Aromatic nitrations. silver nitrate

Since aliphatic hydrocarbons (unlike aromatic hydrocarbons, p. 155) can be directly nitrated only under very special conditions, indirect methods are usually employed for the preparation of compounds such as nitroethane, CjHsNO. When ethyl iodide is heated with silver nitrite, two isomeric compounds are formed, and can be easily separated by fractional distillation. The first is the true ester, ethyl nitrite, C,HiONO, of b.p. 17° its identity is shown by the action of hot sodium hydroxide solution, which hydrolyses it, giving ethanol and... 

Aliphatic mono-halides, and aromatic hydrocarbons with halogen in side-chain, precipitate silver hdide on treatment with cold aqueous silver nitrate solution. 

Aromatic aldehydes react with the dimedone reagent (Section 111,70,2). All aromatic aldehydes (i) reduce ammoniacal silver nitrate solution and (ii) restore the colour of SchifiF s reagent many react with sodium bisulphite solution. They do not, in general, reduce Fehling s solution or Benedict s solution. Unlike aliphatic aldehydes, they usually undergo the Cannizzaro reaction (see Section IV,123) under the influence of sodium hydroxide solution. For full experimental details of the above tests, see under Ali-phalic Aldehydes, Section 111,70. They are easily oxidised by dilute alkaline permanganate solution at the ordinary temperature after removal of the manganese dioxide by sulphur dioxide or by sodium bisulphite, the acid can be obtained by acidification of the solution. 

Nitro compounds and their reduction products. Tertiary nitro compounds (these are generally aromatic) are reduced by zinc and ammonium chloride solution to the corresponding hydroxylamines, which may be detected by their reducing action upon an ammoniacal solution of silver nitrate or Tollen s reagent ... 

Silver fluorocomplexes are also used ia the separation of olefin—paraffin mixtures (33), nitration (qv) of aromatic compounds (34), ia the synthesis of (9-bridged bicycHcs (35), pyrroles (36), cyclo-addition of vinylbromides to olefins (37), and ia the generation of thioben2oyl cations (38). 

Under the chosen conditions aromatic compounds are nitrated to nitroaromatics [1]. The detection of rotenone [1] (see below) depends on the reduction of silver ions, incorporated into the layer, to metallic silver in the presence of ammonia [4]. The mechanism of the reaction of many substances leading to fluorescent derivatives has not yet been elucidated [2],... 

A novel type of ligands are tertiary stibines containing heterocyclic aromatic groups (Y-2-C4H3)3Sb (Y = S, O, or NMe) which with silver nitrate form polymeric 2 1 complexes, [ (Y-2-C4H3)3Sb 2AgN03]x.56... 

From the solubilities of aromatic hydrocarbons in aqueous silver nitrate it is clear that there, is an interaction with the silver ion to give monoargentated and, to a lesser extent, diargentated hydrocarbons. The bond to silver ion is probably of the rc-type, since the differences in the association constants for the complex with the three isomeric xylenes are small and since a single methyl group stabilizes the complex almost as much as two.279... 

Analogous results were obtained from investigations as to the solubility of aromatic hydrocarbons in aqueous silver nitrate solution... 

Aromatic cation-radicals can also react with NOj", giving nitro compounds. Such reactions proceed either with a preliminary prepared cation-radical or starting from nncharged componnd if iodine and silver nitrite are added. As for mechanisms, two of them seem feasible—first, single electron transfer from the nitrite ion to a cation-radical and second, nitration of ArH with the NOj radical. This radical is quantitatively formed when iodine oxidizes silver nitrite in carbon tetrachloride (Neelmeyer 1904). 

Methyla-arylacetates. These esters have been obtained by oxidative rearrangement of alkyl aryl ketones with thallium(III) nitrate in acidic methanol or trimethyl orthoformate (4,496 5, 656 7, 362). A new method, which avoids the toxic TTN, is based on the Woodward version of the Prevost reaction. Thus, treatment of the ketone with iodine (or bromine) and silver nitrate (2 equiv.) in refluxing methanol containing trimethyl orthoformate results in methyl a-arylacetates in 90% yield from simple substrates. Yields are lowered by electron-withdrawing substituents on the aromatic group and by a-branching in the alkyl group.2... 

During their work on the arylation of aromatic compounds by substitution, Fujiwara, et al. observed biaryl formation when aromatic compounds were placed in the presence of olefin-palladium complexes and silver nitrate.80 Developing this reaction as a method for biphenyl synthesis, these authors showed that the more stable the olefin-palladium complex was, the lower the yield. Ethylene dichloropalladium proved to be the best choice, when used with silver nitrate. However, the reaction required stoichiometric amounts of both catalysts (Scheme 10.47). Benzene derivatives substituted by electron-donating or -withdrawing groups reacted as well, but a mixture of regioisomers was produced, except for nitrobenzene, which only gave m,m -dinitrobiphenyl. 

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