反应详情

20.0 g (230 mmol) of manganese dioxide was added to a solution having 4.80 g (10.3 mmol) of (2,3,4-trimethoxy-6-methylphenyl)(5-bromo-4-trifluoromethyl-2-methoxy-3-pyridyl)methanol obtained in Step (c) dissolved in 110 ml of toluene, followed by stirring under reflux with heating for 1 hour. After cooling to room temperature, the mixture was subjected to filtration on the pad of celite and the solvent was distilled off under reduced pressure. The crude product was purified by silica gel column chromatography to obtain 3.93 g (yield: 82%) of 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5-bromo-4-trifluoromethyl-2-methoxypyridine (Compound No. 31).

1. temperatureunder reflux
2. temperaturewith heating for 1 hour
3. filtrationthe mixture was subjected to filtration on the pad of celite
4. distillationthe solvent was distilled off under reduced pressure
5. customThe crude product was purified by silica gel column chromatography