Ethylmorpholine → N-[N-[N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl]-3-methyl-L-valyl]-3-cyclopentyl-L-alanine benzyl ester

Participants

Reaction Steps

993 mg (2.16 mmol) of N-[N-(tert-butoxycarbonyl)-3-methyl-L-valyl]-3-cyclopentyl-L-alanine benzyl ester and 1.23 g (6.47 mmol) of 4-toluenesulphonic acid hydrate were dissolved in 20 ml of acetonitrile and the solution was stirred at room temperature for 2 hours. The solvent was removed by evaporation and the residue was triturated with diethyl ether and filtered off. The solid obtained was added to a mixture of 602 mg (2.16 mmol) of N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanine, 338 mg (2.21 mmol) of 1-hydroxybenzotriazole, 576 mg (3 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 345 mg (3 mmol) of N-ethylmorpholine in 20 ml of dichloromethane and stirred at room temperature for 18 hours. The solution was extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution, then dried over anhydrous magnesium sulphate and evaporated. Chromatography of the residue on silica gel using ethyl acetate/ petrol (3:7) for the elution gave 990 mg of N-[N-[N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl]-3-methyl-L-valyl]-3-cyclopentyl-L-alanine benzyl ester as a white solid; MS: m/e 622 [M+H].

Provenance & Evidence