反应详情

A suspension of 5-amino-6-fluoro-2(3H)-benzothiazolone (12.98 g) in conc. hydrochloric acid (70 g) was cooled to 0° to 5° C., and a saturated aqueous solution of sodium nitrite (5.08 g) was dropwise added thereto at 0° to 5° C., followed by stirring at the same temperature for 30 minutes. The resultant mixture was cooled to -20° C., and a solution of stannous chloride (28.06 g) in conc. hydrochloric acid (30 g) was added thereto all at once, followed by stirring at 0° C. for 2 hours. The reaction mixture was neutralized with potassium hydroxide, a colloidal substance originated from stannous chloride was removed by celite and the resultant solution was extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and concentrated to give 6-fluoro-2(3H)-benzothiazolon-5-ylhydrazine (6.60 g).

1. temperaturewas cooled to 0° to 5° C.
2. customat 0° to 5° C.
3. stirringby stirring at 0° C. for 2 hours
4. customwas removed by celite
5. extractionthe resultant solution was extracted with ethyl acetate
6. washThe extract was washed with water
7. dry with materialdried over magnesium sulfate
8. concentrationconcentrated