Nitro-compounds, aromatic, reactions table

Primary, secondary and tertiary aliphatic amines are efficiently converted to nitro compounds in 80-90 % yield with dimethyldioxirane, a reagent prepared from the reaction of oxone (2KHSO5-KHSO4-K2SO4) with buffered acetone. Dimethyldioxirane (DMDO) has been used for the synthesis of 1,3,5,7-tetranitroadamantane (71) from the corresponding tetraamine as the tetrahydrochloride salt (70) and is an improvement over the initial synthesis using permanganate anion (Table 1.7). ° Oxone is able to directly convert some aromatic amines into nitro compounds. 

GSH may also be coupled to electrophilic reaction intermediates nonenzymatically or by GSH transferase (GST)-catalyzed reactions. Many different types of substrates will undergo GSH conjugation, including epoxides, halogenated compounds, aromatic nitro compounds, and many others. In these reactions, GSH can interact with an electrophilic carbon or heteroatom (O, N, and S) [35]. One such substrate is a reactive metabolite of acetaminophen (APAP), N-acetyl-p-benzoquinonimine (NAPQI), which will readily form a GSH conjugate (Scheme 3.2). Other examples of Phase II bioactivation reactions that lead to toxic endpoints are shown in Table 3.1. 

There have been numerous applications of controlled-potential coulometry to analysis. Many electrodeposition reactions that are the basis of electrogravimetric determinations can be employed in coulometry as well. However, some electrogravimetric determinations can be used when the electrode reactions occur with less than 100% current efficiency, for example, the plating of tin on a solid electrode. Coulometric determinations can, of course, also be based on electrode reactions in which soluble products or gases are formed (e.g., reduction of Fe(III) to Fe(II), oxidation of 1 to I2, oxidation of N2H4 to N2, reduction of aromatic nitro compounds). Many reviews concerned with controlled-potential coulometric analysis have appeared (1, 20-22) some typical applications are given in Table 11.3.2. 

Table 3 (No. 16) shows that ( )-p-nitro-cmnamate or derivatives can be reduced by enoate reductase, too. However, this reaction can be performed only with isolated enoate reductase using NADH as electron donor. Reduced methylviologen spontaneously reacts with nitro groups. Aliphatic as well as aromatic nitro compounds are also reduced by ferredoxins present in clostridia (26).

Attack other than on the amino group apparently does represent a competitive reaction course when the substituents on the aromatic ring are less electronegative than the nitro group. This is demonstrated by the strong coloration and tar formation observed when N,IV-dimethyl-aniline and p-chloro-N,A7-dimethylaniline are ozonized and by the fact that more ozone is consumed by these compounds than can be accounted for by side chain oxidation (Table III, Experiments 1 and 2). 

For less activated aromatic systems (those without a nitro substituent), the halogcn-ex-changc reaction has been investigated with potassium fluoride in a variety of polar aprotic solvents in the presence or absence of a catalyst (see Table 13). Many different types of catalysts have been investigated these include crown ethers, quaternary ammonium salts, 3,164 pjjos-phonium salts, aminophosphonium salts, compounds containing a phosphorus and an amino function, and inorganic fluorides of boron, aluminum, tin, phosphorus, titanium and zirconium. Different forms of potassium fluoride have been used these include spray-dried potassium fluoride, freeze-dried potassium fluoride, potassium fluoride recryslal-lized from methanol, and potassium fluoride dispersed on caleium fluoride. ... 

The o -complexes formed by the addition of CN to nitroarenes (mono-, di-, and tri-nitro derivatives) have been obtained in good yields (38 6%). The electrochemical oxidation of these o -complexes leads to re-aromatized compounds as a result of departure of two electrons and a proton, thus formally corresponding to the formal loss of H (Scheme 7, Table 3). The reaction is very clean, recovering only the starting material in addition to the reaction products. Yields are varied from 35 to 86% where a low yield of the Sn product is obtained (<15%), the Sn product is formed in approximately 30% yield. 

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