To a stirred solution of trans(-)-2-chlorocyclohexyl chloroformate (0.16 g, 0.75 mmol ) in anhydrous THF (5 mL) at room temperature was added dropwise a solution of α-methyl-DL-tryptophylphenethylamide (0.23 g, 0.7 mmol) in THF (5 mL), followed by a solution of triethylamine (0.07 g, 0.7 mmol) in THF (5 mL). The reaction was complete after 30 minutes by thin layer chromatographic analysis. The solvent was removed in vacuo and the residue taken up in ethyl acetate (30 mL) and washed successively with 1M aqueous citric acid (2×20 mL), saturated NaHCO3 solution (2×20 mL), 1M NaOH solution (20 mL) and water (4×20 mL). The organic phase was dried over MgSO4 and filtered. Removal of the solvent by vacuum distillation gave the title compound (0.273 g, 81%), a white solid crystallized from ether-hexane, mp 69°-78° C. (ether-hexane); IR (film) 1709 and 1656 cm-1 ; NMR (CDCl3) δ1.2-1.4 (3H, m), 1.54 (3H, s), 1.6-1.8 (3H, m), 2.03-2.23 (2H, m), 2.63-2.69 (2H, m), 3.2-3.5 (4H, m), 3.72-3.79 (1H, m), 4.67-4.73 (1H, m), 5.23 (1H, br.s), 6.1-6.2 (1H, m), 7.0-7.6 (10H, m), 8.08 (1H, br.s); Anal. (C27H32N3O3Cl), C, H, Cl, N.
