Reaktion #82977

Reaktionsgleichung

trichloroacetyl chloride

2,9-dimethylimidazo[1,2-a]benzimidazole

→

2,9-Dimethyl-3-trichloroacetylimidazo[1,2-a]benzimidazole

Lösungsmittel

xylene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeobtained
2. 2
   TemperaturThe mixture is then heated
3. 3
   Temperaturat reflux for two hours until the product which
4. 4
   Sonstigehas initially precipitated
5. 5
   workup.DISSOLUTIONis completely dissolved
6. 6
   TemperaturCool
7. 7
   Filtrationfilter
8. 8
   EinengenConcentrate the mother liquors
9. 9
   workup.ADDITIONadd petroleum ether
10. 10
    SonstigeCombine with the precipitate obtained earlier
11. 11
    SonstigeThe combined precipitates
12. 12
    workup.ADDITIONare treated with an aqueous solution of sodium hydrogen carbonate
13. 13
    Sonstigerecrystallised from ethyl acetate

Vorschrift

Pour 5.45 g (30 mmol) of freshly distilled trichloroacetyl chloride dropwise into a boiling solution of 2,9-dimethylimidazo[1,2-a]benzimidazole (3.7 g; 20 mmol)--obtained as described in Khim. Geterotsikl Soedin, 86, (7), 918-925--in 50 ml of xylene, with vigorous stirring, over a period of 20 to 30 minutes. The mixture is then heated at reflux for two hours until the product which has initially precipitated is completely dissolved. Cool and filter. Concentrate the mother liquors and add petroleum ether. Combine with the precipitate obtained earlier and repeat the operation. The combined precipitates are treated with an aqueous solution of sodium hydrogen carbonate and then recrystallised from ethyl acetate.

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