O-Cresol → 2,3-Dihydro-5-hydroxy-6-methyl-1H-inden-1-one

HRID 1352198Notes

Reaction equation

HRID 1352198 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[C:5]1([CH3:12])[C:10]([OH:11])=[CH:9][CH:8]=[CH:7][CH:6]=1.S(=O)(=O)(O)O>C(Cl)Cl.O>[OH:11][C:10]1[CH:9]=[C:8]2[C:7](=[CH:6][C:5]=1[CH3:12])[C:10](=[O:11])[CH2:9][CH2:8]2

Participants

6

Reactant 3

HCID 335O-CresolHCID 1118Sulfuric AcidHCID 6451240Aluminum(III) Chloride

Product 1

HCID 211000362,3-Dihydro-5-hydroxy-6-methyl-1H-inden-1-oneYield 31.3%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

To a stirred suspension of aluminum chloride (3.0 g, 22.2 mmol) and o-cresol (2.0 g, 18.5 mmol) in methylene chloride (10 mL) was added 4-chloropropionyl chloride (2.0 mL, 20.4 mmol). After stirring overnight at rt, the reaction was quenched by the addition of methanol followed by 2N hydrochloric acid. The product was extracted in methylene chloride (3×30 mL), dried over magnesium sulfate and concentrated in vacuo to give a colorless oil. This oil was treated with concentrated sulfuric acid (10 mL) at 90° C. for 1 h, diluted with water (50 mL) and the product extracted into methylene chloride (3×30 mL). The combined organics were dried over magnesium sulfate and concentrated in vacuo. Silica gel chromatography eluting with 33% ethyl acetate/hexanes gave 0.47 g of the title compound: 1H NMR (500 MHz, CDCl3): δ 7.56 (s, 1H), 6.81 (s, 1H), 5.36 (s, 1H, OH), 3.04 (t, J=5.9 Hz, 2H), 2.65 (t, J=5.8 Hz, 2H), 2.28 (s, 3H)

Workup

  1. customthe reaction was quenched by the addition of methanol
  2. extractionThe product was extracted in methylene chloride (3×30 mL)
  3. dry with materialdried over magnesium sulfate
  4. concentrationconcentrated in vacuo
  5. customto give a colorless oil
  6. extractionthe product extracted into methylene chloride (3×30 mL)
  7. dry with materialThe combined organics were dried over magnesium sulfate
  8. concentrationconcentrated in vacuo
  9. washSilica gel chromatography eluting with 33% ethyl acetate/hexanes

Sources & evidence

ORD record
ord-3cd284ce7ed74474982f04244a1384e3
Source dataset
uspto-grants-2007_05
Patent number
US07220734B2

Reaction notes

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