Hydrochloric Acid → 2,4-Bis(benzyloxy)-5-bromobenzoic acid

HRID 41382Notes

Reaction equation

HRID 41382 reaction equation
[OH:1][C:2]1[CH:10]=[C:9]([OH:11])[C:8]([Br:12])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].C(=O)([O-])[O-].[K+].[K+].[CH2:19](Br)[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1.[OH-].[K+].Cl>CN(C=O)C.O.CO>[CH2:19]([O:1][C:2]1[CH:10]=[C:9]([O:11][CH2:4][C:3]2[CH:7]=[CH:8][CH:9]=[CH:10][CH:2]=2)[C:8]([Br:12])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5])[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1

Participants

9

Reactant 5

HCID 313Hydrochloric AcidHCID 7498Benzyl BromideHCID 11430Potassium CarbonateHCID 14797Potassium HydroxideHCID 818145-Bromo-2,4-dihydroxybenzoic acid

Product 1

HCID 469156382,4-Bis(benzyloxy)-5-bromobenzoic acidYield 56%

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolventHCID 6228DimethylformamideSolvent

Procedure

2,4-dihydroxy-5-bromobenzoic acid (5.16 g, 22.15 mmol) was dissolved in DMF (40 ml) and potassium carbonate (12.2 g) and benzyl bromide (8 ml) were sequentially added. The mixture was stirred at room temperature for 18 hours under nitrogen. An aqueous solution of potassium hydroxide (2 g) in water (25 ml) was then added, followed by methanol (50 ml) and the mixture heated to reflux with vigorous stirring for 24 hours. The mixture was then allowed to cool, was poured into 1N HCl (250 ml) and was then extracted with ether and then DCM. The combined organic layers were dried over magnesium sulphate and the solvent evaporated in vacuo. The resulting solid material was washed with P.E. and then Et2O (3×50 ml) to yield pure product (5.2 g, 56%). 1H NMR (MeOH-d4) 8.06 (1H, s), 7.51-7.30 (10H, m), 6.85 (1H, s), 5.22 (2H, s), 5.20 (2H, s). MS: [M+H]+ 413.

Workup

  1. temperaturethe mixture heated
  2. temperatureto reflux
  3. stirringwith vigorous stirring for 24 hours
  4. temperatureto cool
  5. extractionwas then extracted with ether
  6. dry with materialThe combined organic layers were dried over magnesium sulphate
  7. customthe solvent evaporated in vacuo
  8. washThe resulting solid material was washed with P.E

Sources & evidence

ORD record
ord-724ea89d6fce4f0c8662f1c61cca9e57
Source dataset
uspto-grants-2013_09
Patent number
US08530469B2

Reaction notes

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