5198-80-1

5198-86-7

5198-80-1

General procedure for the synthesis of 2-bromo-4-formylthiazole from 2-bromothiazole-4-methanol: 0.22 mol of dimethylsulfoxide was dissolved in 50 mL of dichloromethane and added slowly and dropwise to 200 mL of dichloromethane solution containing 0.11 mol of oxalyl chloride over a temperature range of -75 to -65 °C. The reaction mixture was stirred at this temperature for 30 minutes. Subsequently, 0.1 mol 2-bromothiazole-4-methanol was slowly added dropwise to a 100 mL dichloromethane solution at the same temperature range. After the dropwise addition was completed, the reaction mixture continued to be stirred at -75 to -65°C for 2 hours. Next, 0.5 mol of triethylamine was slowly added dropwise while keeping the temperature constant. The temperature of the reaction mixture was gradually increased to -10 °C and maintained at this temperature for 1 hour. Upon completion of the reaction, the mixture was poured into 400 mL of aqueous solution containing 0.4 mol of sodium bicarbonate and stirred for 30 minutes. The aqueous phase was extracted with dichloromethane, the organic layers were combined and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure and the resulting residue was purified by column chromatography.