Reaktion #50205

Reaktionsgleichung

5-(5-bromo-2-n-propoxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one

triethylamine

tri-o-tolylphosphine

t-butyl acrylate

→

title compound

(E)-3-(1-Methyl-7-oxo-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-n-propoxycinnamic acid t-butyl ester

Lösungsmittel

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was heated
2. 2
   Temperaturunder reflux for 4 hours
3. 3
   Temperaturcooled
4. 4
   Sonstigeevaporated under vacuum
5. 5
   Extraktionextraction with dichloromethane (3×20 ml)
6. 6
   Trocknendried (Na2SO4)
7. 7
   Sonstigeevaporated under vacuum
8. 8
   Sonstigeto give a yellow-green solid
9. 9
   Waschena methanol in dichloromethane elution gradient (0-2% methanol)
10. 10
    Sonstigefollowed by crystallisation from ethyl acetate-hexane

Vorschrift

To a solution of 5-(5-bromo-2-n-propoxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (1.0 g, 0.0025 mol) and triethylamine (0.38 g, 0.0038 mol) in acetonitrile (2 ml), was added palladium(II) acetate (0.03 g, 0.00013 mol), tri-o-tolylphosphine (0.076 g, 0.00025 mol) and t-butyl acrylate (0.48 g, 0.00038 mol). The mixture was heated under reflux for 4 hours, then cooled and evaporated under vacuum. The residue was suspended in water (30 ml) and extraction with dichloromethane (3×20 ml) effected. The organic extracts were combined, dried (Na2SO4) and evaporated under vacuum to give a yellow-green solid. Chromatography on silica gel (12 g), using a methanol in dichloromethane elution gradient (0-2% methanol), followed by crystallisation from ethyl acetate-hexane gave the title compound as a white solid (0.65 g, 58%), m.p. 167°-168° C. Found: C,66.47; H,7.00; N,12.31. C25H32N4O4 requires C,66.35; H,7.13; N,12.38%.

Quelle