Diisopropylethylamine → L-Phenylalanine, methyl ester

Participants

Reaction Steps

A solution of 4-[[(2,6-dichlorophenyl)carbonyl]amino]-L-phenylalanine methyl ester hydrochloride (1.23 g, 3.05 mmol), 2-chloro-6-methylbenzoic acid (0.50 g, 2.93 mmol), HBTU (1.16 g, 3.05 mmol) and DIPEA (1.33 mL, 7.6 mmol) in DMF (12 mL) was stirred 15 hr at room temperature. The mixture was diluted with ethyl acetate (250 mL) and was washed with 0.5 N HCl (2×80 mL), sat. sodium bicarbonate (2×80 mL) and brine (2×80 mL) and was dried (Na2SO4). The solution was filtered and concentrated to a yellow gum which was crystallized from ethyl acetate-hexane to give N-(2-chloro-6-methylbenzoyl)-4-[(2,6-dichlorophenyl)carbonyl]amino]-L-phenylalanine methyl ester (0.75 g), suitable for use in the next step. The mother liquors were concentrated and purified by silica gel chromatography eluting with 1:1 ethyl acetate:hexane to give an additional 0.625 g.

Provenance & Evidence