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Brominating aniline with elemental bromine gives 2,4,6-tribromoaniline. This is then diazotized, then reacted with ethanol to replace the diazonium group with hydrogen, forming 1,3,5-tribromobenzene. [3] It has also been prepared by these methods: [3] replacement of the amino group of 3,5-dibromoaniline with bromine
One classic reaction is the Chichibabin reaction (Aleksei Chichibabin, 1914) in which pyridine is reacted with an alkali-metal amide such as sodium amide to form 2-aminopyridine. [ 6 ] In the compound methyl 3-nitropyridine-4-carboxylate, the meta nitro group is actually displaced by fluorine with cesium fluoride in DMSO at 120 °C.
Bromobenzene is an aryl bromide and the simplest of the bromobenzenes, consisting of a benzene ring substituted with one bromine atom. Its chemical formula is C 6 H 5 Br . It is a colourless liquid although older samples can appear yellow.
4-Bromoaniline is a compound where an aniline molecule is substituted with a bromine atom on the para position. Commercially available, this compound may be used as a building block, e.g. in the preparation of monobrominated biphenyl via the Gomberg-Bachmann reaction .
Nickel-catalyzed cyanations avoid the use of precious metals, and can take advantage of benzyl cyanide or acetonitrile as a cyanide source, via reductive C-C bond cleavage: [9] Sandmeyer cyanation is a means of converting aniline derivatives to benzonitriles. [10]
In numerous variants that have been developed, other transition metal salts, including copper(II), iron(III) and cobalt(III) have also been employed. [7] Due to its wide synthetic applicability, the Sandmeyer reaction, along with other transformations of diazonium compounds, is complementary to electrophilic aromatic substitution .
For example, aniline has resonance structures with negative charges around the ring system: The amino group can donate electron density through resonance. Attack occurs at ortho and para positions, because the (partial) formal negative charges at these positions indicate a local electron excess.
This is especially so in transition metal chemistry, where numerous experiments have been done to determine the relative ordering of ligands and transition metal ions in terms of their hardness and softness. HSAB theory is also useful in predicting the products of metathesis reactions. In 2005 it was shown that even the sensitivity and ...