Dimethyl Disulfide → 4-Fluoro-2-methylsulfanyl-benzoic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 2-bromo-4-fluorobenzoic acid (15 g, 68.5 mmol, Marshallton Research Laboratories) in THF (150 mL) under argon at 0° C. was treated with chloro(methyl)magnesium (5.64 g, 75.34 mmol, 2.94 M in THF) over 5 minutes. The temperature during addition was maintained below 10° C. The resulting solution was cooled to −78° C. and n-butyllithium (9.65 g, 150.7 mmol, 2.5M in hexanes) was added over 10 minutes. The reaction was kept below −65° C. during the addition. The reaction was stirred at −78° C. for 50 minutes. A solution of (methyldithio)methane (38.71 g, 410.9 mmol) in THF (20 mL), precooled to −78° C., was added by cannula. The reaction was stirred for 10 minutes, warmed to zero ° C. and stirred at zero ° C. for 2 hours until a solid began to precipitate. The reaction was allowed to warm to 25° C. and stirred overnight. The reaction was poured into 1N HCl and extracted with EtOAc. The water layer was extracted with EtOAc twice more, the organic layers were combined, dried over Na2SO4, filtered and evaporated. The crude solid was suspended in 5% EtOAc/Hexanes and stirred for an hour, then filtered and dried to give the product as a white solid.

Provenance & Evidence