Hydrogen Bromide → 3'-Amino-5'-fluoro-2'-hydroxy-biphenyl-3-carboxylic acid hydrobromide

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Reaction Steps

20 mL of hydrobromic acid was added dropwise to 3′-amino-5′-fluoro-2′-hydroxy-biphenyl-3-carboxylic acid 2f (500 mg, 1.92 mmol) obtained from Step 5 of Example 2 to form white precipitates. The reaction solution was heated to reflux overnight, and then it became clear. The colour of the reaction solution finally was brown. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was concentrated under reduced pressure to obtain a brown solid which was dissolved in 20 mL of ethyl acetate. The mixture was stirred for 20 minutes and filtered to obtain the title compound 3′-amino-5′-fluoro-2′-hydroxy-biphenyl-3-carboxylic acid hydrobromide 26a (344 mg, yield 54.8%) as a grey solid.

Provenance & Evidence