Dimethylformamide → 5-Bromo-2-methylbenzoyl chloride

関与物質

反応手順

5-Bromo-2-methylbenzoic acid (725 mg, 3.37 mmol, 1 eq) was suspended in dry dichloromethane (9.7 mL). Oxalyl chloride (0.32 mL, 3.74 mmol, 1.1 eq) and N,N-dimethylformamide (0.013 mL, 0.17 mmol, 0.05 eq) were then added at room temperature and the mixture was stirred for 6 hours. The solvent was then evaporated to give 5-bromo-2-methylbenzoyl chloride as yellow oil. This crude product was dissolved in dry dichloromethane (19.3 mL), AlCl3 (49.5 mg, 3.71 mmol, 1.1 eq) and 42 (600 mg, 3.37 mmol, 1 eq) were then added at 0° C. (internal temperature). The resultant mixture was stirred at this temperature for 30 minutes and then at room temperature overnight. The reaction mixture was poured into ice and water, the organic layer was separated and the aqueous layer was extracted with dichloromethane. The organic layers were gathered, dried over MgSO4, filtered and concentrated. The residue was taken up with n-hexane to form a precipitate which was collected by filtration, washed with n-hexane and dried to afford compound 43 (69% yield) as yellowish crystals.

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