P-Toluic Acid → 3,5-Dichloro-4-methylbenzoic acid

HRID 1464314Notes

Reaction equation

HRID 1464314 reaction equation
[CH3:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]([OH:10])=[O:9])=[CH:6][CH:7]=1.[Cl-:11].[Al+3].[Cl-:13].[Cl-]>C(Cl)Cl>[Cl:11][C:3]1[CH:4]=[C:5]([CH:6]=[C:7]([Cl:13])[C:2]=1[CH3:1])[C:8]([OH:10])=[O:9]

Participants

4

Reactant 2

HCID 7470P-Toluic AcidHCID 6451240Aluminum(III) Chloride

Product 1

HCID 185332343,5-Dichloro-4-methylbenzoic acid

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of p-toluic acid (95.0 g,0.698 mole) in methylene chloride (1 liter), was added aluminum chloride (260.0 g,1.948 mole), portionwise, while keeping the reaction temperature below 10° C. When the addition was completed, chlorine gas was bubbled in at such a rate as to keep the temperature below 10° C. The reaction was followed by GLC. After about 4 hours most of the starting material had been converted to the expected compound. The resulting mixture was poured into ice and concentrated hydrochloric acid, and then extracted with ethyl acetate several times. The combined organic layers were washed with water and then dried over anhydrous sodium sulfate. Removing the solvent in the rotavap yielded the crude product as a white solid. Recrystalization from acetone/water yielded 3,5-dichloro-4-methylbenzoic acid with minor impurities 115.4 g (81% yield of product).

Workup

  1. customthe reaction temperature below 10° C
  2. additionWhen the addition
  3. customchlorine gas was bubbled in at such a rate as
  4. customthe temperature below 10° C
  5. additionThe resulting mixture was poured into ice and concentrated hydrochloric acid
  6. extractionextracted with ethyl acetate several times
  7. washThe combined organic layers were washed with water
  8. dry with materialdried over anhydrous sodium sulfate
  9. customRemoving the solvent in the rotavap
  10. customyielded the crude product as a white solid
  11. customRecrystalization from acetone/water

Sources & evidence

ORD record
ord-bab1032a2d7b4faca934aa5ca93f69b5
Source dataset
uspto-grants-1994_04
Patent number
US05304572

Reaction notes

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