Acetone Cyanohydrin → 2-(4-Methylbenzoyl)-4,4-dimethyl-1,3-cyclohexanedione

HRID 393913Notes

Reaction equation

HRID 393913 reaction equation
[CH3:1][C:2]1[CH:18]=[CH:17][C:5]([C:6]([O:8]C2C=CC(C#N)=CC=2)=O)=[CH:4][CH:3]=1.[CH3:19][C:20]1([CH3:28])[CH2:25][CH2:24][C:23](=[O:26])[CH2:22][C:21]1=[O:27].C(N(CC)CC)C.CC(C)(O)C#N>C(#N)C>[CH3:1][C:2]1[CH:3]=[CH:4][C:5]([C:6]([CH:22]2[C:21](=[O:27])[C:20]([CH3:28])([CH3:19])[CH2:25][CH2:24][C:23]2=[O:26])=[O:8])=[CH:17][CH:18]=1

Participants

6

Reactant 4

HCID 6406Acetone CyanohydrinHCID 8471TriethylamineHCID 1363601,3-Cyclohexanedione, 4,4-dimethyl-HCID 5325074-Cyanophenyl 4-methylbenzoate

Product 1

HCID 226483322-(4-Methylbenzoyl)-4,4-dimethyl-1,3-cyclohexanedione

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A 50-mL single neck round bottom flask was charged with 4-cyanophenyl 4-methylbenzoate (2.65 g, 11.2 mmol), 4,4-dimethyl-1,3-cyclohexanedione (2.10 g, 15 mmol) and acetonitrile (15 mL). Then triethylamine (2.5 g, 25 mmol) and acetone cyanohydrin (0.14 mL, 1.5 mmol) were added and the mixture was refluxed for 6 hours. Volatiles were stripped from the reaction mixture and the residue was partitioned between diethyl ether (100 mL) and water (50 mL). The organic layer was extracted with saturated aqueous sodium bicarbonate (30 mL), then water (10 mL), then brine (10 mL). All aqueous layers were combined and 1N hydrochloric acid was added to pH 1. The resulting oil was extracted into dichloromethane (30 mL, 2×15 mL). The dichloromethane layers were combined, dried over magnesium sulfate, filtered and stripped to a brown oil (3.57 g). The crude product was chromatographed on silica gel (200 g), eluting with hexanes-ethyl acetate (4:1). Fractions containing pure product were concentrated to a yellow oil (2.08 g), which was crystallized from hexanes to afford the title compound as off-white crystals, 1.35 g (46.8%), m.p. 78-79° C. 1H NMR (DMSO-d6): δ 1.08 (s, 6), 1.84 (m, 2), 2.36 (s, 3), 2.61 (m, 2), 7.26 (d, 2), 7.60 (d, 2).

Workup

  1. temperaturethe mixture was refluxed for 6 hours
  2. customthe residue was partitioned between diethyl ether (100 mL) and water (50 mL)
  3. extractionThe organic layer was extracted with saturated aqueous sodium bicarbonate (30 mL)
  4. addition1N hydrochloric acid was added to pH 1
  5. extractionThe resulting oil was extracted into dichloromethane (30 mL, 2×15 mL)
  6. dry with materialdried over magnesium sulfate
  7. filtrationfiltered
  8. customThe crude product was chromatographed on silica gel (200 g)
  9. washeluting with hexanes-ethyl acetate (4:1)
  10. additionFractions containing pure product
  11. concentrationwere concentrated to a yellow oil (2.08 g), which
  12. customwas crystallized from hexanes

Sources & evidence

ORD record
ord-bb99f56dcf444e338b949f5b58ade192
Source dataset
uspto-grants-2004_10
Patent number
US06809206B2

Reaction notes

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