“…Thus, oxidation of 2,6-dimethyl-4-aminophenol with Ag 2 O in Et 2 O leads to a crimson dye with the spectrum δ (ppm) = 7.75 (s, 1H), 7.73 (s, 1H), 7.58 (s, 1H), 7.24 (s, 2H), 2.98 (s, 6H), 2.76 (s, 3H), 2.68 (s, 3H), which agrees well with that of the hydrazone 4-[2-(4-hydroxy-3,5-dimethylphenyl)hydrazone]-2,6-dimethyl-2,5-cyclohexadiene-1,4-dione. This is a dimer of the imine, whose diazo tautomer was reported in ref . The dye is stable in aqueous solution (crimson in acidic, blue in alkaline), but does not react with 2,6-dimethyl-4-aminophenol.…”