4-Methylmorpholine → N-[N-Phthalimido-3-(3-thienyl)-L-alanyl]-6-hydroxy-L-norleucine, methyl ester

Participants

Reaction Conditions

Reaction Steps

N-Methylmorpholine (1.89 ml., 18.12 mmol.) was added to a solution of 6-hydroxy-L-norleucine, methyl ester, hydrochloride (10.66 mmol.) in methylene chloride (41 ml.)/dimethylformamide (11 ml.) at room temperature under argon. The resulting mixture was cooled to 0° C. and N-phthalimido-3-(3-thienyl)-L-alanine (3.21 g., 10.66 mmol.), hydroxy-benzotriazole (1.48 g., 10.98 mmol.), and 1-ethyl-3-(3dimethylaminopropyl)carbodiimide (2.25 g., 11.73 mmol.) were added sequentially. After stirring at 0° C. for 30 minutes, the mixture was warmed to room temperature and stirred for 2 hours. The volatiles were evaporated and the residue was partitioned between ethyl acetate and water. The organic layer was washed successively with 0.5 N hydrochloric acid, water, saturated sodium bicarbonate, and brine, and the organic layer was dried (sodium sulfate), filtered, and concentrated. The residue was flash chromatographed (Merck silica gel) eluting with 4:1 ethyl acetate/hexane to give 3.8 g. of title compound as a white foam. TLC (ethyl acetate) Rf =0.56.

Provenance & Evidence