Potassium Carbonate → 3,5-Dihydroxybenzoic Acid

HRID 2246803Notes

Reaction equation

HRID 2246803 reaction equation
C([O:3][C:4](=[O:13])[C:5]1[CH:10]=[C:9]([OH:11])[CH:8]=[C:7]([OH:12])[CH:6]=1)C.C([O-])([O-])=O.[K+].[K+].C(I)CCCCCCC>CC(C)=O.C1OCCOCCOCCOCCOCCOC1>[OH:11][C:9]1[CH:10]=[C:5]([CH:6]=[C:7]([OH:12])[CH:8]=1)[C:4]([OH:13])=[O:3]

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 123801-IodooctaneHCID 20098Benzoic acid, 3,5-dihydroxy-, ethyl ester

Product 1

HCID 74243,5-Dihydroxybenzoic AcidYield 62.7%

Reagents, catalysts & solvents 2

HCID 2855718-Crown-6CatalystHCID 180AcetoneSolvent

Procedure

Ethyl-3,5-dihydroxybenzoate 1a (27.3 g, 150 mmol) was dissolved in acetone (750 mL). To this solution were added K2CO3 (20.7 g, 150 mmol) and 18-Crown-6 (1.9 g, 7.5 mmol) and stirred for 5 min. To this mixture, C8H17I (21.7 mL, 120 mmol) was added and stirred to reflux for 7 h. The reaction mixture was then cooled to room temperature and the solvent was evaporated to dryness. To this residue, water and ethyl acetate were added and stirred for 30 min. The organic layer was separated and aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with water and brine solution. The organic layer was evaporated to dry ness and purified by silica gel column chromatography (3-4% ethyl acetate in dichloromethane) to afford 14.5 g (33% yield) of 4. The major by-product of this reaction is the compound, where two octyl groups are added to the two phenolic groups of compound 1a. 1H NMR (400 MHz, CDCl3) δ 7.14 (s, 2H), 6.6 (t, J=2.2 Hz, 1H), 5.32 (s, 1H), 4.35 (q, J=7.2 Hz, 2H), 3.95 (t, J=6.6 Hz, 2H), 1.80-1.73 (quintet, 2H), 1.46-1.28 (m, 13H), 0.88 (t, J=6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 166.8, 160.3, 156.8, 132.0, 109.0, 107.8, 106.9, 68.3, 61.3, 31.7, 29.3, 29.2, 29.1, 25.9, 22.6, 14.2, 14.0; GC/MS (m/z, r.i): 294 (M+, 68), 249 (12), 182 (100), 167 (8), 137 (25), 110 (12), 69 (12), 57 (8).

Workup

  1. stirringstirred
  2. temperatureto reflux for 7 h
  3. customthe solvent was evaporated to dryness
  4. additionTo this residue, water and ethyl acetate were added
  5. stirringstirred for 30 min
  6. customThe organic layer was separated
  7. extractionaqueous layer was extracted with ethyl acetate
  8. washThe combined organic layer was washed with water and brine solution
  9. customThe organic layer was evaporated
  10. customto dry ness
  11. custompurified by silica gel column chromatography (3-4% ethyl acetate in dichloromethane)

Sources & evidence

ORD record
ord-91dcb296677d4a299c62f0a8ac6c44cf
Source dataset
uspto-grants-2010_03
Patent number
US07687600B2

Reaction notes

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