Reaktion #1069133

Reaktionsgleichung

Isobutyl chloroformate

3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)acrylic acid

triethylamine

2-ethylpiperidine

→

1-[3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)acryloyl]-2-ethylpiperidine

Ausbeute 47.8%

Lösungsmittel

methylene chloride

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGAfter being stirred at the same temperature for 30 minutes
2. 2
   workup.STIRRINGdropwise at -20° C. and the mixture was stirred at -20° C. to 10° C. for 2 hours
3. 3
   Sonstigeevaporated in vacuo
4. 4
   workup.ADDITIONA saturated sodium bicarbonate solution was added to the residue
5. 5
   Extraktionextracted twice with chloroform (50 ml)
6. 6
   ExtraktionThe combined extract
7. 7
   Waschenwas washed with saturated brine (50 ml)
8. 8
   Trocknendried over magnesium sulfate
9. 9
   Sonstigeevaporated in vacuo
10. 10
    SonstigeThe residue was chromatographed on silica gel (40 g) with chloroform as an eluent
11. 11
    workup.ADDITIONThe fractions containing the object compound
12. 12
    Sonstigeevaporated in vacuo

Vorschrift

Isobutyl chloroformate (1.04 g) was added dropwise to a mixture of 3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)acrylic acid (trans isomer) (2.0 g) and triethylamine (0.766 g) in methylene chloride (40 ml) and tetrahydrofuran (10 ml) at -20° C. with stirring. After being stirred at the same temperature for 30 minutes, a solution of 2-ethylpiperidine (0.942 g) in tetrahydrofuran (10 ml) was added thereto dropwise at -20° C. and the mixture was stirred at -20° C. to 10° C. for 2 hours. The mixture was warmed to room temperature and evaporated in vacuo. A saturated sodium bicarbonate solution was added to the residue and extracted twice with chloroform (50 ml). The combined extract was washed with saturated brine (50 ml), dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel (40 g) with chloroform as an eluent. The fractions containing the object compound were combined and evaporated in vacuo to give 1-[3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)acryloyl]-2-ethylpiperidine (trans isomer) (1.30 g) as an oil.

Quelle