反应详情

A suspension of 6-amino-7-fluoro-4-propargyl-2H-1,4-benzoxazin-3(4H)-one (13.0 g) in conc. hydrochloric acid (70 g) was cooled to 0° to 5° C., and a saturated solution of sodium nitrite (5.1 g) was dropwise added thereto at 0° to 5° C., followed by stirring for 2 hours. The resultant mixture was cooled to -30° C., and a solution of anhydrous stannous chloride (28.1 g) in conc. hydrochloric acid (30 g) was added thereto at once, followed by stirring at 0° to 5° C. for 3 hours. Celite (50 g) was added to the reaction mixture, which was neutralized with 10% aqueous sodium hydroxide solution below 10° C. The resulting mixture was filtered, and the filtrate was extracted with ethyl acetate. The extract was washed with water, dried and concentrated to give 7-fluoro-4-propargyl-2H-1,4-benzoxazin-3(4H)-on-6-ylhydrazine (8.2 g).

1. temperaturewas cooled to 0° to 5° C.
2. customat 0° to 5° C.
3. stirringby stirring at 0° to 5° C. for 3 hours
4. additionCelite (50 g) was added to the reaction mixture, which
5. filtrationThe resulting mixture was filtered
6. extractionthe filtrate was extracted with ethyl acetate
7. washThe extract was washed with water
8. customdried
9. concentrationconcentrated