2,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-carboxylic acid → 2,2,4,4-Tetramethyl-chroman-6-yl methanol

HRID 1440431Notes

Reaction equation

HRID 1440431 reaction equation
[CH3:1][C:2]1([CH3:17])[CH2:11][C:10]([CH3:13])([CH3:12])[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:14](O)=[O:15])[CH:8]=2)[O:3]1>C1COCC1>[CH3:1][C:2]1([CH3:17])[CH2:11][C:10]([CH3:12])([CH3:13])[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([CH2:14][OH:15])[CH:8]=2)[O:3]1

Participants

3

Reactant 1

HCID 157287092,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-carboxylic acid

Product 1

HCID 189835652,2,4,4-Tetramethyl-chroman-6-yl methanol

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of 2,2,4,4-tetramethylchroman 6-carboxylic acid (0.28 g, 1.2 mmol) in THF (5 ml) under N2 was added 1M of LiALH4 /THF (1.15 ml, 1.15 mmol). The reaction mixture was left at room temperature for overnight, followed by addition of ice-water to the reaction. The reaction mixture was extracted with ethyl acetate, the organic extracts were dried and concentrated to give 2,2,4,4-tetramethyl-chroman-6-yl methanol as a white solid. Without further purification, the alcohol was dissolved in CH2Cl2 (5 ml) and MnO2 (1.04 g, 12 mmol) was added. The resulting mixture was stirred at room temperature for 5 hours. After filtration, the resulting colorless clear solution was concentrated and purified by column chromatography (silica gel, 10% ethyl acetate in hexane) to give the title compound as a colorless oil (0.147 g, 57%). 1H NMR d 1.39 (d, 12H), 1.88 (s, 2H), 6.89 (d, J=8.4 Hz, 1H), 7.62 (dd, J1 =2.0 Hz, J2 =8.4 Hz, 1H), 7.85 (d, J=2.0 Hz, 1H), 9.86 (s, 1H).

Workup

  1. extractionThe reaction mixture was extracted with ethyl acetate
  2. customthe organic extracts were dried
  3. concentrationconcentrated

Sources & evidence

ORD record
ord-4b26c232c63b4a0394d2a9cd59ba6c8d
Source dataset
uspto-grants-1996_03
Patent number
US05498755

Reaction notes

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