Methyl iodide → 5-Methoxy-2-(methylsulfanyl)-1,3-benzothiazole

Participants

Reaction Steps

5-Methoxy-2-mercaptobenzothiazole (18.3 g, 0.1 mol) was dispersed in 125 ml 95% ethanol. Addition of 10.1 g (0.1 mol) triethylamine gave a brown solution. Addition of iodomethane (14.2 g, 0.1 mol) was slightly exothermic. Additional heating brought the mixture to reflux for 2 hours. After cooling, the residue was dispersed in isopropanol and filtered to remove triethylammonium iodide. The filtrate was mixed with water and the layers separated. The aqueous phase was extracted 3×50 ml methylene chloride. The organic portions were combined, washed and brine, and dried with Na2SO4. Filtration and rotary evaporation yielded 21.85 g brown liquid which was distilled at 158°-162° C. (0.125 mm) to give 16.73 g (85%).

Provenance & Evidence