反应详情

In a flask are placed 5.44 g (0.020 mole) of 3-bromo-2,3-dihydro-2,2-dimethyl-7-nitrobenzofuran (prepared by the method of Example 2, Step A) and 7.45 g (0.020 mole) of tetraethylammonium thiosulfate (prepared by the method of B. Hahn et al., Liebigs Ann. Chem. 1981, 10-19) in 100 mL of absolute ethanol. This mixture is heated at reflux for 24 hours after which the solvent is removed under reduced pressure, leaving a residue. This residue is taken up in 60 mL of diethyl ether which is then filtered to remove inorganic salts. Slowly, 20 mL of a 2N aqueous sodium hydroxide solution is added to the rapidly stirred filtrate. This mixture is stirred for 30 minutes at room temperature after which the aqueous phase is separated from the organic phase. The latter is washed with water, dried over anhydrous sodium sulfate, and filtered. The solvent is evaporated under reduced pressure, leaving a residue which is dissolved in methylene chloride. This solution is passed through a column of silica gel, eluting with methylene chloride. Product-containing fractions are combined, and the solvent is evaporated under reduced pressure, yielding 2,3-dihydro-2,2-dimethyl-7-nitrobenzofuran-3-thione.

1. customIn a flask are placed
2. customprepared by the method of B
3. temperatureThis mixture is heated
4. temperatureat reflux for 24 hours after which the solvent
5. customis removed under reduced pressure
6. customleaving a residue
7. filtrationis then filtered
8. customto remove inorganic salts
9. additionSlowly, 20 mL of a 2N aqueous sodium hydroxide solution is added to the rapidly stirred filtrate
10. customis separated from the organic phase
11. washThe latter is washed with water
12. dry with materialdried over anhydrous sodium sulfate
13. filtrationfiltered
14. customThe solvent is evaporated under reduced pressure
15. customleaving a residue which
16. washeluting with methylene chloride
17. customthe solvent is evaporated under reduced pressure