1 : 1 molecular complexes of 4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (sulfamethazine) with indole-2-carboxylic acid and 2,4-dinitrobenzoic acid

The 1:1 molecular adducts of 4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenes ulfonamide (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 R-2(2)(8) graph set hydrogen-bonding interactions across the N(11)-H/N(17) site of Sulfamethazine. A comparison of the two distances between relevant non-hydrogen atoms in this configuration reveals that this association is n ot symmetrical. An average difference of 0.144 Angstrom is observed for sev en listed complexes of Sulfamethazine, five having been previously reported . This average difference compares with a value of 0.265 Angstrom for the s ame interaction seen in carboxylic acid adducts of 2-aminopyrimidine.