Reaktion #832829

Reaktionsgleichung

[1α,3β,7ξ]-7-bromo-24,24-difluorocholest-5-en-1,3,25-triol 1,3-diacetate

s-collidine

xylene

→

[1α,3β]-24,24-difluorocholesta-5,7-dien-1,3,25-triol 1,3-diacetate

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated
2. 2
   Temperaturcooled
3. 3
   WaschenThis solution was washed with 10% aqueous sulfuric acid, and saturated aqueous sodium bicarbonate solution
4. 4
   TrocknenThe organic phase was dried over anhydrous magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Sonstigeevaporated to dryness
7. 7
   SonstigeThe residue was purified by column chromatography on 0.06-0.20 mm silica gel

Vorschrift

A mixture of 1.33 g (0.0019 mol) of [1α,3β,7ξ]-7-bromo-24,24-difluorocholest-5-en-1,3,25-triol 1,3-diacetate, 0.8 mL of s-collidine and 10 mL of xylene was heated at reflux (140° C.) for 0.5 hr and cooled. The mixture was diluted with 30 mL of benzene. This solution was washed with 10% aqueous sulfuric acid, and saturated aqueous sodium bicarbonate solution. The organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The residue was purified by column chromatography on 0.06-0.20 mm silica gel to yield [1α,3β]-24,24-difluorocholesta-5,7-dien-1,3,25-triol 1,3-diacetate, [α]D25 -31° (c 0.4, CHCl3), mp 130°-132°. UV max (C2H5OH) 261 (ε 7750), 270 (ε 11,200), 281 (ε 12,100) and 293 (ε 7100).

Quelle