Reaktion #8318

Reaktionsgleichung

ethyl picolinate

ethyl picolinate

lepidine

potassium bis(trimethylsilyl)amide

→

yellow-brown solid

Ausbeute 82.0%

1-(2-Pyridyl)-2-(4-quinolyl)ethan-1-one

Ausbeute 82.0%

Lösungsmittel

toluene

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeIn a 3-neck 3-liter round bottom flask equipped with two addition funnels
2. 2
   workup.ADDITIONOne addition funnel
3. 3
   workup.ADDITIONthe base added to the reaction mixture dropwise over 40 min
4. 4
   SonstigeThe ice bath is removed
5. 5
   workup.STIRRINGthe reaction mixture stirred at ambient temperature for 3 h
6. 6
   SonstigeThe reaction is quenched with water (20 mL) and after 5 min formic acid
7. 7
   workup.ADDITIONadded until the pH
8. 8
   EinengenThe mixture is concentrated in vacuo
9. 9
   Sonstigepartitioned between ethyl acetate (300 mL) and brine-sodium bicarbonate (300 mL) mixture
10. 10
    WaschenThe organic layer is washed with brine and sodium bicarbonate
11. 11
    Trocknendried over sodium sulfate
12. 12
    Einengenconcentrated
13. 13
    SonstigeThe product is chromatographed on SiO2 (27-30% acetone in hexane)

Vorschrift

In a 3-neck 3-liter round bottom flask equipped with two addition funnels is dissolved lepidine (10.0 mL, 75.63 mmol) in tetrahydrofuran (200 mL). One addition funnel is charged with ethyl picolinate (20.43 mL, 151.26 mmol) and the other with 0.5 M potassium bis(trimethylsilyl)amide (166.4 mL, 83.19 mmol) in toluene. The solution is cooled to −78° C. and the base added to the reaction mixture dropwise over 40 min. The reaction mixture is stirred an additional 1.5 h and ethyl picolinate is added rapidly. The ice bath is removed and the reaction mixture stirred at ambient temperature for 3 h. The reaction is quenched with water (20 mL) and after 5 min formic acid added until the pH is slightly less than 7. The mixture is concentrated in vacuo and partitioned between ethyl acetate (300 mL) and brine-sodium bicarbonate (300 mL) mixture. The organic layer is washed with brine and sodium bicarbonate, dried over sodium sulfate, and concentrated. The product is chromatographed on SiO2 (27-30% acetone in hexane) to yield 15.31 g (82%) of a yellow-brown solid.

Quelle