Boron tribromide → 3-[(3-{[(5-Chloro-2-thienyl)sulfonyl]amino}-4-hydroxy-1H-indazol-1-yl)methyl]benzamide

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Reaction Steps

A suspension of 3-{[3-{[(5-chloro-2-thienyl)sulfonyl]amino}-4-(methyloxy)-1H-indazol-1-yl]methyl}benzamide (for a preparation see Example 64) (50.0 mg, 0.105 mmol) in anhydrous DCM (1.5 mL) under nitrogen atmosphere was treated with boron tribromide solution in DCM (1M, 0.105 mL, 0.105 mmol) at room temperature, and the mixture was stirred at room temperature for 45 min. A further 0.2 ml portion of boron tribromide solution was added and the reaction mixture was stirred at room temperature for 90 min. Saturated aqueous sodium bicarbonate solution was added dropwise to quench the reaction. The reaction was then partitioned between further saturated aqueous sodium bicarbonate solution and 10% methanol in ethyl acetate (off white precipitate was present, which was insoluble in both the organic and aqueous layer). The organic layer was separated, passed through a hydrophobic frit and evaporated in-vacuo to yield an off white solid (58 mg), which was dissolved in MeOH-DMSO (1:1) (1 mL) and purified by MDAP on Sunfire C18 column eluting with solvents A/B (A: 0.1% v/v solution of formic acid in water, B: 0.1% v/v solution of formic acid in acetonitrile 25 min run). The appropriate fraction was evaporated in-vacuo to yield a white solid (17 mg, 35%). LCMS (System B) RT=2.18 min, ES+ve m/z 463/465 (M+H)+.

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