Nitrogen/group 15 reactions nitro compound substrates

The catalytic effect of aromatic nitro groups in the substrate and product or in an added inert nitro compound (e.g., m-dinitrobenzene in 18) has been observed in the reaction of 2,4-dinitrochlorobenzene with an amine in chloroform. Hydrogen bonding to benzil or to dimethyl sulfone and sulfoxide also provided catalysis. It is clear that the type of catalysis of proton transfer shown in structure 18 will be more effective when hydrogen bonding is to an azine-nitrogen. 

Nitration of phenols by peroxidases can occur through two different mechanisms. The reaction requires phenol, nitrite, and hydrogen peroxide. In the principal mechanisms, compound I and compound II are formed. Upon one-electron oxidation of the substrates, phenoxy radical and nitrogen dioxide are produced. Coupling of these species gives the nitrophenol derivatives, where the nitro group is in the ortho or para position with respect to the phenol hydroxyl group. This reaction will be described in more detail in Sect. 6.1.5. 

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