Facile synthesis and photo-Fries rearrangement of 2-benzoyl-4-benzoyloxyphenol leading to dibenzoyldihydroxybenzene derivatives

We prepared 2-benzoyl-4-benzoyloxyphenol 1 in 93% yield by reacting 1,4-dimethoxybenzene with benzoyl chloride in the presence of aluminium chloride. Irradiation of 1 with 254 mercury lamps provided 2,5-dibenzoyl-1,4-dihydroxybenzene 4, 2,3-dibenzoyl-1,4-dihydroxybenzene 5, and 2-benzoyl-1,4-dihydroxybenzene 6 with 19, 48, and 17% yields, respectively. The structure of the compound 4 was confirmed by single crystal X-ray analysis. Photo-Fries reaction of 1,4-dibenzoyloxybenzene 7 was also re-examined. The reported mp and 1H NMR data of 1 and 4 were corrected.