1 : 1 Molecular Complexes of 4-Amino-N-(4,6-dimethylpyrimidin-2-yl)benzene-sulfonamide (Sulfamethazine) with Indole-2-carboxylic Acid and 2,4-Dinitrobenzoic Acid

Abstract

The 1 : 1 molecular adducts of 4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (Sulfamethazine) with respectively indole-2-carboxylic acid (1) and 2,4-dinitrobenzoic acid (2) have been prepared and their X-ray crystal structures determined. The acid groups in both structures form associative R²₂ (8) graph set hydrogen-bonding interactions across the N(11)–H/N(17) site of Sulfamethazine. Acomparison of the two distances between relevant non-hydrogen atoms in this configuration reveals that this association is not symmetrical. An average difference of 0.144 Å is observed for seven listed complexes of Sulfamethazine, five having been previously reported. This average difference compares with a value of 0.265 Å for the same interaction seen in carboxylic acid adducts of 2-aminopyrimidine.