Water → HCID 14347811, compound

Participants

Reaction Steps

Sodium hydroxide (0.7 g) and water (10 ml) were added to a mixture of 4-ethoxycarbonylmethyl-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (3.7 g) and ethanol (20 ml), and the mixture was refluxed under heating for 5 hours. After the reaction, the solvent was concentrated, and dissolved in water (50 ml), and washed with methylisobutyl ketone, the aqueous layer was acidified with hydrochloric acid, and extracted with methyl isobutyl ketone, then dried with anhydrous sodium sulfate. After the solvent was distilled off, the residue was mixed with a mixed solvent of toluene-hexane (1:5), the mixture was filtered off to give the desired 4-carboxymethyl-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (3.2 g). mp. 183°-184° C.

Provenance & Evidence