Sodium Hydroxide → 7-fluoro-6-hydrazino-4-propargyl-2H-1,4-benzoxazin-3-one

Participants

Reaction Steps

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).

Provenance & Evidence