Benzenamine derivatives

This is one example of a group of formally related rearrangements in which a substituent, Y, attached to the nitrogen of a benzenamine derivative migrates... 

Other Names Aniline, 4,4 -(3H-2,l-benzoxathiol-3-ylidene)di-, S,S-dioxide Benzenamine, 4,4 -(3H-2,1 -benzoxathiol-3-ylidene) -, S,S-dioxide o-Toluenesulfonicacid, a,a- (p-aminophenyl) -a-hydroxy-, y-sultone 3H-2,l-Benzoxathiole, benzenamine deriv. Anihnesulfonephthalein CA Index Name Benzenamine, 4,4 -(l,l-dioxido-3H-2,l-benzoxathiol-3-ylidene)fci5 -CAS Registry Number 4538-11-8 Merck Index Number Not listed Chemical Structure... 

Other cyclohexyl compounds are obtained by catalytic hydrogenation of the corresponding benzene derivatives. Thus cyclohexanol is obtained from benzenol, and cyclohexanamine is obtained from benzenamine (aniline) ... 

The utility of all these transformations may become clearer if you work Exercise 23-34. It will give you practice in seeing how various benzene derivatives can be prepared from primary benzenamines. Later in the chapter we shall see that amines can be prepared by the reduction of nitro compounds, which permits the following sequence of reactions ... 

Claisen-Schmidt condensation, 720, 728 with methylamine, 673, 873 nitration, 467, 873 reductive amination, 881 with vinyllithium, 556 Benzenamine, 859. See also Aniline Benzene, 54, 399-406, 433 34 acidity of, 552, 577 Birch reduction of, 413-414 derivatives, nomenclature of, 406-408 electrophilic aromatic substitution in,... 

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 ... 

Tylenol, on the other band, is an amide and much more resistant to nucleopbilic attack. Hydrolysis would require extended heating, and strung acid or biise is required. Indeed, amides derived from benzenamine, such as A -acctylbenzen imine (ucettmilide), are commonly purified by recrystallization from neutral boiling water, further illustrating their stability.]... 

Aromatic amines are named as derivatives of aniline. In the CA system, aniline is called benzenamine these CA names are shown in parentheses. 

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. 

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. 

A series of new 5,6-dihydro-indolo[l,2-a]quinoxaline derivatives 533 has been prepared in moderate to excellent yields from 2-(indol-l-yl)benzenamines 532 with aromatic aldehydes 252a, d, e, h-j by an efficient and economical iron-catalyzed Pictet-Spengler reaction (Scheme 2.126) (Xu and Fan 2011). 

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