Meisenheimer complexes oxidation

Benzo[6]thiophene, methoxynitro-Meisenheimer complexes, 4, 816 Benzo[6]thiophene, 2-methyl-cycloaddition reactions, 4, 793 protonation, 4, 47 sulfonation, 4, 764 synthesis, 4, 879, 915 Benzo[6]thiophene, 3-methyl-cycloaddition reactions, 4, 793 1-oxide... 

McLafferty rearrangement 133, 163 Meisenheimer complexes 699, 702 Metal-chelated intermediates 838 Metal-halogen exchange 781, 784 Methionine, oxidation of 852-855 Methionine sulphone 853 Methionine sulphoxide 851-869 reduction of 1063 residues of... 

The complex formed between 4,6-dinitrobenzofurazan 3-oxide and potassium hydroxide has been evaluated as an explosive [1]. The structure is now7 believed to be that of a Meisenheimer complex [2], The analogous sodium, silver and barium salts are also explosive, the latter being less sensitive to initiation [3],... 

That the formation of molecular complexes (especially EDA complexes) can catalyse the decomposition of the cr-adduct has been discussed in Section n.E. Another possibility is that the substrate and catalyst (nucleophile or added base) form a complex which is then attacked by a new molecule of the nucleophile in this context catalysis need no longer be associated with proton removal. Thus, Ryzhakov and collaborators183 have recently shown that the N-oxides of 4-chloropyridine and 4-chloroquinoline act as jt-donors toward tetracyanoethylene and that the reactions of these substrates with pyridine and quinoline are strongly catalysed by the jr-acceptor. Similarly, the formation of a Meisenheimer complex between 1,3,5-trinitrobenzene and l,8-diazabicyclo[5,4,0]undec-7-ene in toluene has been assumed to take place via an association complex to explain the observed second-order in tertiary amine184. 

The formation of the C-X bond in hetero-cross coupling reactions is thought to proceed via a migration of the hetero atom to the aryl group, which develops a negative charge, which is Jt-stabilised by mesomeric interaction with acceptor substituents. Both for this reductive elimination and its reverse (oxidative addition) resonance-stabilised Meisenheimer complexes have been proposed [42,49,50,51], This stabilised structure is depicted in Figure 12.18. 

Thiophene, 2-hydroxy-5-methyl-synthesis, 4, 926 Thiophene, iodo-Grignard reagents, 4, 79, 831 photolysis, 4, 832 reactions, 4, 932 with phenyllithium, 4, 831 synthesis, 4, 835, 934 Ullmann coupling reactions, 4, 837 Thiophene, 2-isopropyl-3-methyl-synthesis, 4, 901 Thiophene, mercapto-reactions, 4, 78 stability, 4, 825 synthesis, 4, 80, 835, 930-931 tautomerism, 4, 38, 727 Thiophene, 2-mercapto-5-methylthio-synthesis, 4, 872 Thiophene, 2-methoxy-chloromethylation, 4, 759 Thiophene, 3-methoxy-chloromethylation, 4, 759 Thiophene, 5-methoxy-2,4-dinitro-Meisenheimer complexes, 4, 815 Thiophene, 2-methoxy-5-methyl-Vilsmeier formylation, 4, 759-760 Thiophene, 2-methoxy-3-nitro-reactions, 4, 827 Thiophene, 2-methyl-bromination, 4, 799-800 conformation, 4, 32 HNMR, 4, 730 metallation, 4, 773 synthesis, 4, 885, 887 trifluoroacetylation, 4, 751 Thiophene, 3-methyl-bromination, 4, 799-800 conformation, 4, 32 H NMR, 4, 730 metallation, 4, 60 oxidation, 4, 800... 

A wide variety of reactions other than substitutions and hydrolyses have been performed in microemulsions. Examples include alkylations [29], Knoevenagel condensations [13], oxidations [30,31], reductions [32], formation and decomposition of Meisenheimer complexes [33], aromatic substitution reactions such as nitration and bromination [34-36], nitrosation [37] and lactone formation, i.e. esterification [38-40]. Microemulsions have also been used for photochemical and electrochemical reactions [41-45]. 

Nucleophilic aromatic substitution for heteroatom nucleophiles through electrochemical oxidation of intermediate a-complexes (Meisenheimer complexes) in simple nitroaromatic compounds has been reported, see Gallardo, 1. Guirado, G. Marquet, J. J. Org. Chem. 2002, 67, 2548. 

Jackson-Meisenheimer complexes can serve in obtaining nitro derivatives of diphenyl. An original approach to this type of reaction was given by Wenner-ttrom [52]. He reacted a derivative of phenylsUver with 1,3,5-trinitrobenzene in the presence of pyridine. The oxidation of the o-complex yielded compound VI. 

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