反应详情

21.0 g of 5-bromo-2-[(N,N-dimethylcarbamoyl)thio]benzaldehyde was dissolved in 50 ml of methyl orthoformate. The resulting solution was mixed with 1.0 g of p-toluenesulfonate, and refluxed under heating for 50 minutes. After cooling, the resulting reaction solution was poured into saturated sodium bicarbonate solution and extracted with benzene. The resulting organic layer was dried to remove the solvent. The residue thus obtained was dissolved in 100 ml of methanol, followed by adding 37 ml of 2N sodium hydroxide and by refluxing under heating for 1 hour in a stream of nitrogen. After cooling, the resulting reaction solution was adjusted to pH 1 with concentrated hydrochloric acid, extracted with benzene, and then dried to remove the solvent. The residue thus obtained was dissolved in 20 ml of acetone and added dropwise, at room temperature, to a stirred mixture consisting of 6.74 g of chloroacetone, 22.1 g of anhydrous potassium carbonate and 150 ml of acetone. After 30 minutes of stirring, the resulting reaction mixture was refluxed under heating for 30 minutes. After cooling, insoluble materials were removed by filtration, and the resulting filtrate was concentrated to dryness. The thus obtained residue was purified by silica gel column chromatography using toluene as an elution solvent and the resulting product was recrystallized from ethanol to obtain 7.5 g of 2-acetyl-5-bromobenzo[b]thiophene.

1. temperaturerefluxed
2. temperatureunder heating for 50 minutes
3. temperatureAfter cooling
4. customthe resulting reaction solution
5. extractionextracted with benzene
6. customThe resulting organic layer was dried
7. customto remove the solvent
8. customThe residue thus obtained
9. temperatureby refluxing
10. temperatureunder heating for 1 hour in a stream of nitrogen
11. temperatureAfter cooling
12. customthe resulting reaction solution
13. extractionextracted with benzene
14. customdried
15. customto remove the solvent
16. customThe residue thus obtained
17. additionadded dropwise, at room temperature, to a stirred mixture
18. customthe resulting reaction mixture
19. temperaturewas refluxed
20. temperatureunder heating for 30 minutes
21. temperatureAfter cooling
22. custominsoluble materials were removed by filtration
23. concentrationthe resulting filtrate was concentrated to dryness
24. customThe thus obtained residue was purified by silica gel column chromatography
25. customthe resulting product was recrystallized from ethanol