Reaktion #161329

Reaktionsgleichung

3-amino-4-phenylaminobenzoic acid

acetyl chloride

→

title compound

Ausbeute 83.7%

2-methyl-1-phenylbenzimidazole-5-carboxylic acid

Ausbeute 83.7%

Lösungsmittel

toluene

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthis was refluxed
2. 2
   Extraktionwas extracted with dilute aqueous sodium hydroxide solution (10%, 200 mL)
3. 3
   SonstigeAfter separating the dark orange aqueous layer, it
4. 4
   Temperaturwas cooled in ice (5 to 10° C.)
5. 5
   workup.ADDITIONconcentrated hydrochloric acid (12 M) was added to the liquid
6. 6
   Sonstigeto give approx. pH 4
7. 7
   FiltrationThe precipitated crystals were filtered off
8. 8
   Waschenwashed with distilled water
9. 9
   Sonstigedried under reduced pressure
10. 10
    Temperaturwith heating

Vorschrift

A 2-neck flask was charged with 3-amino-4-phenylaminobenzoic acid (see Synthesis Example 1-2) (1.40 g, 6.35 mmol) and anhydrous toluene (15 mL) and this was refluxed. To this was added dropwise over approx. 15 minutes acetyl chloride (1.00 g, 12.70 mmol) in toluene solution (approx. 2.5 mL), and this was stirred under these conditions for 2.5 hours. This was allowed to cool to room temperature, and was extracted with dilute aqueous sodium hydroxide solution (10%, 200 mL). After separating the dark orange aqueous layer, it was cooled in ice (5 to 10° C.), and concentrated hydrochloric acid (12 M) was added to the liquid to give approx. pH 4. The precipitated crystals were filtered off, washed with distilled water, and dried under reduced pressure with heating to yield the title compound (1.34 g, 83.5% yield) as a light purple solid.

Quelle