METAL DERIVATIVES OF ISOHUMULONE: ADDENDUM: PREPARATION OF ISOHUMULONE A

Compounds of characteristic properties are formed between isohumulone and various metals. The compounds appear to contain the equivalent of one molecule of isohumulone for each electrovalency of the metal concerned, with the isohumulone moiety in the enol form and the metal bound through the triketo-methine group, though cations (ferric, cupric) which can exert an oxidizing effect may react differently with isohumulone from those which can not. Combination between isohumulone and heavy metals probably occurs readily in beer, isohumulone A is more conveniently prepared by boiling with N/10 sodium carbonate solution than with N/15 sodium hydroxide.