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

Participants

Reaction Conditions

Reaction Steps

A stirred solution of triphenylphosphine (8.57 g, 32.6 mmol) in anhydrous methylene chloride (110 mL) under nitrogen at 0° C. was treated with N-bromosuccinimide (5.80 g, 32.6 mmol). After 15 min, 2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-propionic acid (prepared as in Example 1, 9.00 g, 27.2 mmol) was added to the reaction. The mixture was allowed to warm to 25° C. After stirring at 25° C. for 10 min, the reaction was treated with 2-amino-5-bromopyrazine (7.92 g, 45.6 mmol) followed by pyridine (8.79 mL, 108.8 mmol). The mixture was allowed to stir at 25° C. for 1.5 h. At this time, the reaction was diluted with methylene chloride and then was washed with a 1N aqueous hydrochloric acid solution (200 mL) followed by a 10% aqueous potassium carbonate solution (100 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 70–230 mesh, 3/7 ethyl acetate/hexanes) afforded N-(5-bromo-pyrazin-2-yl)-2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-propionamide (10.02 g, 76%) as a white foam: mp 77–82° C. (foam to gel); (ES)+-HRMS m/e calcd for C19H21BrClN3O3S (M+H)+ 486.0249, found 486.0255.

Provenance & Evidence