反应详情

温度

95 °C

Dry HCl is introduced into 2.57 g (0.01 mol) of the 5-(2',2',2'-trichloroethyl)-6-oxaspiro(3.4)-octan-7-one, produced according to Example 11, in 30 ml of absolute ethanol. After the reaction has subsided (temperature rise up to 55° C.), the reaction mixture is concentrated by evaporation; it is then taken up in absolute ethanol, and 0.011 mol of sodium ethylate (produced from 0.27 g of sodium in ethanol) is added. After a stirring period of 30 minutes, the mixture is concentrated by evaporation; 38 ml (about 0.06 mol) of 10% sodium hydroxide solution is added, and stirring is maintained at 95° C. for 6 hours. After cooling, the mixture is washed with several portions of diethyl ether, acidified with sulphuric acid, and extracted with diethyl ether. The ether extracts after drying over sodium sulphate are concentrated by evaporation. By filtration of the residue from the ten-fold amount by weight of silica gel (eluant: hexane/diethyl ether in the volume ratio of 1:1), a small amount of strongly polar impurities is removed. After concentration of the filtrate by evaporation, there is obtained 2-(2',2'-dichlorovinyl)spiro(2.3)hexane-1-carboxylic acid of the formula ##STR15## having a melting point of 122°-128° C.

1. customproduced
2. custom(temperature rise up to 55° C.)
3. concentrationthe reaction mixture is concentrated by evaporation
4. concentrationthe mixture is concentrated by evaporation
5. temperatureAfter cooling
6. washthe mixture is washed with several portions of diethyl ether
7. extractionextracted with diethyl ether
8. dry with materialafter drying over sodium sulphate
9. concentrationare concentrated by evaporation
10. filtrationBy filtration of the residue from the ten-fold amount by weight of silica gel (eluant
11. customhexane/diethyl ether in the volume ratio of 1:1), a small amount of strongly polar impurities is removed
12. customAfter concentration of the filtrate by evaporation