Dimethyl Carbonate → Benzoic acid, 4-(allyloxy)-3,5-dimethyl-

HRID 1666586

Reaction equation

HRID 1666586 reaction equation
[CH2:1]([O:4][C:5]1[C:10]([CH3:11])=[CH:9][C:8](Br)=[CH:7][C:6]=1[CH3:13])[CH:2]=[CH2:3].[Li]CCCC.C[O:20][C:21](=O)[O:22]C>C1COCC1>[CH2:1]([O:4][C:5]1[C:10]([CH3:11])=[CH:9][C:8]([C:21]([OH:22])=[O:20])=[CH:7][C:6]=1[CH3:13])[CH:2]=[CH2:3]

Participants

5

Reactant 3

HCID 12021Dimethyl CarbonateHCID 6412705-Bromo-1,3-dimethyl-2-((prop-2-en-1-yl)oxy)benzeneHCID 178418339Butyllithium

Product 1

HCID 23581Benzoic acid, 4-(allyloxy)-3,5-dimethyl-

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of 2-allyloxy-5-bromo-1,3-dimethyl-benzene (23.6 g, 98.0 mmol) in THF (150 mL) is added at −75° C. a solution of n-BuLi (90 mL, 1.5 M in diethyl ether). The temperature remains at −75° C. The mixture is stirred for 30 min and then transferred via double-tip canula into a cooled (0° C.) solution of dimethylcarbonate (21.4 g, 238 mmol) in THF (90 mL). The mixture is stirred for 2 h at 0° C., then warmed to rt during 15 h. The solvent of the mixture is evaporated and re-evaporated with EtOH (200 mL) to remove most of the butylacetate side product. The mixture is taken up in 2 N aq. LiOH (150 mL) and EtOH (200 mL) and stirred at rt for 2 h then at 60° C. for 1 h. The EtOH is evaporated and the remaining mixture is diluted with 0.5 N aq. NaOH and extracted with diethyl ether (200 mL). The org. extract is washed with 1M aq. NaOH (5×50 mL) and the combined aq. washings are re-extracted with ether (100 mL). The aq. phase is acidified with 25% aq. HCl and extracted with DCM (5×50 mL). The combined org. extracts are dried over Na2SO4, filtered, evaporated and dried in vacuo at 60° C. for 15 h to give 4-allyloxy-3,5-dimethyl-benzoic acid (8.0) as a yellow-brown solid. LC-MS: tR=0.90 min.

Workup

  1. customremains at −75° C
  2. stirringThe mixture is stirred for 2 h at 0° C.
  3. customThe solvent of the mixture is evaporated
  4. customre-evaporated with EtOH (200 mL)
  5. customto remove most of the butylacetate side product
  6. stirringEtOH (200 mL) and stirred at rt for 2 h
  7. waitat 60° C. for 1 h
  8. customThe EtOH is evaporated
  9. additionthe remaining mixture is diluted with 0.5 N aq. NaOH
  10. extractionextracted with diethyl ether (200 mL)
  11. extractionextract
  12. washis washed with 1M aq. NaOH (5×50 mL)
  13. extractionthe combined aq. washings are re-extracted with ether (100 mL)
  14. extractionextracted with DCM (5×50 mL)
  15. dry with materialextracts are dried over Na2SO4
  16. filtrationfiltered
  17. customevaporated
  18. customdried in vacuo at 60° C. for 15 h

Sources & evidence

ORD record
ord-e618276846fa44a083f263485d74b284
Source dataset
uspto-grants-2011_10
Patent number
US08044076B2

Linked notes

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