1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → N-[(1,3-Dimethylindole-2-Carbonyl)Valinyl]-3-Amino-4-Hydroxy-5-(2',6'-Dichlorobenzyloxy)Pentanoic Acid, t-Butyl Ester

Participants

Reaction Conditions

Reaction Steps

1-Hydroxybenzotriazole hydrate (153 mg, 1.0 mmol) and EDAC (268 mg, 1.4 mmol) were added to a methylene chloride solution of N-(1,3-dimethylindole-2-carbonyl)valine (288 mg, 1.0 mmol, in 3 mL of methylene chloride). The resultant mixture was stirred for 10 minutes under a nitrogen atmosphere at room temperature. A methylene chloride solution of 3-amino-5-(2',6'-dichlorobenzyloxy)-4-hydroxypentanoic acid, t-butyl ester (364 mg, 1.0 mmol, in 2 mL of methylene chloride) was added to the reaction mixture and the mixture was first stirred for one hour under a nitrogen atmosphere at 0° C., and then for 16 hours at room temperature. The reaction mixture was partitioned between ethyl acetate and 5% KHSO4 solution and the aqueous solution was back-extracted with ethyl acetate. The combined ethyl acetate solutions were washed with 5% KHSO4 solution, saturated sodium bicarbonate solution (2×) and brine, dried over sodium sulfate, and concentrated to give crude product (583 mg). The crude product was subjected to flash chromatography on silica gel with ethyl acetate/hexane (2/3) to give the title product as a white solid (260 mg). TLC: (ethyl acetate/hexanes 1:1): Rf =0.38.

Provenance & Evidence