Phosphoric Acid → 4-Cyclopentylbenzene-1,3-diol--water (1/1)

HRID 1391640Notes

Reaction equation

HRID 1391640 reaction equation
[C:1]1([CH:8]=[CH:7][CH:6]=[C:4]([OH:5])[CH:3]=1)[OH:2].[CH:9]1(O)[CH2:13][CH2:12][CH2:11][CH2:10]1.OP(O)(O)=O>O.C1(C)C=CC=CC=1>[OH2:2].[CH:9]1([C:6]2[CH:7]=[CH:8][C:1]([OH:2])=[CH:3][C:4]=2[OH:5])[CH2:13][CH2:12][CH2:11][CH2:10]1

Participants

6

Reactant 3

HCID 1004Phosphoric AcidHCID 5054ResorcinolHCID 7298Cyclopentanol

Product 1

HCID 692640144-Cyclopentylbenzene-1,3-diol--water (1/1)Yield 104.5%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1140TolueneSolvent

Conditions

Temperature
107.5 °C

Procedure

To a N2 purged pressure reactor is charged resorcinol (44.0 g, 0.40 mol), cyclopentanol (44 mL, 0.49 mol) and 85% aqueous H3PO4 (55 mL, 0.80 mol). The slurry is heated to 95-120° C. for 6-18 hours. The pink reaction mixture is cooled to ˜70° C. and diluted with water (50 mL) and toluene (200 mL). The layers are allowed to separate at 60±5° C. The bottom orange aqueous layer is cut away. The remaining pink organic layer is extracted with 2×50 mL water at 60±5° C. and then stirred with carbon (5 g) at 60±5° C. for 1-2 hours. The slurry is filtered hot through Supercel, rinsing the cake with hot toluene (50 mL). The orange filtrate is diluted with 5 mL water and allowed to cool to ˜30° C. at which time the product crystallizes. The slurry is cooled to 0-5° C. and the product collected, washed with cold toluene (40 mL) and pulled dry on the funnel to afford 41 g of 4-cyclopentyl resorcinol monohydrate as a white to pale pink solid (≧98% area by HPLC). The material can be recrystallized if desired from hot toluene (5 mL/g) and carbon (10% by weight) filtering through Supercel and/or silica gel to the Form I polymorph of 4-cyclopentyl resorcinol afford as a white solid (≧99.7% by HPLC).

Workup

  1. customTo a N2 purged pressure reactor
  2. temperatureThe pink reaction mixture is cooled to ˜70° C.
  3. customto separate at 60±5° C
  4. extractionThe remaining pink organic layer is extracted with 2×50 mL water at 60±5° C.
  5. filtrationThe slurry is filtered hot through Supercel
  6. washrinsing the cake with hot toluene (50 mL)
  7. additionThe orange filtrate is diluted with 5 mL water
  8. temperatureto cool to ˜30° C. at which time the product
  9. customcrystallizes
  10. temperatureThe slurry is cooled to 0-5° C.
  11. customthe product collected
  12. washwashed with cold toluene (40 mL)
  13. custompulled dry on the funnel

Sources & evidence

ORD record
ord-beb564280c2541f3b2e9c60c4fc003d6
Source dataset
uspto-grants-2008_03
Patent number
US07338979B2

Reaction notes

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