反应详情

4.55 g of manganese dioxide (88%, 46 mmol) was added to a solution having 2.21 g (5.1 mmol) of (2,3,4-trimethoxy-6-methylphenyl)(5-bromo-4-chloro-2-methoxy-3-pyridyl)methanol dissolved in 70 ml of toluene, followed by reflux with heating for 1 hour. 4.55 g of manganese dioxide (88%, 46 mmol) was further added, followed by reflux with heating for 1 hours. The reaction mixture was cooled to room temperature, manganese dioxide was removed by filtration on the pad of celite, and toluene was distilled off under reduced pressure. The obtained crude product was purified by silica gel chromatography to obtain 1.90 g (yield: 87%) of 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5-bromo-4-chloro-2-methoxypyridine (melting point 84 to 87° C.).

1. temperatureby reflux
2. temperaturewith heating for 1 hour
3. temperatureby reflux
4. temperaturewith heating for 1 hours
5. custommanganese dioxide was removed by filtration on the pad of celite, and toluene
6. distillationwas distilled off under reduced pressure
7. customThe obtained crude product
8. customwas purified by silica gel chromatography