N,N-Dimethyl-3,4-dimethoxyphenethylamine has been isolated for the first time as a natural product from Echinocereus merkeri Hildm. N-Methyl-3,4-dimethoxyphenethylamine, 3,4 dimethoxyphenethylamine, 3-methoxytyramine, and hordenine were also identified in this species together with the tetrahydroisoquinoline alkaloid salsoline; The ring opening of four cyclic salicylamides to their phenolic analogs is described. Compounds in which a basic group is separated from the amide nitrogen by a three-carbon chain were found to undergo this reaction considerably more slowly than compounds with a two-carbon chain. Ring opening was shown to be pH dependent and is base-catalyzed.