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

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Reaction Steps

The product of Example 436A (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)+.

Provenance & Evidence