General procedure for the synthesis of 5-methoxybenzo[d]thiazole from 5-methoxy-2-benzothiazolamine: 5-methoxybenzo[d]thiazol-2-amine (397 mg, 2.2 mmol) was dissolved in tetrahydrofuran (THF, 16 mL). Tert-butyl nitrite (0.375 mL, 3.17 mmol) was slowly added to the solution at 60 °C and the reaction mixture was continuously stirred overnight. Upon completion of the reaction, the solvent was removed by rotary evaporator. The crude product obtained was purified by silica gel column chromatography (SNAP 10 g column, eluent was hexane/ethyl acetate mixed solvent) to finally obtain 5-methoxybenzo[d]thiazole (281 mg, 77.3% yield) as a yellow solid.
