Phosphorus oxide (P4O10) → 2,5-Difluoro-2',6-dimethyl-4',5',6'-trimethoxybenzophenone

Participants

Reaction Steps

9.3 g (54.3 mmol) of 3,6-difluoro-2-methylbenzoic acid and 9.88 g (54.3 mmol) of 3,4,5-trimethoxytoluene were introduced into 250 ml of absolute dichloromethane, and 54 g (380 mmol) of pulverulent phosphorus pentoxide were then added. The mixture was stirred for 16 hours at room temperature. According to HPLC check, the trimethoxytoluene had not been reacted completely. A further 13.5 g of phosphorus pentoxide were added. After a further four hours, the reaction mixture was poured into water and extracted with dichloromethane. The combined organic phases were then dried and concentrated. The crude product was purified by reversed-phase MPLC (eluent acetonitrile/water 7:3). This gave 12.2 g of the compound I.5-02 (36 mmol, 67% yield).

Provenance & Evidence