Acetic Acid → Ethyl 5-bromothiophene-2-carboxylate

To 1.092 g (5.7157 mmol) of 5-bromothiophene-2-carboxaldehyde was added sequentially, 1.507 g (30.75 mmol) sodium cyanide, 60 ml ethanol, 602.5 mg (10.04 mmol) of acetic acid and 10.62 g (122.16 mmol) of manganese dioxide. This mixture was stirred at room temperature for 24 hours, then filtered through celite and the residue washed several times with ether. The combined filtrates were concentrated, then the residue taken up in water and extracted with 3×75 ml ether. Combined ether extracts were washed with saturated NaHCO3, saturated NaCl, dried (MgSO4), concentrated in vacuo and kugelrohr distilled (70° C.; 0.1 mm) to give the captioned compound as a pale yellow oil. PMR (CDCl3): δ1.3 (3H, t, J~7 Hz), 4.35 (2H, t, J~7 Hz), 7.12 (1H, d, J~4 Hz), 7.6 (1H, d, J~4 Hz).

1. filtrationfiltered through celite
2. washthe residue washed several times with ether
3. concentrationThe combined filtrates were concentrated
4. extractionextracted with 3×75 ml ether
5. washCombined ether extracts were washed with saturated NaHCO3, saturated NaCl
6. dry with materialdried (MgSO4)
7. concentrationconcentrated in vacuo and kugelrohr
8. distillationdistilled (70° C.; 0.1 mm)

ORD record

ord-0c66dc6006fc451db66b61c6f32fb2b2

Source dataset

uspto-grants-1990_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04980484