953770-85-9

74537-49-8

220000-87-3

953770-85-9

Step 3. Preparation of N-methyl-4-((2-(methylthio)benzo[d]thiazol-6-yl)oxy)pyridine-2-carboxamide: To a solution of 2-(methylthio)benzo[d]thiazol-6-ol (3.76 g, 19.08 mmol, 1.0 eq.) in DMF (25 mL), Cs2CO3 (15.54 g, 47.70 mmol, 2.5 equivalent) and stirred at room temperature. Subsequently, 4-chloro-N-methylpyridinecarboxamide (4.86 g, 28.62 mmol, 1.5 eq.) was added to the reaction mixture and the mixture was stirred at reflux at 70 °C overnight. After completion of the reaction, the mixture was cooled in an ice bath, water (100 mL) was added and the aqueous layer was extracted with ethyl acetate (3 x 150 mL). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by an ISCO silica gel column (20 g) with an elution gradient of 0%-50%-80%-100% ethyl acetate-hexane mixture at a flow rate of 40 mL/min over 45 min to afford N-methyl-4-((2-(methylthio)benzo[d]thiazol-6-yl)oxy)pyridine-2-carboxamide (3.88 g, 62% yield) as a white solid. Mass spectrometry detected [M+H]+=332.1.