Identification of urinary metabolites of human subjects acutely poisoned by p-chloronitrobenzene.

1. Urinary metabolites from human subjects acutely poisoned with p-chloro-nitrobenzene (p-CNB) were identified by g.l.c.-mass spectrometry. 2. Eight substances, namely, a very large amount of N-acetyl-S-(4-nitrophenyl)-L-cysteine, relatively large quantities of p-chloroaniline, 2-chloro-5-nitrophenol and p-chloroformanilide produced by pyrolysis of a substance originating from p-CNB, small amounts of 2-amino-5-chlorophenol and 2,4-dichloroaniline, and traces of p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide, were detected in urine samples. 3. All of the absorbed p-CNB was metabolized prior to excretion, as the parent compound was not found in urine. 4. N-Acetylated metabolites of p-chloroaniline and 2-amino-5-chlorophenol, resulting from p-CNB by metabolism, were found in only one of eight individuals indicating that this pathway is weak or may be absent in some humans. 5. A scheme for the pattern of metabolic pathways of p-CNB is proposed, and chlorination was considered to be a possible novel metabolic pathway.