Ethanol → 5-Amino-4-(3-bromo-benzenesulfonyl)-thiophene-2-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

4-(3-Bromo-benzenesulfonyl)-5-nitro-thiophene-2-carboxylic acid methyl ester (407 mg, 1.0 mmol, Example 20: step b) was dissolved into EtOH (6 mL). To this was added ammonium chloride (535 mg, 10 mmol) dissolved into water (3 mL). This mixture was heated to 50° C. with stirring and then iron (277 mg, 5 mmol) was added. The reaction was then heated to 80° C. with stirring for 12 hours. The reaction mixture was then filtered through Celite® and washed with 10% DCM/MeOH. Removal of the solvents in vacuo yielded the title compound (598 mg, quantitative yield) which was used without further purification. 1H-NMR (CDCl3): δ 8.05 (s, 1H), 7.84–7.86 (m, 1H), 7.70–7.75 (m, 1H), 7.56 (s, 1H), 7.40 (m, 1H), 6.02 (br s, 2H), 3.85 (s, 3H). ESI-MS (m/z): Calcd. for C12H10BrNO4S2: 375.9 (M+H); found: 376.1.

Provenance & Evidence