Simple Aromatic Nitro Compounds

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Aliphatic methyl ketones (CH3C(0)CH3) Simple aromatic nitro compounds (NO+CO) Straight-chain mercaptans Thiocyanates and isothiocyanates... 

Simple Aromatic Nitro Compounds Dinitrotoluene Nitrobenzene... 

Dimethylhydrazine, N,N Unsymmetrical Dimethylhydrazine under Hydrazine Derivatives Dimethyl Sulfide under Sulfides, Disulfides Dinitrotoluene under Simple Aromatic Nitro Compounds... 

Nitrobenzene under Simple Aromatic Nitro Compounds... 

Simple Aromatic Nitro Compounds Single-Ring Heterocyclic Sulfur Compounds Sodium Strontium... 

Vapor Phase Hydrogenations of Nitro Compounds. Catalytic hydrogenation of nitro compounds can be carried out in the vapor phase, provided the boiling point of the compound is low enough and the material is thermally stable. These two conditions effectively limit this process to aliphatic and relatively simple aromatic nitro compounds such as nitrobenzene or nitroxylene. Eady vapor-phase hydrogenation processes used fixed-bed catalysts. However, fluidized-bed catalytic vapor-phase hydrogenations, such as the one illustrated by the process for aniline, have become more common (see Amines, aromatic, aniline and derivatives). 

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

A variety of natural products and pharmaceutical agents contain a tetrahydroquinoline moiety [31]. Recently, a simple and general access to these heterocycles by a so-far unknown domino reaction of aromatic nitro compounds 7-65 and 2,3-dihydrofuran mediated by indium in water has been described by Li and coworkers (Scheme 7.19) [32]. It is assumed that the process is initiated by reduction of the nitro group in 7-65 to give the aniline 7-66 on treatment with indium in... 

Amination of aromatic nitro compounds is a very important process in both industry and laboratory. A simple synthesis of 4-aminodiphenyl amine (4-ADPA) has been achieved by utilizing a nucleophilic aromatic substitution. 4-ADPA is a key intermediate in the rubber chemical family of antioxidants. By means of a nucleophibc attack of the anilide anion on a nitrobenzene, a o-complex is formed first, which is then converted into 4-nitrosodiphenylamine and 4-nitrodiphenylamine by intra- and intermolecular oxidation. Catalytic hydrogenation finally affords 4-ADPA. Azobenzene, which is formed as a by-product, can be hydrogenated to aniline and thus recycled into the process. Switching this new atom-economy route allows for a dramatic reduction of chemical waste (Scheme 9.9).73 The United States Environmental Protection Agency gave the Green Chemistry Award for this process in 1998.74... 

Interestingly, aromatic nitro compounds, especially 4-alkylnitrobenzenes, are readily arylated at their side chains [67]. Simple substrates such as 4-nitro-toluene tend to undergo diarylation (Eq. 34). In contrast, only monoarylated products are obtained when a neighboring substituent exists in either the halides or the nitro compounds (Eqs. 35 and 36), probably due to steric reasons. 

I In electrophilic and nucleophilic substitution of aromatic nitro compounds different directing effects are dictated by electron distribution. The simple case of nitrobenzene rr-electron distribution is given in diagram Fig. 14a [2],and the Ifree valence of aromatic cations of nitrobenzene C KsNOi is given in Fig. I4h... 

Varma and his coworkers have described a simple and eflRcient procedure wherein aromatic nitro compounds are readily reduced to the corresponding amino compounds in good yields with hydrazine hydrate supported on alumina in the presence of iron(III) chloride (FeCls 6H2O), Fe(III) hydroxide, or Fe(III) oxides (Scheme 8.60) [159]. 

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