p-Toluenesulfonic acid monohydrate → N-(5-acetyl-pyrazin-2-yl)-2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-propionamide

Participants

Reaction Conditions

Reaction Steps

A solution of 2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-N-[5-(1,1-dimethoxy-ethyl)-pyrazin-2-yl]-propionamide (1.22 g, 2.459 mmol) in acetone (28 mL) and water (3 mL) was treated with p-toluenesulfonic acid monohydrate (142.5 mg, 0.738 mmol). The reaction mixture was heated to 60° C. for 30 min and then was diluted with ethyl acetate (100 mL). The organic layer was washed with a saturated aqueous sodium bicarbonate solution (100 mL), water (100 mL), and a saturated aqueous sodium chloride solution (100 mL), dried over magnesium sulfate, filtered, and concentrated in vacuo. Biotage chromatography (FLASH 40M, Silica, 1/3 ethyl acetate/hexanes) afforded the N-(5-acetyl-pyrazin-2-yl)-2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-propionamide as a white foam (1.07 g, 96%): mp 77–80° C. (foam to gel); (ES)+-HRMS m/e calcd for C21H24ClN3O4S (M+H)+ 450.1249, found 450.1253.

Provenance & Evidence