2-(4-Aminobenzenesulfonamido)-4,6-dimethylpyrimidin-1-ium 2-carboxy-4,6-dinitrophenolate

Abstract

In the structure of the phenolate salt of the sulfa drug sulfamethazine with 3,5-dinitrosalicylic acid, C12H15N4O2S+·C7H3N2O7−, the dihedral angle between the pyrimidine and benzene rings of the cation is 59.70 (17)°. In the crystal, cation–anion hydrogen-bonding interactions involving pyrimidine–carboxy N+—H...O and amine–carboxy N—H...O pairs give a cyclic R22(8) motif while secondary N—H...O hydrogen bonds between the aniline group and both sulfone and nitro O-atom acceptors give a two-dimensional structure extending in (001).