Hydrochloric Acid → (3,5-dimethyl-1-phenyl-1H-pyrazol-4-yl)-acetaldehyde

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 4-(2-methoxy-vinyl)-3,5-dimethyl-1-phenyl-1H-pyrazole (7.09 g, 31.1 mmol) in 100 mL isopropanol-water (1:1 v/v) was added p-toluenesulfonic acid monohydrate (1.5 g, 7.76 mmol). After the reaction was heated at 60° C. for 16 h, 1.9 mL concentrated hydrochloric acid was added and the reaction mixture was heated at 60° C. for 20 h. The organic solvent was removed in vacuo and the remaining aqueous suspension was neutralized with an aqueous sodium bicarbonate solution and extracted several times with a dichloromethane-ethyl acetate mixture. The combined organic extracts were dried over magnesium sulfate and concentrated in vacuo to produce a residue, which was purified via silica gel column chromatography (0-50% ethyl acetate in heptane) to give the title compound as a yellow solid (4.02 g, 18.8 mmol, 60% yield).

Provenance & Evidence