2.4- Diamino-6-nitrotoluene formation

Various modern products may serve as sources for trace amounts of PAA. The origins, known hazards, release restrictions and environmental fate of PAA derived from azo dyes have been reviewed2. The metabolism of nitroarenes is closely linked to that of aromatic amines, as shown in a simplified way in equation 369. Gloeophyllum trabeum cultures spiked with TNT show formation of nitroaromatic amines such as 2-ami no-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene. Also, autoxi-dation of the methyl group of TNT or its metabolites may take part in the degradation process, as shown by the presence of Schiff bases and oligomeric and polymeric species detection and determination of the analytes after LLE and concentration were by HPLC-UVD or GC-MS70. 

The subsequent reduction of the resulting aminodinitrotoluene with almost exclusive formation of 2,4-diamino-6-nitrotoluene is mediated by several mainly facultatively or strictly anaerobic bacteria, as described by Naumova et al. (34) and McCormick et al. (32). Moreover, Naumova et al. (34) observed that the further reduction of aminodinitrotoluene to diaminonitrotoluene was enhanced under conditions of nitrate respiration as compared to aerobic conditions. 

The further conversion of 2,4-diamino-6-nitrotoluene to triaminotoluene seems to be confined to anaerobic microorganisms. Funk et al. (15) described the formation of triami-... 

The experiment was then repeated with chemically synthesized 4-formamido-2,6-dinitrotoluene instead of 4-amino-2,6-dinitrotoluene. The reduction product isolated was identified as 2-amino-4-formamido-6-nitrotoluene. Using this compound as substrate, very slow formation of 2,4-diamino-6-nitrotoluene (detectable only after 96 h of incubation) could be observed. The sequence of reactions that follows 4-amino-2,6-dinitrotoluene is depicted in Figure 5. We could not obtain any evidence for a direct reduction of 4-amino-2,6-dinitrotoluene to 2,4-diamino-6-nitrotoluene. 

The identification of 2-amino-4-formamido-6-nitrotoluene as a substrate of the lignin peroxidase raises questions about the role of 2,4-diamino-6-nitrotoluene. Its formation from 2-amino-4-formamido-6-nitrotoluene under non-ligninolytic conditions can be expected, since acylation reactions (formylation and acetylation) of aromatic amino goups are clearly reversible (29). 

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