Diethyl Ether → Diethyl 2-pent-4-enylpropanedioate

7.05 g of sodium were dissolved in a solution of 40 g of diethyl malonate in 175 ml of ethanol. The still warm solution (50° C.) was treated dropwise within 15 minutes with 45.6 g of 5-bromo-1-pentene and the mixture was heated to boiling for 2 hours. After cooling the reaction mixture was poured into 500 ml of diethyl ether and 300 ml of semi-saturated sodium chloride solution. The aqueous phase was separated and back-extracted twice with 200 ml of diethyl ether each time. The organic phases were washed twice with 150 ml of semi-saturated sodium chloride solution each time dried over sodium sulphate, filtered and concentrated. Chromatographic separation of the resulting, yellow liquid (55.2 g) on silica gel with hexane/ethyl acetate (vol. 95:5) gave 33.2 g of diethyl (4-pentenyl)malonate as a colourless liquid.

1. temperaturethe mixture was heated
2. temperatureAfter cooling the reaction mixture
3. customThe aqueous phase was separated
4. extractionback-extracted twice with 200 ml of diethyl ether each time
5. washThe organic phases were washed twice with 150 ml of semi-saturated sodium chloride solution each time
6. dry with materialdried over sodium sulphate
7. filtrationfiltered
8. concentrationconcentrated
9. customChromatographic separation of the resulting, yellow liquid (55.2 g) on silica gel with hexane/ethyl acetate (vol. 95:5)

ORD-Eintrag

ord-9b90b94308a249569e470052ae31f2b0

Quelldatensatz

uspto-grants-1986_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04621901