Benzenamine, 2- - Aniline

EXAMPLES methanamine (methylamine) Al, Al-dipropyl-l-propanaimne (tnpropylaumie) benzenamine (aniline)... 

Explain why the bromination of benzenamine (aniline) gives 2,4,6-tribromo-benzenamine (2,4,6-tribromoaniline), whereas the nitration with mixed acids gives 3-nitrobenzenamine (mefa-nitroaniline),... 

Alkenamines, or enamines, R—CH=CHNH2, usually are not stable and rearrange readily to imines (Section 16-4C). An important exception is benzenamine (aniline), C6H5NH2, which has an amino group attached to a benzene ring. The imine structure is less favorable by virtue of the considerable stabilization energy of the aromatic ring ... 

P.14) (P.14) Benzenamine, aniline, phenylamine, benzenamine, phenylazane, aminobenzene 62-53-3 ... 

Both inductive and resonance effects are involved. The favored reaction proceeds through the most stabilized (or least destabilized) intermediate carbocation. Study carefully the re.sonance forms pictured for the possible cations derived from electrophilic attack on meihylbenzene and (trilluoromethyl)benzene (Section I6-I), and on benzenamine (aniline), benzoic acid, and a haiobenzene (Section 16-2). Notice the types of groups that fall into the different categories in Table 16-1. In particular, notice the following two general trends ... 

Diazotization Synthesis of arenediazonium salts from benzenamines (anilines) using cold nitrous acid. t-Dicarbonyl compound A useful intermediate bearing two carbonyl groups adjacent to the same... 

Synonyms 2-((4-Aminophenyl) methyl) benzenamine Aniline, 2,4 -methylenedi- 2, 4-Bis (aminophenyl) methane 2,4 -Diaminodiphenylmethane o,p -Diaminodiphenylmethane 2,4 -Diphenylemthanediamine 2,4 -Methylenebis (aniline)... 

Aromatic amines are nsed mainly in the manufacture of dyes. Benzenamine (aniline), the simplest aromatic amine, is a toxic compound a number of other aromatic amines such as 2-naphthylamine and benzidine are potent carcinogens ... 

Aromatic nitration is the best way to introduce nitrogen-containing substituents into the benzene ring. The nitro group functions as a directing group in further substitutions (Chapter 16) and as a masked amino function (Section 16-5), as unraveled in benzenamines (anilines Section 22-10). 

Benzene rings bearing the groups -NH2 and -OH are strongly activated. For example, halogenations of benzenamine (aniline) and phenol not only take place in the absence of catalysts but also are difficult to stop at single substitution. The reactions proceed very rapidly and, as in activation by alkyl groups (Section 16-2), furnish exclusively ortho- and para-... 

Electrophilic Brominations of Benzenamine (Aniline) and Phenol Give Ortho and Para Substitution... 

Benzenamine (Aniline) 2,4,6-Tribromobenzenamiiie (2,4,6-Tribromoaniline) Phenol 2,4,6-Tribromophenol... 

Ortho, Meta, and Para Attack on Benzenamine (Aniline)... 

For an example of applying this capability in synthetic strategy, consider the preparation of 3-bromobenzenamine. Direct bromination of benzenamine (aniline) leads to complete ortho and para substitution (Section 16-3) and is therefore useless. However, bromination of nitrobenzene allows preparation of 3-bromonitrobenzene, which can be converted into the required target molecule by reduction. The outcome is a benzene derivative in which two ortho, para directors emerge positioned meta to each other. 

We noted in Section 16-3 that electrophilic attack on benzenamine (aniline) and phenol are difficult to stop at the stage of monosubstitution because of the highly activating nature of the NH2 and OH groups. In addition, with these Lewis basic functions, complications can... 

Benzenamine (Aniline) A-Phenylacetamide (Acetanilide) SO3H SO3H... 

Like other amines, benzenamine (aniline) can be benzylated with chloromethylbenzene (benzyl chloride), C6H5CH2CI. In contrast to the reaction with alkanamines, which proceeds at room temperature, this transformation requires heating to between 90 and 95 C. Explain. (Hint See Section 21-4.)... 

Amines react with nitrous acid, through nucleophilic attack on the nitrosyl cation, NO. The product depends very much on whether the reactant is an alkanamine or a benzenamine (aniline) and on whether it is primary, secondary, or tertiary. This section deals with alkanamines aromatic amines will be considered in the next chapter. 

How does the benzene ring modify the behavior of neighboring reactive centers This chapter takes a closer look at the effects exerted by the ring on the reactivity of alkyl substituents, as well as of attached hydroxy and amino functions. We shall see that the behavior of these groups (introduced in Chapters 3, 8, and 21) is altered by the occurrence of resonance. After considering the special reactivity of aryl-substituted (benzylic) carbon atoms, we turn our attention to the preparation and reactions of phenols and benzenamines (anilines). These compounds are found widely in nature and are used in synthetic procedures as precursors to substances such as aspirin, dyes, and vitamins. 

Treatment with potassium amide results in benzenamine (aniline). 

Why is benzyne so strained Recall that alkynes normally adopt a linear structure, a consequence of the sp hybridization of the carbons making up the triple bond (Section 13-2). Becanse of benzyne s cyclic strnctnre, its triple bond is forced to be bent, rendering it nnnsnally reactive. Thns, benzyne exists only as a reactive intermediate under these conditions, being rapidly attacked by any nucleophile present. For example (step 2), amide ion or even ammonia solvent can add to furnish the product benzenamine (aniline). Becanse the two ends of the triple bond are equivalent, addition can take place at either carbon, explaining the label distribntion in the benzenamine obtained from " C-labeled chlorobenzene. 

As mentioned in Section 22-4, V-nitrosation of primary benzenamines (anilines) furnishes arenediazonium salts, which can be used in the synthesis of phenols. Arenediazonium salts are stabilized by resonance of the tt electrons in the diazo function with those of the aromatic ring. They are converted into haloarenes, arenecarbonitriles, and other aromatic derivatives through replacement of nitrogen by the appropriate nucleophile. 

What is the principal product after the slurry obtained on treating benzenamine (aniline) with potassium nitrite and HCl at 0°C has been added to 4-ethylphenol ... 

Starting with benzenamine (aniline) and pyridine, propose a synthesis of the antimicrobial sulfa drug sulfapyridine. 

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