General procedure for the synthesis of 2-methyl-4-bromothiazole from dimethyl sulfite: 2,4-dibromothiazole (2.4 g, 9.8 mmol) was dissolved in anhydrous THF (50 mL), and the resulting solution was stirred at -78 °C under argon protection. Slowly n-butyllithium (4.2 mL, 6 mmol, 2.5 M hexane solution) was added and stirring was continued for 1 hour. Subsequently, a solution of dimethyl sulfate (2.7 mL) in THF (5 mL) was added dropwise. The reaction mixture was stirred at -78 °C for 4 h before slowly warming to room temperature and continuing to stir overnight. Upon completion of the reaction, the reaction mixture was diluted with saturated aqueous sodium bicarbonate solution (50 mL). The aqueous layer was extracted with ether, the organic phases were combined, washed with brine, dried over magnesium sulfate and concentrated by rotary evaporation. Finally, purification by silica gel column chromatography afforded 2-methyl-4-bromothiazole as a yellow oil (0.956 g, 55% yield).
