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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. [2]
2,4,6-Tribromoaniline is a brominated derivative of aniline with the formula C 6 H 4 Br 3 N. It is used in organic synthesis of pharmaceuticals, agrochemicals and fire-extinguishing agents. It is used in organic synthesis of pharmaceuticals, agrochemicals and fire-extinguishing agents.
For example, reaction of aniline with sulfuric acid at 180 °C produces sulfanilic acid, H 2 NC 6 H 4 SO 3 H. If bromine water is added to aniline, the bromine water is decolourised and a white precipitate of 2,4,6-tribromoaniline is formed. To generate the mono-substituted product, a protection with acetyl chloride is required:
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
The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation. The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer , when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I ...
The overall reaction mechanism, denoted by the Hughes–Ingold mechanistic symbol S E Ar, [3] begins with the aromatic ring attacking the electrophile E + (2a). This step leads to the formation of a positively charged and delocalized cyclohexadienyl cation, also known as an arenium ion, Wheland intermediate, or arene σ-complex (2b).
The anion reacts with bromine in an α-substitution reaction to give an N-bromoamide. Base abstraction of the remaining amide proton gives a bromoamide anion. The bromoamide anion rearranges as the R group attached to the carbonyl carbon migrates to nitrogen at the same time the bromide ion leaves, giving an isocyanate.
The reaction proceeds through generation of an acylium center. The reaction is completed by deprotonation of the arenium ion by AlCl 4 −, regenerating the AlCl 3 catalyst. However, in contrast to the truly catalytic alkylation reaction, the formed ketone is a moderate Lewis base, which forms a complex with the strong Lewis acid aluminum ...