4,4,5,7-Tetramethylchroman-2-one → 2-(4-Hydroxy-2-methylbutan-2-yl)-3,5-dimethylphenol

HRID 884012Notes

Reaction equation

HRID 884012 reaction equation
[CH3:1][C:2]1([CH3:15])[C:11]2[C:6](=[CH:7][C:8]([CH3:13])=[CH:9][C:10]=2[CH3:12])[O:5][C:4](=[O:14])[CH2:3]1.[H-].[Al+3].[Li+].[H-].[H-].[H-]>O1CCCC1>[OH:14][CH2:4][CH2:3][C:2]([C:11]1[C:10]([CH3:12])=[CH:9][C:8]([CH3:13])=[CH:7][C:6]=1[OH:5])([CH3:15])[CH3:1]

Participants

4

Reactant 2

HCID 6051634,4,5,7-Tetramethylchroman-2-oneHCID 21226445Aluminium lithium hydride

Product 1

HCID 146976962-(4-Hydroxy-2-methylbutan-2-yl)-3,5-dimethylphenolYield 72%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

The product of Example 94A (4.00 g, 0.0196 mol) in tetrahydrofuran (75 mL) was added dropwise to a solution of lithium aluminum hydride (1.0 M in tetrahydrofuran, 20.6 mL, 0.0206 mol) in tetrahydrofuran (105 mL) at room temperature over a period of 30 minutes then stirred an additional one hour at ambient temperature. The stirred reaction was quenched by dropwise addition of saturated aqueous ammonium chloride (5 mL) after 15 minutes, the precipitate was removed by vacuum filtration. The filtrate was concentrated by rotary evaporation and the residue purified by silica gel flash chromatography eluting with 4:96 methanol/methylene chloride to afford the title compound as a white solid (2.94 g, 0.014 mol, 72%). 1H NMR (300 MHz, DMSO-D6) δ ppm 1.44 (s, 6 H) 2.00-2.07 (m, 2 H) 2.08 (s, 3 H) 2.36 (s, 3 H) 3.11-3.28 (m, 2 H) 4.09 (t, J=4.78 Hz, 1 H) 6.29 (s, 1 H) 6.42 (s, 1 H) 8.95 (s, 1 H). MS (ESI+) m/z 209 (M+H)+, 226 (M+NH4)+.

Workup

  1. customThe stirred reaction
  2. customwas quenched by dropwise addition of saturated aqueous ammonium chloride (5 mL) after 15 minutes
  3. customthe precipitate was removed by vacuum filtration
  4. concentrationThe filtrate was concentrated by rotary evaporation
  5. customthe residue purified by silica gel flash chromatography
  6. washeluting with 4:96 methanol/methylene chloride

Sources & evidence

ORD record
ord-78692e92b27840a4a5b34e911f9e410c
Source dataset
uspto-grants-2012_08
Patent number
US08236950B2

Reaction notes

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