4-Hydroxybenzoic Acid → 4-[(tert-Butyldimethylsilyl)oxy]benzoic acid

Participants

Reaction Steps

4-Hydroxybenzoic acid (4.009 g, 28.96 mmol) and tert-butyldimethylsilyl chloride (9.984 g, 66.24 mmol) were dissolved in dry N,N-dimethylformamide (21 ml) containing imidazole (8.653 g, 127.1 mmol). Upon stirring for 10 hours under argon, the reaction mixture was shaken with diethyl ether (130 ml) and water (130 ml). The organic portion was washed with water (60 ml×2). The crude product resulting from evaporating to dryness was dissolved in tetrahydrofuran (32 ml). Methanol (96 ml) and a solution of potassium carbonate (6.40 g, 46.31 mmol) in water (50 ml) were added. The mixture was then stirred for 1 hour. The volume was reduced by half by evaporation before adding a saturated brine (96 ml) followed by acidification with 1M KHSO4. The aqueous portion was washed times with diethyl ether (100 ml×3), and the organic portion was evaporated to dryness. Recrystallization from a mixed solvent of water (200 ml), ethanol (75 ml) and acetone (20 ml) yielded (o) (4.61 g, 63%). Proton-NMR spectral data (acetone-d6), δ (ppm): 0.10 (s, Si(CH3)2, 6H), 1.02 (s, Si(C(CH3)3, 9H), 6.99 (d, aromatic, 2H), 7.95 (d, aromatic, 2H)

Provenance & Evidence