2-Amino-6-chlorobenzoic acid → 5-Chloro-2-(2,6-difluoro-phenyl)-benzo[d][1,3]oxazin-4-one

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Reaction Steps

6-Chloroanthranilic acid (0.566 g), 2,6-difluorobenzoyl chloride (0.93 mL) and triethyl amine/toluene (1/1) (18 mL) were reacted as described under (10). Reaction time 2 days. Extraction between ethyl acetate (100 mL) and HCl (2N, 100 mL), followed by separation of the organic layer, drylng over MgSO4, filtering and evaporation gave a crude product which was dissolved in warm THF (20 mL) and precipitated with hexane. The resulting mixture was further purified on a silicagel column using dichloromethane as eluent. The isolated fraction was dissolved in warm THF (20 mL) and precipitated with hexane, ylelding 5-chloro-2-(2,6-difluoro-phenyl)-benzo[d][1,3]oxazin-4-one (0.65 g) mp. 176 C, MS m/e: 293/295 M+.

Provenance & Evidence