Hydrogen Bromide → 2,5-dibromothiophene-3-carbaldehyde

Temperature

0 °C

Thiophene-3-carboxaldehyde (2.54 g, 22.8 mmol) was mixed with 48% aqueous hydrobromic acid (6.8 mL), and ether (6 mL), then cooled at 0° C. A mixture of bromine (7.36 g, 46.0 mmol) and 48% aqueous hydrobromic acid (6.8 mL) was added dropwise under vigorous stir. The reaction mixture was then heated at 50° C. and reacted for 4 h. After reaction, the mixture was diluted with water (100 mL) and extracted with ether (3×50 mL). The organic layers were combined, washed with 10% sodium thiosulfate solution (2×15 mL) and water (30 mL), and dried (Na2SO4). The solvent was removed under reduced pressure to give dark crude product. The crude product was purified by column chromatography on silica gel (hexane/ethyl acetate=5:1). (4.32 g, 70%). 1H NMR (400 MHz, CDCl3, δ/ppm) 9.80 (s, 1H, CHO), 7.34 (s, 1H);

1. additionwas added dropwise under vigorous stir
2. temperatureThe reaction mixture was then heated at 50° C.
3. customreacted for 4 h
4. customAfter reaction
5. extractionextracted with ether (3×50 mL)
6. washwashed with 10% sodium thiosulfate solution (2×15 mL) and water (30 mL)
7. dry with materialdried (Na2SO4)
8. customThe solvent was removed under reduced pressure
9. customto give dark crude product
10. customThe crude product was purified by column chromatography on silica gel (hexane/ethyl acetate=5:1)

ORD record

ord-a2cd36dc1d4f400fb22bb809d732df2d

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08378058B2