Hydrochloric Acid → 4-(Difluoromethoxy)-3-hydroxybenzaldehyde

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Reaction Steps

3,4-Dihydroxybenzaldehyde (20 g, 145 mmol), chlorodifluoroacetic acid sodium salt (55.19 g, 362 mmol) and sodium hydroxide (5.50 g, 138 mmol) were stirred in DMF (1200 mL) at 55° C. under nitrogen for 16 hours. The pH was adjusted to 1.0 by the addition of 10% aqueous HCl followed by extraction with ethyl acetate (3×500 mL). The combined extracts were evaporated under vacuum. The residue was purified on silica gel using a 10-20% ethyl acetate/hexane gradient. 4-difluoromethoxy-3-hydroxybenzaldehyde was isolated in 24% yield (6.62 g). 1H NMR (CDCl3, 400 MHz) δ 6.1 (br s, 1H), 6.48-6.85 (t, 1H OCHF2), 7.26 (d, 1H), 7.44 (d, 1H), 7.55 (s, 1H), 9.91 (s, 1H).

Provenance & Evidence