Hydrochloric Acid → Ethyl 5-iodobenzo[b]thiophene-2-carboxylate

Temperature

0 °C

To 5-amino-benzo[b]thiophene-2-carboxylic acid ethyl ester (18.37 g, 83.02 mmol) was added an aqueous HCl solution (21 mL conc. HCl in 200 mL H2O, 252 mmol)) and the resulting mixture was cooled to 0° C. A solution of NaNO2 (6.02 g in 60 mL H2O, 87.25 mmol) was added and the mixture was allowed to stir at 0° C. for 10 min. A solution of NaI (13.07 g in 60 mL H2O, 87.20 mmol) was added slowly. The reaction mixture became difficult to stir during the addition of NaI. A total of 300 mL of water was added in several portions. After the addition was complete, the reaction was warmed to rt and allowed to stir at rt for 2 h. The mixture was then diluted with CH2Cl2 (800 mL) and water (100 mL). The organic layer was separated, washed with 200 mL of saturated NaHCO3 and dried over Na2SO4. After filtration, the filtrate was concentrated and the residue was filtered through a pad of silica gel, washing with EtOAc/hexanes (0% to 10%). The filtrate was then concentrated and the residue was recrystallized from MeOH to give 5-iodo-benzo[b]thiophene-2-carboxylic acid ethyl ester as light orange solid. MS (EI): cal'd 332.9 (MH+), exp 333.1 (MH+).

1. additionAfter the addition
2. temperaturethe reaction was warmed to rt
3. stirringto stir at rt for 2 h
4. customThe organic layer was separated
5. washwashed with 200 mL of saturated NaHCO3
6. dry with materialdried over Na2SO4
7. filtrationAfter filtration
8. concentrationthe filtrate was concentrated
9. filtrationthe residue was filtered through a pad of silica gel
10. washwashing with EtOAc/hexanes (0% to 10%)
11. concentrationThe filtrate was then concentrated
12. customthe residue was recrystallized from MeOH

ORD record

ord-b30e437040754427a776e02b4a5a6fd4

Source dataset

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07935724B2