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

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.

1. customThe mixture was reacted at room temperature for 1 hour
2. concentrationThe mixture was concentrated under reduced pressure
3. additionThe residue was diluted with 30 mL of ethyl acetate
4. filtrationThe mixture was filtered
5. washthe filter cake was washed with ethyl acetate
6. customdried

ORD record

ord-58c7d0ac16a64509b275f345c11c168c

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08367710B2