Triazine reductions

It has already been mentioned that the degradation of s-triazine herbicides such as atrazinc in soil can be described by two reaction types only, hydrolysis and reductive dealkylation (see Figure 10.3-8). Application oF these two reaction types to a specific s-triazinc compound such as atrazinc provides the reaction network shown in Figure 10,3-12. This can also be vcriFicd by running this example on h ttp //www2,chemie,uni-erlangen.de/semces/eros/,... 

SnCl2 reduction produced the 4-hydrazinoisoxazole (243). In ethanol the diazonium salt reacted with the 4-aminoisoxazole to produce the linear triazine (244) (Scheme 85). Diazoisoxazoles can also be treated with KI or H20/urea to produce the 4-iodo or 4-hydroxy derivatives (63AHC(2)365). These Sandmeyer reactions have been extended to a variety of isoxazole systems (77JMC934, 63AHC(2)365). 

Attempts to prepare this substance by reduction of dioxotetrahydro-1,3,5-triazine with sodium amalgam,hydroiodic acid, or tin in acetic acid, were accompanied by hydrolytic cleavage of the ring. Only... 

The first systematic theoretical study on dihydro-1,2,4-triazines was recently carried out (98JOC5824) the stabilities of all the possible unsubstituted dihydro-1,2,4-triazines were calculated using various theoretical methods, all reliable calculation methods consistently show that the 2,5-dihydro isomer 98 is the most stable. This is in perfect agreement with the experimental observations all the synthetic methods used for the preparation of dihydro-1,2,4-triazines result in 2,5-dihydro isomer 98, provided the structures of the reactants and the reaction mechanism allow its formation. Thus, although Metze and Scherowsky (59CB2481) claimed the formation of 1,2-dihydro-1,2,4-triazine 92 (R = = Ph) in the reduction... 

The NH2 groups can be diazotized and reduced in the presence of thiosulphates and different metal ions. The effect of some metal ions, namely Fe ", Sn, Cu +, and Co on the graft yield of cotton modified with aryl diazonium groups via its reaction with 2,4-dichloro-6-(p-nitroaniline)-5-triazine in the presence of alkali and followed by reduction of nitro group was studied [4]. 

The reduction of the moisture absorption of cellulose fibers and their composites treated with triazine de-rivates is explained by [51,52] ... 

The Mitsunobu reaction was applied to the synthesis of pyrrolo[l,2-d [, 2,4]triazines from pyrrole derivative 71. Thus reduction of 71 gave alcohol 72, which on treatment with diethylazodicarboxylate and triphenyl phosphine gave 74 via the open chain intermediate 73. Hydrolysis of 74 gave 75 (84AG517) (Scheme 18). 

Under conditions of oxygen limitation, strains of Morganella morganii and Providencia rettgeri degraded hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) after initial reduction to the nitroso compounds (Kitts et al. 1994). 

RDX and its partial reduction product hexahydro-l-nitroso-3,5-dinitro-l,3,5-triazine were degraded by K. pneumoniae to methylenedinitramine, and then to CHjO and methanol, while abiotic reactions produced NjO (Zhao et al. 2002). 

The use of collision-induced dissociation (CID) and MS/MS techniques in conjunction with the API interfaces has dramatically impacted the fleld of environmental analysis. These techniques are now preferred for the determination of triazine compounds in water, soil, crops, etc., owing to the significant improvements in selectivity obtained via the monitoring of precursor-product ion pairs and increased sensitivity due to the reduction of chemical noise. 

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