Nitrated derivs of aniline

The twisting from the plane in some high nitrated derivatives of aniline was examined by Kamlet and co-workers [15]. 

Aniline, Polynltro Derivatives. As no info is available on the analysis of these compds, we asked the opinion of Mr, F. Pristera and Dr H. Walter, who had wide experience in analysis of polynitro derivs of toluene, phenol, etc. If the sample is a solid, its mp must be detd and if it is a liquid, its bp. Next comes the analysis by lR(if an apparatus is available). Experiments at PicArsn showed that IR spectrograms of various nitrated derivs of toluene permitted distinguishing, not only the degree of nitration but also the position of NOa groups (Refs 13 14). In later work spectrograms of o- and p-nitroanilines [See paper by F. Prist era et al published in Anal Chem 32, 497(1960)] showed distinct differences between these two compds. 

Nitro derivatives of aniUne (Vol, I, p. 556). With the exception ofhexanitro- diphenylamine nitro derivatives of aniline are not in use as explosives. Some of them are intermediates of reactions leading to higltly nitrated compounds by oxidation NH, — NOj according to the method of Nielsen. Coon et al. [10. 16]. See also (38). 

Muspratt and Hofmann reduced nitrobenzene to aniline by Zinin s method, and nitrotoluene to toluidine, mentioning that aniline cannot be nitrated but nitraniline can be obtained by reducing dinitrobenzene, a reaction later described in detail. Hofmann s paper on the chloro- and bromo-derivatives of aniline has a note by Liebig certifying the accuracy of the work. Hofmann and Muspratt s toluidine was a mixture of ortho- and para-toluidine. Pure orthotoluidine was first obtained by A. Rosenstiehl, metatoluidine by Beilstein and A. Kuhlberg, and paratoluidine by Hofmann. ... 

Amatol was a mixture of TNT and ammonium nitrate, as discussed below. Tetryl was trinitrophenylmethylnitramine, a derivative of aniline. 

Mono-substitution products of primary amines cannot easUy be prepared by direct action of the appropriate reagent for example, bromination of aniline yields largely the 2 4 6-tribomo derivative and nitration results in much oxidation. If, however, the amino group is protected as in acetanilide, smooth substitution occurs. Thus with bromine, />-bromoacetanilide is the main product the small quantity of the ortlio isomeride simultaneously formed can be easily eliminated by crystallisation. Hydrolysis of p-bromoacetanilide gives/ -bromoaniline ... 

Replacement of the remaining ether oxygen by basic nitrogen leads to a compound that shows anti-malarial activity. Nitration of aniline derivative 38 leads to substitution para to the alkyl group. (Protonation of the amine under the reaction conditions leads to deactivation of the position para to that group relative to that para to alkyl. The position meta to the protonated amine is less deactivated.)... 

To get a complex set of substituents by direct derivatization of benzotriazole is not feasible. In such situations, it is better to have all the substituents in place first and later construct the heterocyclic ring. High reactivity of anilines and their well-developed chemistry makes them good stating materials. In an example shown in Scheme 215, acetanilide 1288 is nitrated to afford nitro derivative 1289 in 73% yield. Catalytic reduction of the nitro group provides methyl 4-acetylamino-3-amino-5-chloro-2-methoxybenzoate 1290 in 96% yield. Nitrosation of compound 1290 in diluted sulfuric acid leads to intermediate 1291, which without separation is heated to be converted to 7-chloro-4-methoxy-l//-benzotriazole-5-carboxylic acid 1292, isolated in 64% yield <2002CPB941>. 

The chemical character of a compound is not fundamentally altered by the introduction of a nitro-group. Thus the ring-substituted nitro-derivatives of the hydrocarbons are neutral compounds like the hydrocarbons themselves. If, however, a nitro-group enters a substance having, for instance, an acid character, then this character is thereby intensified the nitrophenols, for example, are more acidic than phenol. Correspondingly, the strength of bases is decreased by nitration the nitranilines are less basic than aniline. 

A number of other amines containing electron-withdrawing groups undergo facile N-nitration (Table 5.1). The direct A-nitration of aniline derivatives is limited to amines of... 

Coburn also reported the synthesis of BPAF (41), the 3,4-bis-picrylamino derivative of furazan. Thus, reaction of two equivalents of aniline with 1,2-dichloroglyoxime (38) yields the bis-aniline (39), which on treatment with sodium hydroxide in ethylene glycol undergoes cyclization to the furazan (40), and nitration of the latter with concentrated nitric acid at room temperature yields BPAF (41). 

Ammonium salts contain a nitrogen atom with four bonds that has a positive charge. Four-bonded nitrogen atoms derived from amines are ammonium ions (if they re derived from aniline, they re anilinium ions). If the four bonds are all to carbon atoms, the nitrogen atom is quaternary. Salts contain a cation (named first) and an anion (named last). Typical anions include Cl (chloride), Bi" (bromide), HSO (hydrogen sulfate or bisulfate), and NOj-(nitrate). Figure 13-5 shows two examples of ammonium ions. 

Aniline is an important derivative of benzene that can be made in two steps by nitration to nitrobenzene and either catalytic hydrogenation or acidic metal reduction to aniline. Both steps occur in excellent yield. Almost all nitrobenzene manufactured (97%) is directly converted into aniline. The nitration of benzene with mixed acids is an example of an electrophilic aromatic substitution involving the nitronium ion as the attacking species. The hydrogenation of nitrobenzene has replaced the iron-... 

As a starting material for the preparation of sym-trinitrotriazidobenzene, 1,3,5-trichlorobenzene is used. It is obtained by the chlorination of aniline and the removal of the amino group. Nitration to the trinitro derivative is described in Vol. I. The final reaction is simple powdered 1,3,5,-trichloro-2,4,6-trinitrobenzene is added to an aqueous alcohol solution of sodium azide. The precipitated product is washed with alcohol and water and dried at a moderate temperature. The product so obtained may be purified by crystallization from chloroform. 

SAMPLE SOLUTION (a) Because direct nitration of aniline is not a practical reaction, the amino group must first be protected as its A/-acetyl derivative. 

The nitration of aniline in the presence of a large amount of strong sulfuric acid results wholly in the formation of m-nitro-aniline, but the similar nitration of dimethylaniline gives principally a mixture of the ortho- and para-derivatives. Mono-methylaniline stands between aniline and dimethylaniline in respect to the orienting effect of its amino group it yields a considerable amount of the m-nitro- compound—and dimethylaniline is preferred for the preparation of tetryl. Commercial dimethylaniline contains a certain amount of monomethylaniline, from which it is extremely difficult to free it, and this in the manufacture of tetryl is converted in part into 2,3,4,6-tetranitro-phenylmethylnitramine, or m-nitrotetryl, pale yellow, almost white, crystals from benzene, m.p. 146-147.087... 

Aniline is an important derivative of benzene that can be made in two steps by nitration to nitrobenzene and either catalytic hydrogenation or acidic metal reduction to aniline. 

The nitration of amines results partly in the formation of ring nitrated compounds and partly in formation of nitro derivatives of phenols. For example from aniline small quantities of p- nitroaniline were obtained along with 2,4-di-nitrophenol as the principal product. 

---