Reaktion #54995

Reaktionsgleichung

4-hydroxy-3-chlorobenzoic acid

acetic anhydride

→

4-Acetoxy-3-chlorobenzoic acid

Ausbeute 52.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONA mixture of 10 g
2. 2
   workup.DISTILLATIONExcess acetic anhydride is distilled under vacuum
3. 3
   workup.ADDITIONthe residue diluted
4. 4
   workup.ADDITIONadded
5. 5
   Filtrationthe precipitated crystals filtered
6. 6
   SonstigeRecrystallization from toluene
7. 7
   Sonstigegives 6.5 g

Vorschrift

A mixture of 10 g. 4-hydroxy-3-chlorobenzoic acid and 50 ml. of acetic anhydride is refluxed for two hours. Excess acetic anhydride is distilled under vacuum and the residue diluted and stirred with a mixture of methanol (100 ml.) and water (20 ml.) at about 50° for 30 minutes. The mixture is then reduced to low volume under vacuum, water added and the precipitated crystals filtered. Recrystallization from toluene gives 6.5 g. (52% yield) m.p. 162°-163° C.

Quelle