Pyridine → 3-cyclopentyl-2(R)-(4-methanesulfonyl-phenyl)-N-(5-methylsulfanyl-pyrazin-2-yl)-propionamide

Participants

Reaction Conditions

Reaction Steps

A solution of 3-cyclopentyl-2(R)-(4-methanesulfonylphenyl)-propionic acid (prepared as in Example 3, 1.21 g, 4.07 mmol) and N,N-dimethylformamide (5 drops) in methylene chloride (10 mL) was cooled to 0° C. The reaction mixture was then treated with oxalyl chloride (0.53 mL, 6.10 mmol), and the resulting reaction mixture was stirred at 0° C. for 1 h. The solution was then concentrated in vacuo, and the orange-brown gel was dissolved in methylene chloride. The resulting solution was added dropwise via an addition funnel at 0° C. to a solution of 5-methylsulfanyl-pyrazin-2-ylamine (prepared as in Example 4, 0.58 g, 4.07 mmol) in methylene chloride (10 mL) and pyridine (0.36 mL, 4.48 mmol). The reaction mixture was stirred at 0° C. for 30 min and then was allowed to warm to 25° C. where it was stirred for 3 h. The reaction mixture was quenched with a 1N aqueous citric acid solution (10 mL) and was stirred for 15 min. The reaction was then diluted with ethyl acetate (75 mL) and a 1N aqueous citric acid solution (50 mL). The layers were separated, and the organic layer was then washed with a saturated aqueous sodium bicarbonate solution (50 mL), water (50 mL), and a saturated aqueous sodium chloride solution (50 mL), dried over magnesium sulfate, filtered, and concentrated in vacuo. Biotage chromatography (FLASH 40M, Silica, 1/1 ethyl acetate/hexanes) afforded 3-cyclopentyl-2(R)-(4-methanesulfonyl-phenyl)-N-(5-methylsulfanyl-pyrazin-2-yl)-propionamide (0.864 g, 51%) as a white foam: mp 71–77° C. (foam to gel); (ES)+-HRMS m/e calcd for C20H25N3O3S2 (M+H)+ 420.1410, found 420.1415.

Provenance & Evidence