1,2-Dichloroethane → 3-Hydroxy-4-{2-[(morpholine-4-carbonyl)-amino]-3-phenylmethanesulfonyl-propionylamino}-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

2-[(Morpholine-4-carbonyl)-amino]-3-phenylmethanesulfonyl-propionic acid (1 g, 2.8 mmol), 3-amino-4-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester (700 mg, 3.46 mmol) prepared as in Reference 1, EDC (1.5 g, 7.8 mmol), and HOBt (1.5 g, 9.6 mmol) were combined. Dichloromethane (10 mL) was added and then 4-methylmorpholine (1.5 mL). The mixture was stirred at ambient temperature for 2 hours. After dilution with ethyl acetate (200 mL) the solution was washed with saturated aqueous NaHCO3 (100 mL) and brine (100 mL), dried with MgSO4 and evaporated under vacuum. 3-Hydroxy-4-{2-[(morpholine-4-carbonyl)-amino]-3-phenylmethanesulfonyl-propionylamino}-pyrrolidine-1-carboxylic acid tert-butyl ester (1.05 g, 1.94 mmol) was obtained as yellowish foam and was dissolved in dichloromethane (6 mL). Trifluoroacetic acid (6 mL) was added and the mixture was stirred at ambient temperature for 1 hour. Evaporation under vacuum gave crude morpholine-4-carboxylic acid [1-(4-hydroxy-pyrrolidin-3-ylcarbamoyl)-2-phenylmethanesulfonyl-ethyl]-amide as TFA salt, which was used without further purification.

Provenance & Evidence