2,6-Dichloro-7-methylsulfanyl-3-trifluoromethylquinoxaline (116 mg, 0.37 mmol, prepared similarly as described above from 6-chloro-7-methylsulfanyl-3-trifluoromethyl-1H-quinoxaline-2-one, dimethylaminopyridine and POCl3) and 2-mercapto-5-methyl-1,3,4-thiadiazole (146 mg, 1.1 mmol) was dissolved in DMF (3.3 ml). Potassium carbonate (20 mg) was added and the reaction mixture was stirred at 50° C. for 2 hours. The cooled mixture was partitioned between diethyl ether and water. The organic layer separated, evaporated and the residue recrystallised from ethanol to afford 80 mg (50%) of the title compound as a yellow solid.
