Sodium Phosphate, Dibasic → 4-Fluoro-2-methylbenzoic acid

HRID 374615

Reaction equation

[CH3:1][C:2]1[CH:16]=[C:15]([F:17])[CH:14]=[CH:13][C:3]=1[C:4](C1C=CC(C)=CC=1)=[O:5].ClC1C=CC=C(C(OO)=[O:26])C=1.P([O-])([O-])(O)=O.[Na+].[Na+].C(=O)([O-])O.[Na+]>ClCCl.O>[CH3:1][C:2]1[CH:16]=[C:15]([F:17])[CH:14]=[CH:13][C:3]=1[C:4]([OH:5])=[O:26]

Participants

Conditions

Temperature: 40 °C

Procedure

2.3 g (10 mmol) of 2-methyl-4-fluoro-4'-methylbenzophenone were added dropwise at 20° C., under inert gas, to 3.8 g (12 mmol) of 3-chloroperbenzoic acid (55%) in 40 ml of dichloromethane and 14.2 g (0.1 mol) of disodium hydrogenphosphate and the reaction mixture was then heated for 8 h at 40° C. It was monitored by gas chromatography and, if the conversion was incomplete, a further 2.5 g (8 mmol) of 3-chloroperbenzoic acid were added. 100 g of water were added 4 hours later and the mixture was neutralized with sodium hydrogencarbonate solution. The phases were separated, the aqueous phase was extracted with dichloromethane and the solvent was distilled off. The residue was boiled for 4 h with 100 g of 70% sulfuric acid and then poured on to 200 g of ice. Extraction and crystallization gave 1.15 g (7.5 mmol, 5%) of 2-methyl-4-fluorobenzoic acid. If the reaction is carried out under these conditions with 9.2 g (15 mmol) of ®Oxone (=potassium peroxomonosulfate) instead of with 3-chloroperbenzoic acid, essentially the same result is obtained.

Workup

customThe phases were separated
extractionthe aqueous phase was extracted with dichloromethane
distillationthe solvent was distilled off
additionpoured on to 200 g of ice
extractionExtraction and crystallization

Sources & evidence

ORD record: ord-a840222c64bc4678af2e9da71b22e7cf
Source dataset: uspto-grants-1996_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05481032

Linked notes

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