Iodine → 2-Cyclopenten-1-one, 2-pentyl-

In a 100 ml four-neck flask fitted with a thermometer, a reflux condenser and a stirrer were placed 2-pentylidenecyclopentanone (30 g) synthesized in Reference Example 4, cyclopentanone (31.6 ml) and iodine (30 mg), followed by 4 hours of the reaction under refluxing. The reaction mixture was washed with water and the layers were separated from each other. 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 cyclopentanone, whereby a crude product (30.2 g) was obtained. The product was distilled using a Claisen distillation apparatus to obtain 25.3 g of 2-pentyl-2-cyclopentenone (boiling point: 101° C./900 Pa; GC purity: 97.9%).

1. customIn a 100 ml four-neck flask fitted with a thermometer, a reflux condenser and a stirrer
2. customfollowed by 4 hours of the reaction
3. temperatureunder refluxing
4. washThe reaction mixture was washed with water
5. customthe layers were separated from each other
6. washThe resulting organic layer was washed with saturated brine
7. customseparated
8. customThe organic layer was evaporated on a rotary evaporator under reduced pressure
9. customto recover cyclopentanone, whereby a crude product (30.2 g)
10. customwas obtained
11. distillationThe product was distilled
12. distillationa Claisen distillation apparatus

ORD record

ord-995c1381a8524c619223a8a2f4350712

Source dataset

uspto-grants-2004_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06833481B2