Hydrochloric Acid → 4,5-Dimethoxy-2-nitrophenol

Beteiligte Stoffe

Reaktionsschritte

To a solution of 4,5-dimethoxy-2-nitro-benzaldehyde (3.75 g, 14.2 mmol) in dichloromethane (75 mL) at 0° C. under a nitrogen atmosphere was added meta-chloroperoxybenzoic acid (75% purity, 4.90 g, 28.4 mmol), then trifluoroacetic acid (1.05 mL, 14.2 mmol). The reaction was stirred at room temperature for 18 h, then recooled to 0° C. Excess reagent was quenched with 5% sodium bisulfite solution and the precipitate was removed by filtration, washing with dichloromethane. The organic phase of the filtrate was washed with sodium bicarbonate and brine, was dried (sodium sulfate), and was evaporated to provide a yellow solid. This intermediate was suspended in methanol (50 mL), treated with 2N NaOH (16 mL, 32 mmol), and was stirred at room temperature for 1 h. The reaction was acidified with 1N HCl and was filtered, washing with methanol to provide 4,5-dimethoxy-2-nitro-phenol (2.00 g, 71% yield) as a bright yellow solid. 1H-NMR (CDCl3, 500 MHz) 11.0 (s, 1H), 7.39 (s, 1H), 6.48 (s, 1H), 3.90 (s, 3H), 3.83 (s, 3H) ppm; MS (FIA) 197.9 (M−H); HPLC (Method A) 3.357 min.

Herkunft & Nachweise