Boron tribromide → (7-Hydroxy-1,1-dioxo-1,4-dihydro-1lambda6-benzo[1,2,4]thiadiazin-3-yl)-acetic acid

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Reaction Steps

To a solution of compound 4a (1 g, 3.7 mmol) in dichloromethane (23 mL), a solution of 1.0 M of BBr3 in dichloromethane was added dropwise at 0° C. over 5 minutes. The reaction mixture was stirred at 0° C. to room temperature overnight. LC-MS result confirmed the completion of the reaction. The reaction mixture was poured onto 50 mL of ice which was extracted with EtOAc (150 mL×3). The combined organic layer was dried over MgSO4, filtered, concentrated under reduced pressure and further dried under high vacuum to give 826.8 mg of desired product (10c) as brown foam in 87.2% yield. This crude product was directly used in next step without further purification. LC-MS: (ESI+) m/e=257.10 [M+1]+ (exact ms: 256.02).

Provenance & Evidence