Sodium Hydroxide → 2H-Pyran-2-one, tetrahydro-5-pentyl-

Temperature

0 °C

1560.0 g of ethanol and 663.0 g (max. 2.74 mol) of 82.7% methyl 4-formylnonanoate obtained in Example 1 are placed in a four-liter round-bottomed flask with a mechanical stirrer and a thermometer, and the mixture is cooled to 0° C. 41.6 g (1.10 mol) of sodium borohydride are then added dropwise over four hours, without exceeding 5° C. in the bulk. Stirring is continued after the end of the addition for a further 24 hours at 0° C. 1900.0 g of aqueous 10% sodium hydroxide solution are added dropwise over two hours, without exceeding 10° C. in the bulk. A white precipitate forms. Stirring is continued until the dissolution of the precipitate is complete (about two hours). The flask is placed under a vacuum of about 3990 Pa and the ethanol is distilled off. The aqueous phase obtained is extracted twice with 200 ml of a mixture of toluene and hexane (50/50) to remove the neutral products. The aqueous phase is then cooled to 0° C. The resulting phase is acidified with 1900.0 g of 10% hydrochloric acid for three hours, without exceeding 10° C. in the bulk. After the end of the addition, stirring is continued for four hours, while allowing the temperature of the reaction medium to rise to room temperature (20° C.). The phases are allowed to separate by settling and the organic phase is recovered. The aqueous phase is extracted twice with 200 ml of toluene. The organic phases are combined and are washed twice with 100 ml of water and once with 200 ml of brine, and then concentrated under reduced pressure (3990 Pa). 696.0 g of a crude product are obtained, and are then blanched at 133 Pa to give 468.0 g of 86.1% 5-pentyltetrahydropyran-2-one. After distillation on a Vigreux column, a core fraction of 289.0 g (1.70 mol) of 98.3% 5-pentyltetrahydropyran-2-one is obtained (90-2° C./27 Pa) in a yield of 61%.

1. customwithout exceeding 5° C. in the bulk
2. additionafter the end of the addition for a further 24 hours at 0° C
3. customwithout exceeding 10° C. in the bulk
4. stirringStirring
5. dissolutionis continued until the dissolution of the precipitate
6. custom(about two hours)
7. distillationthe ethanol is distilled off
8. customThe aqueous phase obtained
9. extractionis extracted twice with 200 ml of a mixture of toluene and hexane (50/50)
10. customto remove the neutral products
11. temperatureThe aqueous phase is then cooled to 0° C
12. customwithout exceeding 10° C. in the bulk
13. additionAfter the end of the addition
14. stirringstirring
15. waitis continued for four hours
16. customto rise to room temperature
17. custom(20° C.)
18. customto separate
19. customthe organic phase is recovered
20. extractionThe aqueous phase is extracted twice with 200 ml of toluene
21. washare washed twice with 100 ml of water and once with 200 ml of brine
22. concentrationconcentrated under reduced pressure (3990 Pa)
23. custom696.0 g of a crude product are obtained

ORD record

ord-86055e21d7ad4ccf92ba5d4e2c1a4fe5

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08440608B2