Boron tribromide → 5-(3-Amino-2-hydroxy-5-methyl-phenyl)-thiophene-2-carboxylic acid hydrobromide

Participants

Reaction Steps

5-(3-Amino-2-methoxy-5-methyl-phenyl)-thiophene-2-carboxylic acid 24c (0.26 g, 1 mmol) was dissolved in 20 mL of dichloromethane followed by addition of boron tribromide (5 mL, 35.32 mmol/L). The mixture was reacted at room temperature for 1 hour. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was concentrated under reduced pressure. The residue was diluted with 30 mL of ethyl acetate and stirred for 0.5 hours. The mixture was filtered and the filter cake was washed with ethyl acetate and dried to obtain the title compound 5-(3-amino-2-hydroxy-5-methyl-phenyl)-thiophene-2-carboxylic acid hydrobromide 24d (0.15 g, yield 45.5%) as a grey solid.

Provenance & Evidence