Pyridine → 4-(5-Chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid [4-(5-oxo-4,5-dihydro-[1,2,4]oxadiazol-3-yl)-phenyl]-amide

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Reaction Conditions

Reaction Steps

A solution of 4-(5-chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid [4-(N-hydroxycarbamimidoyl)-phenyl]-amide (97 mg, 0.19 mmol) in dimethylformamide (2.0 mL) was treated with pyridine (0.020 mL, 0.20 mmol) and the mixture was cooled at 0° C. Chloroformic acid 2-ethylhexyl ester (36 mg, 0.19 mmol) was added dropwise and the mixture was stirred at 0° C. for 30 min. The mixture was diluted with water and extracted three times with ethyl acetate. The combined organic extracts were dried over sodium sulfate and evaporated. The residue was suspended in xylene (8.0 mL) and refluxed for 2 hours. Upon cooling to room temperature a solid precipitated, which was filtered and dried under high vacuum. 4-(5-Chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid [4-(5-oxo-4,5-dihydro-[1,2,4]oxadiazol-3-yl)-phenyl]-amide was obtained as a white solid, 74 mg (73%), MS (ISP): m/e=541.1, 542.7 (M−H).

Provenance & Evidence