Acetic Anhydride → 3-Chloro-4-acetoxybenzoic acid

Reaction equation

[OH:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[Cl:11].[C:12](OC(=O)C)(=[O:14])[CH3:13]>>[C:12]([O:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[Cl:11])(=[O:14])[CH3:13]

Participants

Reactant 2

HCID 7918Acetic Anhydride

HCID 198603-Chloro-4-hydroxybenzoic acid

Product 1

HCID 106562963-Chloro-4-acetoxybenzoic acidYield 52%

Procedure

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.

Workup

additionA mixture of 10 g
distillationExcess acetic anhydride is distilled under vacuum
additionthe residue diluted
additionadded
filtrationthe precipitated crystals filtered
customRecrystallization from toluene
customgives 6.5 g

Sources & evidence

ORD record: ord-719aea01a4cf40cf9d75d0c5817b5ac9
Source dataset: uspto-grants-1979_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04151297

Reaction notes

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