Answer
Friedrich Mietzsch and Joseph Klarer were the chemists who synthesized the compound found active against Streptococcus pyogenes. They were working in the German chemical company IG Farben, and they were looking for a new antibiotic to treat bacterial infections. They found that a compound called Prontosil had antibacterial activity, and they were able to synthesize a new compound called Prontosil red that was more effective against Streptococcus pyogenes.