2,4-Dihydroxybenzaldehyde → 5-chloro-2,4-dihydroxybenzaldehyde

Participants

Reaction Conditions

Reaction Steps

Sodium hypochlorite (75 mL, 0.055 mol) and piperidine (4.68 g, 0.055 mol) were cooled to 0° C., combined cautiously and added dropwise over 2 h to a solution of 2,4,-dihydroxybenzaldehyde (6.91 g, 0.05 mol) in 50% aqueous sulfuric acid (150 mL) while cooling to 0° C. After three additional hours, the precipitate was collected via filtration in quantitative yield. 1H NMR indicates that it is about 65% 5-chloro-2,4-dihdroxybenzaldehyde, with the balance being 3-chloro-2,4-dihdroxybenzaldehyde. The product can be purified via column chromatography and/or repeated recrystallizations from toluene. However, the 3-chloro-2,4-dihdroxybenzaldehyde does not react in the next reaction, so the product was used without further purification.

Provenance & Evidence