(Z)-6-{[1,3-Dihydroxy-2-(hydroxymethyl)propan-2-yliminio]methyl}-2-ethoxyphenolate, (Z)-6-{[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yliminio]methyl}-4-nitratocyclohexa-2,4-dienone monohydrate and (R,E)-2-[(1-hydroxybutan-2-ylimino)methyl]phenol.