Hydrogen Peroxide → 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine-5-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A suspension of 6.9 g (28.8 mmol) of 6,7-difluoro-3-methyl-3,4-dihydro-5-oxa-2a-aza-acenaphthylene-1,2-dione (Example 30) in 250 mL of 4.5% aqueous sodium hydroxide is treated dropwise with 16.4 mL of 30% hydrogen peroxide over 1 hour. The reaction is filtered to remove a trace of insoluble material and the filtrate is acidified to pH 4.5 with acetic acid. After cooling to 5° C., the precipitate is removed by filtration, washed with water and dried in vacuo to give 5.5 g of the title compound, mp 200–202° C.

Provenance & Evidence