Sulfuric Acid → 3-Chloro-4-acetoxybenzoic acid

HRID 1003355

Reaction equation

O.[Cl:2][C:3]1[CH:4]=[C:5]([CH:9]=[CH:10][C:11]=1[OH:12])[C:6]([OH:8])=[O:7].ClC1C=[C:16](C=CC=1O)[C:17](O)=[O:18].S(=O)(=O)(O)O>C(OC(=O)C)(=O)C>[C:17]([O:12][C:11]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[Cl:2])(=[O:18])[CH3:16]

Participants

Conditions

Temperature: 100 °C

Procedure

3-Chloro-4-hydroxybenzoic acid hemihydrate (10.16 g, 56 mmol) was dissolved in 20 ml of acetic anhydride, followed by the addition of 0.5 ml of concentrated sulfuric acid. The resulting mixture was stirred at 100° C. for 3 hours and was then allowed to stand overnight at room temperature. The precipitate was collected by filtration and then washed with benzene, whereby 8.95 g of 4-acetoxy-3-chlorobenzoic acid were obtained (yield: 75%, melting point: 149-151° C.). A mixture of 8.95 g (41.7 mmol) of 4-acetoxy-3-chlorobenzoic acid and 22.23 g (167 mmol) of aluminum chloride was then heated at 180° C. for 3 hours. Subsequent to the addition of ice and 1N hydrochloric acid, the resultant mixture was extracted with ethyl acetate. The organic layer was washed with water and was then dried over MgSO4. The solvent was distilled off under reduced pressure and the residue was recrystallized from ethyl acetate, whereby 2.97 g of the title compound were obtained as yellow powder (yield: 33%).

Workup

waitto stand overnight at room temperature
filtrationThe precipitate was collected by filtration
washwashed with benzene

Sources & evidence

ORD record: ord-4743a01007e14990be8d0b7dc4a33db6
Source dataset: uspto-grants-2000_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06046212

Linked notes

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