Methyl 7-nitrobenzo[b]thiophene-2-carboxylate → Methyl 7-amino-1-benzothiophene-2-carboxylate

To a mixture of 7-nitro-benzo[b]thiophene-2-carboxylic acid methyl ester (100 mg) in acetic acid (4 mL) was added a solution of SnC2.2H2O (10 eq) in 1.5 mL of concentrated HCl. The reaction was stirred at room temperature 12 h. The excess acid was partially removed in vacuo, and the reaction mixture was then poured into a flask (250 mL) and was neutralized with saturated NaHCO3 solution at 0° C. The pH was brought up to pH 9 by adding solid NaHCO3. The resulting aqueous mixture was diluted with EtOAc, and the Tin-by product was removed by filtering through a pad of diatomaceous earth. The pad was rinsed with EtOAc and the combined filtrates were partitioned in a separatory funnel. The aqueous layer was extracted with EtOAc two times times. The combined organics were dried over MgSO4, filtered and concentrated to give the desired 7-amino-benzo[b]thiophene-2-carboxylic acid methyl ester (100%).

1. customThe excess acid was partially removed in vacuo
2. additionthe reaction mixture was then poured into a flask (250 mL)
3. customwas neutralized with saturated NaHCO3 solution at 0° C
4. additionby adding solid NaHCO3
5. additionThe resulting aqueous mixture was diluted with EtOAc
6. customthe Tin-by product was removed
7. filtrationby filtering through a pad of diatomaceous earth
8. washThe pad was rinsed with EtOAc
9. customthe combined filtrates were partitioned in a separatory funnel
10. extractionThe aqueous layer was extracted with EtOAc two times times
11. dry with materialThe combined organics were dried over MgSO4
12. filtrationfiltered
13. concentrationconcentrated

ORD record

ord-3be63abe472f44f9b1eb7d94f1922fc9

Source dataset

uspto-grants-2009_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07550461B2