1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → (2S,4R)-{[1-(Naphthalene-2-sulfonyl)-4-tritylsulfanyl-pyrrolidine-2-carbonyl]-phenethyl-amino]-acetic acid tert-butyl ester

Participants

Reaction Steps

A solution of 800 mg (1.38 mmol) (2S,4R)-1-(Naphthalene-2-sulfonyl)-4-tritylsulfanyl-pyrrolidine-2-carboxylic acid and 390 mg (1.66 mmol) crude phenethylamino-acetic acid tert-butyl ester in 14 ml THF was cooled to 0° C. and treated with 318 mg (1.66 mmol) EDCI and 19 mg (0.14 mmol) HOBT. The reaction was warmed up to RT over night and partitioned between aqueous 10% KHSO4/ethyl acetate (3×). The organic phases were washed with aqueous saturated NaHCO3 solution and dried over Na2SO4. Purification by flash-chromatography on silicagel (Hexane/EtOAc 4:1 to 1:1) gave 290 mg (26%) (2S,4R)-{[1-(Naphthalene-2-sulfonyl)-4-tritylsulfanyl-pyrrolidine-2-carbonyl]-phenethyl-amino}-acetic acid tert-butyl ester, MS: 797 (MH+)

Provenance & Evidence