Thionyl Chloride → 5-Chloro-2-methoxy-4-methylbenzoyl chloride

HRID 1077275Notes

Reaction equation

HRID 1077275 reaction equation
S(Cl)([Cl:3])=O.[CH3:5][O:6][C:7]1[CH:15]=[C:14]([CH3:16])[C:13]([Cl:17])=[CH:12][C:8]=1[C:9](O)=[O:10]>>[CH3:5][O:6][C:7]1[CH:15]=[C:14]([CH3:16])[C:13]([Cl:17])=[CH:12][C:8]=1[C:9]([Cl:3])=[O:10]

Participants

3

Reactant 2

HCID 24386Thionyl Chloride2×HCID 186873865-Chloro-2-methoxy-4-methylbenzoic acid

Product 1

HCID 215361405-Chloro-2-methoxy-4-methylbenzoyl chlorideYield 233.4%

Conditions

Temperature
30 °C

Procedure

In a 500 ml flask equipped with a refrigerant, there are introduced 87 g of thionyl chloride and about 31 g of 2-methoxy-4-methyl-5-chlorobenzoic acid and the mixture is heated on a water bath at 30° C. Dissolution occurs almost immediately, followed by reprecipitation. Then 31 g of acid is added. There is obtained a very thick, rose-colored precipitate. 41 g of thionyl chloride are added and the mixture is heated at 50°-55° C. At the end of 3/4 of an hour at this temperature, if dissolution is not complete, heating is continued to dissolution (70°-75° C). The excess thionyl chloride is removed under vacuum. There are obtained 79 g (yield 99%) of 2-methoxy-4-methyl-5-chlorobenzoyl chloride (m.p. 106°-107° C).

Workup

  1. customIn a 500 ml flask equipped with a refrigerant, there
  2. dissolutionDissolution
  3. customfollowed by reprecipitation
  4. additionThen 31 g of acid is added
  5. customThere is obtained a very thick, rose-colored precipitate
  6. temperaturethe mixture is heated at 50°-55° C
  7. dissolutionAt the end of 3/4 of an hour at this temperature, if dissolution
  8. temperatureheating
  9. dissolutionis continued to dissolution (70°-75° C)
  10. customThe excess thionyl chloride is removed under vacuum

Sources & evidence

ORD record
ord-646f4153c7684baeb1e9b897255df783
Source dataset
uspto-grants-1976_05
Patent number
US03959477

Reaction notes

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