反应详情

In a 300 ml four-neck flask fitted with a thermometer, a reflux condenser and a stirrer were placed 2-(1-hydroxyheptyl)cyclopentanone (70 g) synthesized in Reference Example 3, oxalic acid (0.7 g) and toluene (140 ml), and the whole was refluxed to allow dehydration to proceed. The formed water was removed and the reaction was continued until water was not formed any more (about 2.5 hours). The reaction mixture was washed with water and the layers were separated from each other. Further, the resulting organic layer was washed with saturated brine and separated. The organic layer was evaporated on a rotary evaporator under reduced pressure to recover toluene and unreacted cyclopentanone, whereby a crude product (63 g) was obtained. The product was distilled using a Claisen distillation apparatus to obtain 55 g of 2-heptylidenecyclopentanone (boiling point: 56° C./400 Pa; GC purity: 98.5%).

1. customIn a 300 ml four-neck flask fitted with a thermometer, a reflux condenser and a stirrer
2. temperaturethe whole was refluxed
3. customThe formed water was removed
4. customwas not formed any more (about 2.5 hours)
5. washThe reaction mixture was washed with water
6. customthe layers were separated from each other
7. washFurther, the resulting organic layer was washed with saturated brine
8. customseparated
9. customThe organic layer was evaporated on a rotary evaporator under reduced pressure
10. customto recover toluene and unreacted cyclopentanone, whereby a crude product (63 g)
11. customwas obtained
12. distillationThe product was distilled
13. distillationa Claisen distillation apparatus