Reaktion #452144

Reaktionsgleichung

2-propanol

ethyl acetate

diethyl 4-(4-benzofurazanyl)-2-(diethoxymethyl)-1,4-dihydro-6-(trifluoromethyl)-3,5-pyridinedicarboxylate

hydrochloric acid

→

title compound

Ausbeute 7.1%

Diethyl 4-(4-benzofurazanyl)-2-formyl-1,4-dihydro-6-(trifluoromethyl)-3,5-pyridinedicarboxylate

Ausbeute 7.1%

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe resulting solution heated
2. 2
   Temperaturat reflux
3. 3
   SonstigeThe organic phase was separated
4. 4
   Waschenwashed with water, saturated aqueous sodium bicarbonate solution, brine
5. 5
   Trocknendried (MgSO4)
6. 6
   SonstigeEvaporation of the solvent
7. 7
   workup.WAITleft an oil (7.5 g) which
8. 8
   Sonstigewas purified by chromatography on silica (300 g)
9. 9
   Sonstigeether-petroleum ether (60°-80°)
10. 10
    SonstigeThe major component was obtained as an oil which
11. 11
    SonstigeRecrystallisation from 2-propanol

Vorschrift

To a solution of diethyl 4-(4-benzofurazanyl)-2-(diethoxymethyl)-1,4-dihydro-6-(trifluoromethyl)-3,5-pyridinedicarboxylate (7.6 g, 14.5 mmoles) in tetrahydrofuran (100 ml) was added 25% aqueous hydrochloric acid solution (100 ml) and the resulting solution heated at reflux. After 1.5 hours the cooled solution was poured into ethyl acetate (200 ml). The organic phase was separated and washed with water, saturated aqueous sodium bicarbonate solution, brine and dried (MgSO4). Evaporation of the solvent left an oil (7.5 g) which was purified by chromatography on silica (300 g) using ether-petroleum ether (60°-80°) as eluent. The major component was obtained as an oil which gave a solid on trituration with 2-propanol. Recrystallisation from 2-propanol gave the title compound (0.45 g) as yellow crystals mp 94°-5°.

Quelle