Dicyclohexylcarbodiimide → Nalpha-[N-t-Butoxycarbonyl-3-(2-pyridyl)-D-alanyl]-1,beta-dimethyl-D-tryptophan methyl ester

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Reaction Steps

To a solution of (αR,βR)-1,β-dimethyltryptophan methyl ester (6.36 g) and Nα -t-butoxycarbonyl-3-(2-pyridyl)-D-alanine (6.65 g) in dry methylene chloride (250 ml) was added dicyclohexylcarbodiimide (5.15 g), and resulting mixture was stirred for 1.5 hours at room temperature. After evaporation of the solvent, crude residue was taken up with ethyl acetate (200 ml), filtered, washed with water and saturated sodium bicarbonate solution, dried over magnesium sulfate, treated with active charcoal, and evaporated. Nα -[N-t-Butoxycarbonyl-3-(2-pyridyl)-D-alanyl]-1,β-dimethyl-D-tryptophan methyl ester (10.54 g) was obtained as an oil.

Provenance & Evidence