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4-Nitro-o-phenylenediamine is a direct-acting mutagen.
N 2562 (OTTO) 4-Nitro-o-phenylenediamine, 98% Cas 99-56-9 - used to study the in vitro activation of 4-nitro-o-phenylenediamine into a potent mutagen in Salmonella typhimurium strain TA98.