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

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)

1. washThe organic portion was washed with water (60 ml×2)
2. customThe crude product resulting
3. customfrom evaporating to dryness
4. dissolutionwas dissolved in tetrahydrofuran (32 ml)
5. stirringThe mixture was then stirred for 1 hour
6. customThe volume was reduced by half by evaporation
7. additionbefore adding a saturated brine (96 ml)
8. washThe aqueous portion was washed times with diethyl ether (100 ml×3)
9. customthe organic portion was evaporated to dryness
10. customRecrystallization from a mixed solvent of water (200 ml), ethanol (75 ml) and acetone (20 ml)

ORD record

ord-a71a2e5e80cc4a4c908d9fae086aba84

Source dataset

uspto-grants-2004_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06730242B2