反应详情

A mixture of intermediate 23 (1.33 g, 6.9 mmol), boric acid (2.3 g, 37.2 mmol) and formic acid (17 mL) was heated to reflux and stirred for 6 h. The reaction mixture was cooled to rt and diluted with water. The solution was made alkaline and extracted with ethyl acetate. Further purification by column chromatography (elution with PE/EtOAc=3:1) gave 5-methoxybenzo[d]thiazole (intermediate 24) (290 mg, 15%). HPLC: 99%, RI 2.646 min. MS (ESI) m/z 166.0 [M+H]+.

1. temperaturewas heated
2. temperatureto reflux
3. extractionextracted with ethyl acetate
4. customFurther purification
5. washby column chromatography (elution with PE/EtOAc=3:1)