Preparation by condensation of benzotrichloride with p-cresol,
? in the presence of aluminium chloride in carbon disulfide for 2 h (75%). The 6,12-diphenyl-2,8-dimethyl-6,12-epoxy-6H,12H-dibenzo[b,f] dioxocin, an intermediate compound, was also formed under these conditions (29%). This “dioxocin”, by hydrolysis with concentrated sulfuric acid at r.t., gave the expected ketone (91%);
? in the presence of aqueous sodium hydroxide in a water bath for 4 h (33%) or in 32–40% aqueous sodium hydroxide at 70–80° (67%).
