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

4-(3-Amino-2-methoxy-phenyl)-thiophene-2-carboxylic acid hydrobromide 19b (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 mixture was added with 5 mL of methanol and 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 19c (80 mg, yield 17.5%) as a grey solid.

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

ORD-Eintrag

ord-b51b34059dbc4dc5a7f1257de5b209e4

Quelldatensatz

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09120762B2