Anilines Experimental Procedure

Treatment of aniline 1 with nitric acid in the presence of tetrafluoroboric acid leads to a relatively stable benzenediazonium tetrafluoroborate 2 by the usual diazotization mechanism. There are several variants for the experimental procedure. Subsequent thermal decomposition generates an aryl cation species 4, which reacts with fluoroborate anion to yield fluorobenzene 3 " ... 

Primary aromatic amines (aniline, 3-toluidine, 4-anisidine and 3-chloroanilinc) react with 4 to give 2-[2-(arylamino)-l-cyanoviny]]benzimidazoles9 (see Houben-Weyl, Vol.E8c, p 314 with an experimental procedure).289... 

Wang et al. reported two different reaction conditions for a solvent free Friedlander quinoline synthesis. Initially, they reported the reaction of 2-acetyl anilines 73 with a variety of P-diketoesters 74 using / -Ts()H as the catalyst under microwave conditions to form substituted quinolines 75 <060BC104>. They also reported the same reaction using BiCl3 as the catalyst under thermal conditions <06LOC289>. Both sets of conditions afford high yields and simpler experimental procedures. 

The experimental procedure can be varied by the use of reagents which will give biguanides in situ and thus form the required triazine. Examples include 493, 554) the interaction of arylamines (e.g. p-chloro-aniline hydrochloride) and cyanoguanidine, followed by acetone and hydrochloric acid. Acetone may be replaced by its bisulphite compound, by diethyl acetal or by isopropenyl acetate, but p-chlorophenylbiguanide fails to condense 113) with acetone diethyl acetal at 130°. Under the correct acid conditions, the isomeric p-chloroanilino-triazine (CXXV) is not formed on the other hand, the free p-chlorophenylbiguanide base did not react with acetone in the absence of a catalyst. 

The experimental procedure was essentially the same for all substances mentioned, namely, the method used in the case of nitrobenzene. Some complication arises, however, due to the fact that the solids do not disperse as easily in the fermentation mixture. Although the materials were always added in alcoholic solution to the yeast preparation, partial precipitation was unavoidable. With 21.4 g. of nitrosobenzene a yield of 4 g. of aniline was obtained addition of the same quantity of phenylhydroxylamine gave 7.5 g. of aniline. In both cases azobenzene appeared as a by-product and could be isolated in the pure state. Its formation can be readily explained by a condensation of the intermediary nitrosobenzene with the end product aniline. 

Wang resin bound 4-nitrophenyl carbonate is a convenient intermediate for the attachment of amines to polystyrene as carbamates (see Experimental Procedure 14.2). Aliphatic amines [82-87], ammonia [88], and amino acids [89] react exothermically with this support, whereas anilines generally require catalysis and/or long reaction times (Entry 3, Table 14.7). For the immobilization of anilines as carbamates, Wang resin derived chloroformate [90-92] generally leads to better results than resin-bound 4-nitrophenyl carbonates. Amidines also react with polystyrene-bound 4-nitrophenyl carbonates to yield /V-alkoxycarbonyl amidines (Section 3.9 [93-95]). Support-bound alkoxycarbonyl hydrazines can be prepared by treating polystyrene-bound phenyl carbonates with hydrazine [96-98]. 

The usual experimental procedure is exemplified in the preparation of iodobenzene from aniline detailed in Organic Syntheses.1221... 

In macroscopic chemistry, the experimental procedures for the bromination of aromatic compounds depend greatly on the nature and reactivity of the starting material. Activated aromatics such as phenol and aniline can be brominated to the tri-and tetrabrominated derivatives by using dilute aqueous solutions of bromine, whereas a controlled monobromination is very challenging and often requires cryogenic conditions. On the other hand, thermally controlled brominations of less activated aromatics such as toluene are rather slu ish reactions. Th often require photoinitiation and the use of Lewis adds as catalysts. 

Although benzene (4) is a potential starting point of our synthesis (Scheme 21.4), it is an alleged carcinogen, so the sequence of reactions begins with nitrobenzene (5). Discussion of and experimental procedures for the reduction of nitrobenzene and the conversion of aniline (6) to acetanilide (7) are found in Section 21.2, so the present description starts with the bromination of acetanilide. 

Aniline, intercalation in layered protonic conductors, 220-229 Aromatic polycyclic molecules, use as probe molecules for mechanistic studies of sol-gel-xerogel transitions and cage properties, 400 Artificially layered ceramics, nanoscale, electrodeposition, 244-253 Asymmetrically layered zirconium I iqtonates, 166-176 experimental procedure, 174-176 interlayer spacings of compounds, 170r schematic representations of layers, 169/ synthesis, 167-168... 

ABSTRACT. Detailed experimental procedures are given for the chemical synthesis from aniline of analytically pure emeraldine hydrochloride, a highly conducting polymer derived from the emeraldine oxidation state of polyaniline, which contains equal numbers of oxidized and reduced repeat units, the non-protonated base form of which has the composition,... 

Another common approach consists of the comparison between the experimental rate constants and theoretical values calculated by the procedure developed by Marcus (1956), Marcus and Sutin (1985) as well as Hush (1958). This classical procedure is used widely. Premsingh et al. (2004) gave the relevant references and described a detailed procedure to analyze the ion-radical reaction between anilines and chromium (V) complexes of azomethyne derivatives. Lepage et al. (2003) studied transformation of para-substituted thioanisoles to corresponding methylarylsulfoxides... 

Window diagrams and related methods may in principle be applied to optimization problems in more than one dimension. The main difference compared with one-parameter problems is that graphical procedures become much more difficult and that the role of the computer becomes more and more important. Deming et al. [558,559] have applied the window diagram method to the simultaneous optimization of two parameters in RPLC. The volume fraction of methanol and the concentration of ion-pairing reagent (1-octane sulfonic acid) were considered for the optimization of a mixture of 2,6-disubstituted anilines [558]. A five-parameter model equation was used to describe the retention surface for each solute. Data were recorded according to a three-level, two-factor experimental... 

The described procedure essentially follows that described by Meerwein et al.2 as modified slightly by Yale and Sowinski.4 This same method can be used for a great variety of substituted anilines with good results. As evident in Table I, good yields are obtained in most cases, and the reaction works better for anilines with electron-withdrawing substituents. The identical procedure has been used to prepare many other examples, such as m-F, o-F, 3,5-di-CF3.5 This method readily provides many unavailable arylsulfonyl chlorides it is experimentally straightforward, and the products are isolated without complications. 

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