Benzoic Acid → 2-Methylbenzoic acid

Participants

Reaction Steps

2f (4.7 g, 9.3 mmol) and n-propanethiol (5.1 mL, 6 eq) were mixed in dimethylformamide (70 mL), potassium t-butoxide (5.7 g, 5 eq) was added thereto, and the mixture was stirred at 135° C. for 2.5 hours. After cooling, the reaction solution was transferred into a mixture of toluene (200 mL) and distilled water (200 mL), methanesulfonic acid (5 g) was added thereto, and the mixture was then stirred. Thereafter, saturated aqueous sodium bicarbonate was added until the aqueous phase became alkalized. Liquid separation was performed, extraction with toluene (200 mL×3) was performed, and the organic phase was washed with distilled water (200 mL×2). The resultant was dried over magnesium sulfate and concentrated. The resulting crude product was purified by recrystallization from THF. Thus, 3.47 g of a free base substance of the object product was obtained. This product was dissolved in ethyl acetate, a solution of benzoic acid (1 eq) in ethyl acetate was added, and the solvent was removed by distillation. The resultant was suspended in ether and collected by filtration, thereby obtaining the object product 2-benzoate. Also, 3f was used as a starting material instead of 2f to obtain 3. This product was converted to methanesulfonate, and the object product 3-methanesulfonate was obtained.

Provenance & Evidence