Reaktion #575293

Reaktionsgleichung

hydrochloric acid

(R)-4-cyano-3-hydroxybutyric acid, ethyl ester

tetrahydrofuran

1-acetylpiperidine

lithium diisopropylamide

tetrahydrofuran

→

(R)-ε-hydroxy-α,γ-dioxo-1-piperidineheptanenitrile

Lösungsmittel

tetrahydrofuran heptane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwhile maintaining the temperature between -40° C. to -50° C.
2. 2
   workup.STIRRINGThe reaction mixture is stirred for 30 minutes at -25° C. to -20° C.
3. 3
   ExtraktionThe aqueous layer is extracted with 500 mL of ethyl acetate
4. 4
   Sonstigethe aqueous layer is separated
5. 5
   Extraktionextracted with 100 mL of ethyl acetate
6. 6
   Einengenconcentrated in vacuo

Vorschrift

To a stirred -10° C. solution of 1-acetylpiperidine (127 g, 1.0 mol) in tetrahydrofuran (1.0 L) is slowly added a solution of lithium diisopropylamide in tetrahydrofuran-heptane (0.5 L of 2M) while maintaining the temperature between -40° C. to -50° C., and the mixture is stirred at -20° C. to -30° C. for 30 minutes. (R)-4-cyano-3-hydroxybutyric acid, ethyl ester (Brower, supra) (40 g, 0.25 mol) as a solution in 200 mL of tetrahydrofuran is then added to the previous mixture. The reaction mixture is stirred for 30 minutes at -25° C. to -20° C., and transferred to a 2.2N aqueous hydrochloric acid solution (1 L). The aqueous layer is extracted with 500 mL of ethyl acetate, the aqueous layer is separated and extracted with 100 mL of ethyl acetate, the extracts are combined and concentrated in vacuo to afford (R)-ε-hydroxy-α,γ-dioxo-1-piperidineheptanenitrile as an oil.

Quelle