Diazomethane → 1-Methyl 2,6-dimethyl-1,4-benzenedicarboxylate

HRID 1058455Notes

Reaction equation

HRID 1058455 reaction equation
C[O:2][C:3]([C:5]1[CH:13]=[C:12]([CH3:14])[C:8]([C:9]([OH:11])=[O:10])=[C:7]([CH3:15])[CH:6]=1)=[O:4].[N+](=[CH2:18])=[N-].O.[OH-].[Li+]>CO.O>[CH3:15][C:7]1[CH:6]=[C:5]([CH:13]=[C:12]([CH3:14])[C:8]=1[C:9]([O:11][CH3:18])=[O:10])[C:3]([OH:2])=[O:4]

Participants

6

Reactant 3

HCID 9550DiazomethaneHCID 168937Lithium hydroxide, monohydrateHCID 3482914-(Methoxycarbonyl)-2,6-dimethylbenzoic acid

Product 1

HCID 158568511-Methyl 2,6-dimethyl-1,4-benzenedicarboxylate

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

A solution of 4-(methoxycarbonyl)-2,6-dimethylbenzoic acid (2.08 g: 10 mmol) in methanol (25 mL) is treated with ethereal diazomethane until the yellow color persists and the solution is left at room temperature overnight. The solution is concentrated in vacuo to remove the remaining diethyl ether, then tetrahydrofuran (25 mL) is added. The solution is stirred in an ice-water bath as a solution of lithium hydroxide monohydrate (0.462 g, 11 mmol) in water (25 mL) is added. After the cooling bath is removed, the reaction is allowed to proceed at room temperature overnight. The volatiles are removed under reduced pressure on a rotary evaporator (bath temperature <30° C.), then the concentrate is diluted with brine and extracted with dichloromethane to remove residual 2,6-dimethylterephthalic acid dimethyl ester. The aqueous phase is acidified to pH 2 using 3N hydrochloric acid (4 mL), then is extracted with dichloromethane (2×25 mL). The combined organic extracts are washed with brine, then are dried (MgSO4), filtered and evaporated in vacuo to yield 3,5-dimethyl-4-(methoxycarbonyl)benzoic acid.

Workup

  1. concentrationThe solution is concentrated in vacuo
  2. customto remove the remaining diethyl ether
  3. additiontetrahydrofuran (25 mL) is added
  4. additionis added
  5. customAfter the cooling bath is removed
  6. waitto proceed at room temperature overnight
  7. customThe volatiles are removed under reduced pressure on a rotary evaporator (bath temperature <30° C.)
  8. additionthe concentrate is diluted with brine
  9. extractionextracted with dichloromethane
  10. customto remove residual 2,6-dimethylterephthalic acid dimethyl ester
  11. extractionis extracted with dichloromethane (2×25 mL)
  12. washThe combined organic extracts are washed with brine
  13. dry with materialare dried (MgSO4)
  14. filtrationfiltered
  15. customevaporated in vacuo

Sources & evidence

ORD record
ord-a4889df77cfa4448a5052dc50e112a19
Source dataset
uspto-grants-2003_02
Patent number
US06515124B2

Reaction notes

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