Triethylamine → 4-[[(R)-2-(3,4-Dichloro-phenylamino)-propionyl]-(2,2-dimethoxy-ethyl)-amino]-butyric acid tert-butyl ester

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Reaction Steps

A solution of 0.99 g (4.00 mmol) of 4-(2,2-dimethoxy-ethylamino)-butyric acid tert-butyl ester (intermediate 30) in 24 ml of DMF was treated with 1.03 ml (4.40 mmol) of (R)-2-(3,4-dichloro-phenylamino)-propionic acid (62% ee) (intermediate 31), 0.48 ml (4.40 mmol) of triethylamine and at 0° C. with 2.28 g (6.00 mmol) of HATU. Over night, the suspension was naturally warmed to RT, poured on aqueous 10% KHSO4 solution and extracted with Et2O (3×). The organic phases were washed with aqueous saturated NaHCO3 and aqueous 10% NaCl, dried (Na2SO4) and evaporated to give after purification with flash chromatography (SiO2, dichloromethane/Et2O 97.5:2.5 to 4:1) 1.37 g (74%) of the titled compound as light yellow viscous oil. MS: 463.17 (MH+, 2Cl).

Provenance & Evidence