Boron tribromide → 4-(3-Amino-2-hydroxy-phenyl)-thiophene-2-carboxylic acid hydrobromide

4-(3-Amino-2-methoxy-phenyl)-thiophene-2-carboxylic acid hydrobromide 51b (360 mg, 1.45 mmol) was dissolved in 5 mL of dichloromethane followed by dropwise addition of boron tribromide (2.8 mL, 5.6 mmol). The reaction mixture was reacted at room temperature for 4.5 hours. The reaction was monitored by TLC until the disappearance of the starting materials and quenched with 5 mL of methanol. The mixture was concentrated under reduced pressure. The residue was diluted with 10 mL of ethyl acetate and stirred for 0.5 hours. The mixture was filtered and the filter cake was dried to obtain the title compound 4-(3-amino-2-hydroxy-phenyl)-thiophene-2-carboxylic acid hydrobromide 51c (80 mg, yield 17.5%) as a grey solid.

1. customThe reaction mixture was reacted at room temperature for 4.5 hours
2. customquenched with 5 mL of methanol
3. concentrationThe mixture was concentrated under reduced pressure
4. additionThe residue was diluted with 10 mL of ethyl acetate
5. filtrationThe mixture was filtered
6. customthe filter cake was dried

ORD record

ord-b8db0c2084044a20937a4bd48897b843

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08367710B2