was added 131.6 mg (3.29 mmol) of 60% sodium hydride in oil. After stirring for 20 minutes, a solution of 1.14 g (3.29 mmol) of t-butyl 4'-bromomethyl-1,1'-biphenyl-2-carboxylate (prepared according to the procedure of D. J. Carini, et. al. EPO publication 324,377) in 2.5 mL of dimethylformamide was added by cannula. The flask which originally contained the bromide was rinsed with 2.5 mL dimethylformamide which was added to the reaction mixture. After stirring at room temperature for 2 hours, the reaction was diluted with 400 mL of ethyl acetate, washed with 100 mL of water and 100 mL of brine. The organic layer was dried over magnesium sulfate, filtered and the solvent removed under vacuum. The residue was purified by flash chromatography on silica gel eluting with ethyl acetate/hexane (55:45) to afford 1.74 g (96%) of the product as a white foam. 1H NMR (200MHz, CDCl3): 1.15 (s,9H), 1.45 (s,3H), 1.48 (s,3H), 1.76 (m,1H), 2.35-2.62 (m,5H), 4.48 (m,1H), 4.79 (d,14 Hz,1H), 5.04 (t,12 Hz,2H), 5.35 (d,14 Hz,1H), 6.70 (d,6 Hz,1H), 7.10-7.45 (m,17H), 7.72 (m,1H). FAB-MS: calculated for C41H45N3O6 675; found 683 (M+Li).
