2-Phenylpropionic acid → HCID 18611253, compound

Participants

Reaction Steps

Phenylpropionic acid (3 g, 20 m mole) was dissolved in 1,2-dichloroethane (80 ml), and while maintaining the solution at an internal temperature between 5 and 8° C., L-alanyl-L-prolyl-L-proline methyl ester hydrochloride (6.69g), triethyl amine (2.02 g, 20 m mole), 1-hydroxybenzotriazole (0.35 g, 3 m mole), and dicyclohexylcarbod iimide (4.12 g, 20 m mole) were added, and the thus obtained mixture was stirred for 4 hours. After that, it was stirred at room temperature overnight, and the precipitated dicyclohexyl urea crystals and triethyl amine hydrochloride crystals were filtered off and were washed with 1,2-dichloroethane (20 ml). The filtrate and the washing were mixed together, and the obtained mixture was washed with 0.5N hydrochloric acid (50 ml), water (80 ml), 0.5N aqueous sodium hydroxide (60 ml) and water (80 ml) in order, and the 1,2-dichloroethane phase was concentrated under reduced pressure To the obtained syrupy residue, water (50 ml) and 5N aqueous sodium hydroxide (5 ml) were added and the obtained mixture was stirred at room temperature for 2 hours. After completion of the saponification, the precipitated dicyclohexyl urea crystals were filtered off and washed with water (5 ml). The filtrate and the washings were mixed together, and the thus obtained mixture was adjusted to pH 2.5 with 6N hydrochloric acid and was extracted with 1,2-dichloroethane (100 ml). The 1,2-dichloroethane phase was washed with water (30 ml), and the 1,2-dichloroethane was distilled off therefrom under reduced pressure To the concentrated residue, carbon tetrachloride (30 ml) was added, and the obtained solution was concentrated under reduced pressure and ethyl ether (100 ml) was added thereto. The solution was changed slowly to a solid material while stirring. A solid material was obtained by filtration, and dried to obtain N-(3-phenylpropionyl)-L-alanyl-L-prolyl-L-proline (5.8 g).

Provenance & Evidence