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 R 2 2(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).