Preparation by total demethylation of 4-methoxyphenyl 4-methoxybenzyl ketone (4,4′-dimethoxydeoxybenzoin),
? with refluxing pyridinium chloride (4 equiv) for 1 h (80–85%);
? with boiling a mixture of 50% aqueous hydriodic acid and phenol for 30 min (94%);
? with hydriodic acid (d = 1.7) in acetic acid at 135–140° for 10 min (quantitative yield);
? with aluminium chloride in refluxing benzene for 1.5 h (25%).
