Nitrogen-containing compounds nitro group reduction

The types of nitrogen-containing compounds that are most frequently involved in reductive biotransformation are those containing nitro, azo, and N-oxide functional groups. Similar enzymes are involved that are generally located in the endoplasmic reticulum or cytosol of the liver or in the intestinal microflora. Complete reduction of a nitro compound to the primary amine involves a six-electron transfer and proceeds through nitroso and hydroxylamine intermediates [Eq. (16)]. 

The antidepressant agent tampramine (44-6) can be viewed as a distant analogue of imipramine that contains an extra benzene ring and two additional nitrogen atoms. The preparation of this compound starts by Ullman coupling of chloropyridine (44-1) with the aminobenzophenone (44-2) more frequently used for benzodiazepine syntheses. Reduction of the nitro group in the product (44-3) leads to a diamine (44-4) that readily cyclizes to form the pyridodiazepine (44-5). Alkylation of the anion from the treatment of this with sodium hydride with 3-chloro-1 -dimethylaminopropane affords tampramine (44-6) [44]. 

Generalized reductions of nitrogen-containing groups are illustrated in Fig. 15. These include the reduction of aromatic nitro and azo compounds as well as... 

Unstable amines and amines containing functional groups unstable under acidic reduction conditions can be obtained directly as the hydrochlorides by hydrogenation of nitriles, nitro compounds, azides, or oximes in the presence of chloroform A new type of basic amide hydrolysis, characterized by alkyl-nitrogen fission, has been reported Semisynthetic cephalosporins have been prepared via a novel acyl exchange reaction... 

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