Application background and overview of 2,6-dibromo-4-methylpyridine
2,6-Dibromo-4-methylpyridine can be used as a pharmaceutical synthesis intermediate, such as the preparation of 2-bromo-6-azinyl-4-methylpyridine.
Application and preparation of 2,6-dibromo-4-methylpyridine
2,6-Dibromo-4-methylpyridine is prepared as follows:
The specific steps are as follows: Combine θ-polycarbonate hydroxy^-methyl^-oxo^^-dihydro-S-pyridinecarbonitrile hydrochloride (D1, 5g, 30.94mmol) and phosphorus oxybromide ( 25g, 87.2mmol) were heated together at 13°C for 6 hours. The mixture was cooled in ice and water was carefully added, then the mixture was basified with 2M sodium hydroxide solution and extracted with dichloromethane. The organic phase was separated and evaporated to give a light brown solid. It was purified by silica gel chromatography (CombiFlashCompanion, Redisep80g silica gel column), eluting with cyclohexane-dichloromethane mixture (100%-70% cyclohexane). Fractions containing the major components were combined and evaporated to give the title compound (1.279 g, 16%) as a colorless solid. LCMS (method A): single peak, Rt = 3.09 mins; m/z. MH+250, 252, 254.
Applications of 2,6-dibromo-4-methylpyridine
2,6-Dibromo-4-methylpyridine can be used to prepare 2-bromo-6-azinyl-4-methylpyridine:
The specific steps are as follows: Dissolve 2,6-dibromo-4-methylpyridine (D2, 1.279g, 5.098mmol) in anhydrous dimethyl sulfoxide (12ml) and stir at room temperature. Hydrazine monohydrate (0.99 ml, 20.39 mmol, 4 eq.) was added slowly, and the mixture was stirred at room temperature for 3 hours and then at 12°C for 18 hours. The mixture was cooled to room temperature and poured into water, and the resulting precipitate was collected by filtration, washed with dimethoxytetrahydrofuran water and dried to give the title compound (881 mg, 85%) as a beige solid. LCMS (Method A): Main peak, Rt=1.60mins; m/z. MH+202, 204.
