Sulfide aromatic nitro compounds

Zinin Reduction. The method of reducing aromatic nitro compounds with divalent sulfur is known as the Zinin reduction (57). This reaction can be carried out in a basic media using sulfides, polysulfides, or hydrosulfides as the reducing agent. These reactions can be represented as follows when the counter ion is sodium ... 

The Zinin reduction is also usehil for the reduction of aromatic nitro compounds to amines in the laboratory. It requires no special equipment, as is the case with catalytic hydrogenations, and is milder than reductions with iron and acid. Usually ammonium or alkah sulfides, hydrosulftdes or polysulftdes are used as the reactant with methanol or ethanol as the solvent. 

Reduction of aromatic nitro compounds by sulfide catalyzed by extracellular compounds excreted into the medium during growth of Streptomyces griseoflavus (Glaus et al. 1992). 

Electrochemically generated nickel is very selective for the reduction of aromatic nitro compounds into anilines, in which alkenyl, alkynyl, halo, cyano, formyl, and benzyloxy groups are not affected.84 Sodium sulfide has been used for the selective reduction of aromatic nitro group in the presence of aliphatic nitro groups (Eq. 6.44).85... 

Furthermore, aromatic nitro compounds may be reduced to hydroxylamines by tita-nium(in) chloride or ammonium sulfide ", as well as by electrochemical reduction . 

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

Saturated hydrocarbons < olefins < aromatic hydrocarbons = organic halides < sulfides < ethers < nitro compounds < esters = aldehydes = ketones < alcohols = amines < sulfones < amides < carboxylic acids... 

The iron sulfide complex (10) resembles the active sites of oxidized rubredoxins nonheme iron-sulfur proteins. The complex catalyzes the reductions of aromatic nitro compounds to A -arylhydroxylamines by thiol (equation 11 ). The method offers a facile, high yield approach to N-arylhydroxylamines. For example, p-dinitrobenzene was reduced to p-nitrophenylhydroxylamine in 92% yield. 

Interest in an old reducing agent, sodium sulfide, was renewed when it was discovered that its reactivity toward nitro groups was sensitive to water. In the absence of water, the aromatic nitro group in (28) can be reduced selectively to (29), without reduction of the aliphatic nitro group, but compounds such as (30), which contain a tertiary aliphatic nitro group eliminate the nitro moiety to yield styrene derivatives (31 Scheme 5). A unique application of the sulfide reduction involves the preparation of isomerically pure substituted aromatic nitro compounds and anilines. ... 

Successful partition chromatography requires a proper balance of intermolecular forces among the three participants in the separation process—the analyte, the mobile phase, and the stationary phase. These intermoleculai forces are described qualitatively in terms of the relative polarity possessed by each of the three components. In general, the polai ities of common organic functional groups in increasing order are aliphatic hydrocarbons < olefins < aromatic hydrocarbons < halides < sulfides < ethers < nitro compounds < esters = aldehydes = ketones < alcohols = amines < sulfones < sulfoxides < amides < carboxylic acids < water. 

Under suitable conditions it is possible to isolate the A-substituted hydroxylamines that are formed as intermediates in the reduction of nitro compounds. For this purpose it is essential in the reduction of aromatic nitro compounds to work with neutral or nearly neutral solutions suitable reducing agents are hydrogen and platinum oxide catalysts in glacial acetic acid,82,83 zinc dust in ammonium chloride solution,84 aluminum amalgam,85 and ammonium sulfide.86 Aliphatic nitro compounds may be reduced as their alkali salts (nitronates) by diborane in tetrahydrofuran, then giving A-alkylhydroxyl-amines 87 for instance, A-cyclohexylhydroxylamine is thus obtained from nitrocyclohexane in 53% yield. However, aliphatic nitro compounds are converted into A-alkylhydroxylamines more simply by catalytic hydrogenation in the presence of palladium-barium sulfate unlike aromatic nitro compounds, aliphatic nitro compounds require an acid medium for reduction to hydroxylamines an oxalic acid medium has proved the most suitable. 

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

Sulfur Dyes. These dyes are synthesized by heating aromatic amines, phenols, or nitro compounds with sulfur or, more usually, alkah polysulfides. Unlike most other dye types, it is not easy to define a chromogen for the sulfur dyes (qv). It is likely that they consist of macromolecular stmctures of the phenothiazone-thianthrone type (72), in which the sulfur is present as (sulfide) bridging links and thiazine groups (1). 

The routes give, using well-known condensation and radical reactions, bakelites (I), polyazophenylenes (II), polyimides (III), polyurethanes (IV), nitro compounds and polyamides (V), aromatic polyethers and polyesters (VI), polychalcones (VII), polyphenylene sulfides (IX), ammonia lignin (X), carbon fibers (XI), silicones (XII), and phosphorus esters (XIII). In addition, radiation and chemical grafting can be used to obtain polymers of theoretical interest and practical use. Although the literature on the above subject is very large, there are comprehensive summaries available (1,28,69). 

Saturated hydrocarbons Olefinic hydrocarbons Aromatic hydrocarbons Halocarbons Mercaptans Sulfides CS2 Ethers Ketones Aldehydes Esters Tertiary amines Nitro compounds (without a-H atoms) Nitriles (without a-atoms)... 

---