From nitro compounds

Augustine, Catalytic Hydrogenation, Maicel Dekker, New York (1965), Chpt 5 M. Freifelder, Practical Catalytic Hydrogenation, Wiley Interscience, New York (1971), Chpt 10 M. Freifelder, Catalytic Hydrogenation in Organic Synthesis Procedures and Commentary,  

Rylander, Hydrogenation Methods, Academic Press, New Yoik (1983), Chpt 8 Comprehensive Organic Synthesis, Eds. B. M. Trost and I. Fleming, Pergamon, Oxford (1991), 

FeS04-7H20, NiSO 6H20, KHC03/NaBH4/ C02, H20 

cal KBH4-NiCl2-6H20-C H2 cal NaB ( -exchange resin-PdCl2 H2, cat Pd-C 

cat Pd(hfacac)2-Me3Si(OSiHMe) OSiMe3 H2, cat montmorillomte-Pd H2, cat PtOj 

FeS04 7H20, NiS04-6H20, KHCOj/NaBttj/ 

cat Pt02, K2C03) CH3OH H2, cat Pt salt-NaBH4 cat Pd, cyclohexene cat Pd-C, cyclohexene 

NaBH SnCl2-2H20, EtOH Chem Phann Bull 29 1443 (1981) JACS 114 980 (1992) 

HFe(C0)4, CF3C02H LiBR, MeOH, diglyme NaBH2S3 NaBR, cat Pd-C NaBR, cat Pd-C, H20 NaBRt, SnCl2 2H2Ot EtOH 

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As discussed in Chapter 6, nitro compounds are converted into amines, oximes, or carbonyl compounds. They serve as usefid starting materials for the preparation of various heterocyclic compounds. Especially, five-membered nitrogen heterocycles, such as pyrroles, indoles, ind pyrrolidines, are frequently prepared from nitro compounds. Syntheses of heterocyclic compounds using nitro compounds are described partially in Chapters 4, 6 and 9. This chapter focuses on synthesis of hetero-aromadcs fmainly pyrroles ind indolesi ind saturated nitrogen heterocycles such as pyrrolidines ind their derivadves. 

Azoxy compounds can be obtained from nitro compounds with certain reducing agents, notably sodium arsenite, sodium ethoxide, NaTeH, NaBH4—PhTeTePh, and glucose. The most probable mechanism with most reagents is that one molecule of nitro compound is reduced to a nitroso compound and another to a hydroxylamine 119-42), and these combine (12-51). The combination step is rapid compared to the reduction process. Nitroso compounds can be reduced to azoxy compounds with triethyl phosphite or triphenylphosphine or with an alkaline aqueous solution of an alcohol. ... 

In 1988, Ono and Maruyama reported a very simple synthesis of octaethylporphyrin (OEP) from 3,4-diethylpyrrole-2-carboxylate, as shown in Eq. 10.44 49 Reduction of this pyrrole with LiAlH4 gives 2-hydroxyethylpyrrole, which is converted into OEP on treatment with acid and an oxidizing agent. This route is very convenient for synthesis of porphyrins. This method is now used extensively for synthesis of P-substituted porphyrins.50 For example, a highly conjugated porphyrin, shown in Eq. 10.45, has been prepared by this route.51 The requisite pyrroles are prepared from nitro compounds or sulfones thus, various substituents are readily introduced into porphyrins. 

Reductive carbonylation of nitro compounds (in particular aromatic dinitro compounds) is an important target in industry for making diisocyanates, one of the starting materials for polycarbamates. At present diisocyanates are made from diamines and phosgene. Direct synthesis of isocyanates from nitro compounds would avoid the reduction of nitro compounds to anilines, the... 

The molecular ion peak (odd number) of aliphatic nitrites (one N present) is weak or absent. The peak at m/z 30 (NO+) is always large and is often the base peak. There is a large peak at m/z 60 (CH2=ONO) in all nitrites unbranched at the a carbon this represents cleavage of the C—C bond next to the ONO group. An a branch can be identified by a peak at m/z 74, 88, or 102,. Absence of a large peak at m/z 46 permits differentiation from nitro compounds. Hydrocarbon peaks are prominent, and their distribution and intensities describe the arrangement of the carbon chain. 

Nitramines differ from nitro compounds in possessing a somewhat better oxygen balance, due to the fact that the group N—N02 gives twice the volume of nitrogen as the group C—N02. On the other hand nitramines have a worse oxygen balance than nitric esters. 

Arylhydroxy la mines, whether derived from nitro compounds by reduction or amines by N-hydroxylation, have been shown to be involved in the toxicity of a number of compounds. The possibility of reduction followed by oxidation in a cyclical fashion with the continual production of toxic metabolites has important toxicological implications. 

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