3-Bromo-4-methylpyridine

• substituted 4-(2,2-diphenylethyl)pyridine-N-oxides for use as potent phosphodiesterase type 4 (PDE4) inhibitors
• benzodiazepine site ligands bearing tricyclic pyridone moiety for human GABA_A receptor
• a novel isomer of ascididemin
• 3-bromopyridine-4-carbonitrile

108-89-4

3430-22-6

The general procedure for the synthesis of 4-methyl-3-bromopyridine from 4-methylpyridine was as follows: 0.054 mol of 4-methylpyridine was added to a 60 mL constant pressure dropping funnel. Under nitrogen protection and stirring conditions at room temperature, it was slowly added dropwise to a mixture consisting of 0.07 mol AlCl3 and 0.01 mol potassium bromide, and the reaction mixture was stirred for 1 hour. A condensing unit was installed, heated to 120°C, and 0.07 mol of bromine was added slowly dropwise for about 1 hour dropwise. Heating and stirring were continued at 120°C for 26 hours. Upon completion of the reaction, the reaction solution was cooled to room temperature and slowly poured into crushed ice with stirring. The pH was adjusted to neutral by the addition of sodium hydroxide solution and stirred until completely dissolved. The aqueous layer was extracted with dichloromethane, the organic layers were combined and the solvent was recovered by steam distillation. The resulting oily product was purified by column chromatography (eluent ratio of VP petroleum ether: ethyl acetate = 6:1) to give 5.3 g of 3-bromo-4-methylpyridine in the form of a tan oil with a purity of 99.9% and a yield of 57%.