Other instances have been reported of the loss of a methyl group from a substituted benzoquinone on treatment with an amine, though not, so far as we are aware, on treatment with monomethylamine. Hoffman (Ber., 1901, 34, 1558) showed that when an alcoholic solution of dibromothymoquinone is treated with p-toluidine, 3: 6-dibromo-4- ptoluidinoisopropyl-2: 5-benzoquinone is formed. A similar compound was obtained with ...