Nitrobenzene, substitution

Enhanced binding of sodium ions by electrochemically reduced nitrobenzene substituted lariat ethers (e.g. 33) has been observed.89 This is attributed to interaction between ring bound Na+ and the reduced side chain. Log Ks (33-Na) has been estimated to be 6.33, where Ks is the binding constant for Na+ and the anion of (33). 

Halogen substituents are ortho, para-directing, and the disposition in m-dichlorobenzene is such that their effects reinforce each other. The major product is 2,4-dichloro-l-nitrobenzene. Substitution at the position between the two chlorines is slow because it is a sterically hindered position. 

A great deal of information is also available on the reduction of nitrobenzene, substituted nitrobenzenes, and di- and tri-nitrobenzenes, due to their convenience as model compounds and importance as munitions (e.g., 34-40). 

Among more recent investigations the experiments of Hammond, Medic and Hedges [69] deserve special attention. They explain the influence of the medium on orientation when nitrating 2,5-dichloro- and 2,5-dibromo-nitrobenzene. Substitution into all three free positions takes place and derivatives ortho-, meta- and... 

Irenes. Nitrobenzenes substituted with chloro, methyl, or meth-laced to the corresponding anilines by formic acid and this ruth-yields generally greater than 90%. Alcoholic solvents increa.se the... 

Nucleophilic displacement of the nitro group of nitrobenzenes substituted with a variety of electron-withdrawing groups is readily possible at 25°C with HMPA as solvent.1 8 Carbon, oxygen, and sulfur nucleophiles have been used with excellent yields reported. 

Bromopyrimidine is formed in 71-88% yield using bromine in solvents like benzene or nitrobenzene. Substitution on carbon is preceded by a vigorous reaction at lower temperatures involving A-bromination and perbromide formation <90AHC(47)325>. Bromination in the vapor phase at 230°C gives the 5-bromopyrimidine in 62% yield <73JHC153>. 

Gustowski. D.A. Echegoyen, L. Goli. D.M. Kaifer. A. Schultz, R.A. Gokel. G.W. Electrochemically switched cation binding in nitrobenzene-substituted, nitrogen-pivot lariat ethers. J. Am. Chem. Soc. 1984,106. 1633-1635. 

Good yields of azobenzenes were also obtained for several nitrobenzenes substituted with meta or para electron-releasing substituents. On the other hand, ortho substituents favoured the formation of anilines, perhaps because of their steric effect in retarding the competing reaction leading to azo compounds. 

Tg measurements have been performed on many other polymers and copolymers including phenol bark resins [71], PS [72-74], p-nitrobenzene substituted polymethacrylates [75], PC [76], polyimines [77], polyurethanes (PU) [78], Novolac resins [71], polyisoprene, polybutadiene, polychloroprene, nitrile rubber, ethylene-propylene-diene terpolymer and butyl rubber [79], bisphenol-A epoxy diacrylate-trimethylolpropane triacrylate [80], mono and dipolyphosphazenes [81], polyethylene glycol-polylactic acid entrapment polymers [82], polyether nitrile copolymers [83], polyacrylate-polyoxyethylene grafts [84], Novolak type thermosets [71], polyester carbonates [85], polyethylene naphthalene, 2,6, dicarboxylate [86], PET-polyethylene 2,6-naphthalone carboxylate blends [87], a-phenyl substituted aromatic-aliphatic polyamides [88], sodium acrylate-methyl methacrylate multiblock copolymers [89], telechelic sulfonate polyester ionomers [90], aromatic polyamides [91], polyimides [91], 4,4"-bis(4-oxyphenoxy)benzophenone diglycidyl ether - 3,4 epoxycyclohexyl methyl 3,4 epoxy cyclohexane carboxylate blends [92], PET [93], polyhydroxybutyrate [94], polyetherimides [95], macrocyclic aromatic disulfide oligomers [96], acrylics [97], PU urea elastomers [97], glass reinforced epoxy resin composites [98], PVOH [99], polymethyl methacrylate-N-phenyl maleimide, styrene copolymers [100], chiral... 

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