2,3-Dichloropropene → 5-Bromo-2-methyl-1-benzothiophene

Temperature

55 °C

A mixture of 4-bromothiophenol (5.0 g, 26.4 mmol), 2,3-dichloro-1-propene (2.6 g, 23.8 mmol) and potassium carbonate (4.4 g, 31.7 mmol) in acetone (20 ml) was stirred at 55° C. for 6 hours. After cooling to room temperature, acetone was removed under vacuum and the residue was taken into water and extracted with ethyl acetate twice. The combined organic layers were washed with 1 M sodium hydroxide, water and brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. Diethylaniline (30 ml) was added to the residue and the resulting mixture was stirred at 185° C. for 15 hours. Ethyl acetate was added to the cooled mixture and diethylaniline was removed by washing with 1 M HCl four times. The organic layer was dried over sodium carbonate to give 5-bromo-2-methylbenzothiophene (5.3 g, 88%, 95.1% AUC GC): 1H NMR (300 MHz, CDCl3) δ 7.70 (s, 1H), 7.52 (d, J=8.7 Hz, 1H), 7.26 (dd, J=8.7, 1.8 Hz, 1H), 6.83 (s, 1H), 2.51 (s, 3H).

1. temperatureAfter cooling to room temperature
2. customacetone was removed under vacuum
3. extractionextracted with ethyl acetate twice
4. washThe combined organic layers were washed with 1 M sodium hydroxide, water and brine
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated under vacuum
8. additionDiethylaniline (30 ml) was added to the residue
9. stirringthe resulting mixture was stirred at 185° C. for 15 hours
10. additionEthyl acetate was added to the cooled mixture and diethylaniline
11. customwas removed
12. washby washing with 1 M HCl four times
13. dry with materialThe organic layer was dried over sodium carbonate

ORD record

ord-113b79cdc31c475bb7e9916cf687a159

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08236796B2