Reduction partial-dinitro compounds

Sulfide reduction employs sodium sulfide, sodium polysulfide, or sodium hydrosulfide. An important feature of this type of reducing system is its adaptability to bring about stepwise reduction of dinitro compounds. Partial reduction is illustrated with m-dinitro-benzene, which can be reduced to m-nitro-aniline with sodium sulfide under controlled conditions ... 

Aminobenzo[6]thiophene is prepared from 7-hydroxybenzo[6]-thiophene by means of the Bucherer reaction it may be converted into 7-nitrobenzo[6]thiophene via the diazonium salt.84 5,7-Diamino-3-phenylbenzo[6]thiophene and its 2-carboxylic acid are prepared by reduction of the corresponding dinitro compound.334 Partial reduction of o,7-dinitro-3-phenylbenzo[6]thiophene-2-carboxylic acid with ethanolic ammonium sulfide affords 7-amino-5-nitro-3-phenylbenzo-[6]thiophene-2-carboxylic acid, the amino group of which may be replaced by hydrogen or iodine via the diazonium salt.334 7-Amino-4-methoxybenzo[6]thiophene is mentioned in the patent literature.560... 

Some aromatic dinitro compounds, e.g. w-dinitrobenzene, may be characterised by partial reduction to the nitroamine. Experimental details using sodium polysulphide as the reducing agent are to be found in Expt 6.51. 

With dinitro compounds in which the nitro groups are in the 2 and 4 positions relative to an alkyl, hydroiqrl, alkoxy, or amino group, partial reduction usually leads to reduction of the 2-nitro group. 

Another promising reaction is the partial reduction of the dinitro compounds followed by hydrolysis of the sulphonic group [98] (14) ... 

Selective hydrogenation of one or two nitro groups in an aromatic dinitro compound is the basis for the synthesis of otherwise unattainable molecules. Carefully chosen catalysts, under totally different reaction conditions, have been met with success. Partial reduction of 2,6-dinitroanilines to nitrophenylenediamines occurs in 60-90% yield over 10% palladium-on-carbon at RT [equation (a)], although most heterogeneous catalysts do not afford such selectivity. 

Some aromatic dinitro-compounds may be characterized by partial reduction to the corresponding nitro-amines. 

Complete reduction of TNT and its partially reduced derivatives can also be accomplished when these compounds are present in soil under strict anaerobic conditions (Fig. 14). Notably, after 4 days TNT and partially reduced nitrotoluenes have completely disappeared from the aqueous phase, whereas considerable amounts of these contaminants (approx. 180 mg TNT and 40 mg ADNT per kg ) are still present in soil. Obviously, at these lower levels of contamination the process of desorption becomes slower than the reduction reaction. The reduction of these compounds in heaps or compost piles, where aerobic or semiaerobic conditions prevail, remains incomplete. Products of partial reduction such as mononitro-diamino- and dinitro-monoamino-toluenes and azoxy compounds are extractable from soil. In contrast to the observations made in the absence of soil (Fig. 13), TAT as a product of complete reduction of TNT is irreversibly bound to the soil matrix and thus remains undetectable in the aqueous phase (23). Interestingly, this irreversible binding does not require the participation of O2. Therefore, primary adsorption of TAT corresponds to the well-known mechanism of intercalation of diamines into clay minerals such as montmorillonite (18,48). 

Reduction of tetrazolo[l,5-ft][l,2,4]triazine derivatives (16) was also studied <76JOC4l>. Catalytic hydrogenation resulted in partial reduction at the C(7)—N(8) bond to give (17). Sodium borohy-dride, in contrast, led to the formation of a tetrahydro derivative (19). Behavior of both reduction products (17) and (19) towards nitration reagent was also studied, and nitrations of the NH groups have been detected (i.e., (17) gave the mononitro compound (18), whereas (19) afforded the dinitro derivative (20)). 

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