A mixture of 0.51 g (2.2 mmol) of 2-methyl-N-(2,3,4,5-tetrahydro-1-benzoxepin-8-ylmethyl)propan-1-amine, 0.51 g (2.2 mmol) of (±)-4-(tert-butoxycarbonyl)morpholine-2-carboxylic acid (Chem-Impex International), 0.59 g (4.4 mmol) of 1-hydroxybenzotriazole hydrate, 0.84 g (4.4 mmol) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.71 mL (5.1 mmol) of triethylamine in 15 mL in dichloromethane was stirred overnight. The mixture was concentrated under reduced pressure, partitioned between 90 mL of ethyl acetate and 30 mL of saturated sodium bicarbonate, and the layers were separated. The organic layer was washed with 30 mL each of water and brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure to give a yellow oil. Purification by flash chromatography (10-70% ethyl acetate in hexanes) gave 0.84 g (86%) of product as a solid white foam. MS (m+1)=447.4; H NMR (400 MHz, CDCl3) 7.09 (m, 1H), 6.8 (m, 2H), 4.7 (m, 1H), 4.44 (d, 1H, J 17 Hz), 4.2-3.8 (m, 6H), 3.50 (m, 1H), 3.21 (m, 2H), 3.02 (m, 2H), 2.79 (m, 2H), 1.96 (m, 3H), 1.72 (m, 2H), 1.45 (d, 9H, J 13 Hz), 0.85 (m, 6H).
