Sulfamethazine Related Compound B – (Mixture containing about 49% of 4-Amino-2-chloro-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide and about 48% of 4-Amino-3-chloro-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide)