Reaktion #2151786

Reaktionsgleichung

sodium bicarbonate

3-(5,6-dimethyl-1H-benzoimidazol-2-yl)-5-methoxy-1H-indazole

boron tribromide

water

→

3-(5,6-dimethyl-1H-benzoimidazol-2-yl)-1H-indazol-5-ol

Ausbeute 71.1%

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was then heated
2. 2
   Temperaturat reflux temperature for 4 hours
3. 3
   Temperaturcooled
4. 4
   Extraktionthis mixture was then extracted twice with ethyl acetate
5. 5
   WaschenThe combined extracts were washed with brine
6. 6
   Trocknendried over magnesium sulfate
7. 7
   Sonstigeevaporated
8. 8
   workup.ADDITIONThe pale yellow solid residue was subjected to flash column chromatography on silica eluting with a mixture of ethyl acetate and triethylamine (99:1

Vorschrift

A solution of 3-(5,6-dimethyl-1H-benzoimidazol-2-yl)-5-methoxy-1H-indazole [34 mg, Example 235(b)] at 0° C. was treated with a solution of boron tribromide in dichloromethane (0.30 mL, 1M). The mixture was then heated at reflux temperature for 4 hours, then cooled and then treated dropwise with water. The pH was adjusted to between 7 and 8 by the addition of saturated aqueous sodium bicarbonate solution and this mixture was then extracted twice with ethyl acetate. The combined extracts were washed with brine, then dried over magnesium sulfate and then evaporated. The pale yellow solid residue was subjected to flash column chromatography on silica eluting with a mixture of ethyl acetate and triethylamine (99:1, v/v) to yield 3-(5,6-dimethyl-1H-benzoimidazol-2-yl)-1H-indazol-5-ol (23 mg) as a white solid. LC-MS (METHOD B): RT=2.19 minutes; 279 (M+H)+.

Quelle