Amines general reactions

The precipitated amine hydrochloride (or sulphate), if any, dissolves during the diazotisation to give a clear solution of the highly soluble diazonium salt. The general reaction may be written ... 

Paal-Knorr Synthesis. The condensation of a 1,4-diketone, for example, with ammonia or a primary amine generally gives good yields of pyrroles many syntheses have been reported (24). The lack of avaHabitity of the appropriate 1,4-diketone sometimes limits the usefiilness of the reaction. 

General Reaction Chemistry of Sulfonic Acids. Sulfonic acids may be used to produce sulfonic acid esters, which are derived from epoxides, olefins, alkynes, aHenes, and ketenes, as shown in Figure 1 (10). Sulfonic acids may be converted to sulfonamides via reaction with an amine in the presence of phosphoms oxychloride [10025-87-3] POCl (H)- Because sulfonic acids are generally not converted directiy to sulfonamides, the reaction most likely involves a sulfonyl chloride intermediate. Phosphoms pentachlotide [10026-13-8] and phosphoms pentabromide [7789-69-7] can be used to convert sulfonic acids to the corresponding sulfonyl haUdes (12,13). The conversion may also be accompHshed by continuous electrolysis of thiols or disulfides in the presence of aqueous HCl [7647-01-0] (14) or by direct sulfonation with chlorosulfuric acid. Sulfonyl fluorides are typically prepared by direct sulfonation with fluorosulfutic acid [7789-21-17, or by reaction of the sulfonic acid or sulfonate with fluorosulfutic acid. Halogenation of sulfonic acids, which avoids production of a sulfonyl haUde, can be achieved under oxidative halogenation conditions (15). 

The catalyst for this type of reaction is generally an amine. These reactions are quite exothermic, and the selection of the amine plays an important role in the rate of the reaction as well as in the amount of heat generated. The processes utilized to make these types of products are either batch or continuous (25—27). 

A recent adaptation of the procedure employing perchlorate and fluoro-borate salts has been reported by Leonard and Paukstelis (J5). This report includes proof of structure by direct comparison to iminium salts prepared by protonation of enamines. The general reaction reported was that of a ketone or aldehyde with a secondary amine perchlorate to give iminium salts. A large structural variety of carbonyl compounds and several amine... 

We ve already studied the two most general reactions of amines—alkylation and acylation. As we saw earlier in this chapter, primary, secondary, and tertiary amines can be alkylated by reaction with a primary alkyl halide. Alkylations of primary and secondary amines are difficult to control and often give mixtures of products, but tertiary amines are cleanly alkylated to give quaternary ammonium salts. Primary and secondary (but not tertiary) amines can also be acylated by nucleophilic acyl substitution reaction with an acid chloride or an acid anhydride to yield an amide (Sections 21.4 and 21.5). Note that overacylation of the nitrogen does not occur because the amide product is much less nucleophilic and less reactive than the starting amine. 

The treatment of acyl halides with ammonia or amines is a very general reaction for the preparation of amides.The reaction is highly exothermic and must be carefully controlled, usually by cooling or dilution. Ammonia gives unsubstituted amides, primary amines give A-substituted amides, and secondary amines give N,N-disubstituted amides. Arylamines can be similarly acylated. In some cases aqueous... 

Another hydroxylation reaction is the Elbs reaction In this method, phenols can be oxidized to p-diphenols with K2S20g in alkaline solution. Primary, secondary, or tertiary aromatic amines give predominant or exclusive ortho substitution unless both ortho positions are blocked, in which case para substitution is found. The reaction with amines is called the Boyland-Sims oxidation. Yields are low with either phenols or amines, generally under 50%. The mechanisms are not clear, but for the Boyland-Sims oxidation there is evidence that the S20 ion attacks at the ipso position, and then a migration follows. ... 

For aromatic amines, the reaction is very general. Halogen, nitro, alkyl, aldehyde, sulfonic acid, and so on, groups do not interfere. Since aliphatic amines do not react with nitrous acid below a pH of 3, it is even possible, by working at a pH of 1, to diazotize an aromatic amine without disturbing an aliphatic amino group in the same molecule. ... 

In summary, the preparation of polyimidazolinones from polyamides containing a-aminoacid units (3, X = NH) can now be considered to be a general reaction provided that Rz and/or R3 are not hydrogen. When the polyamide has additional secondary or tertiary amine functionality in the backbone, cyclodehydration appears to be exceptionally facile. In the absence of amine functionality however, a catalyst is necessary to promote cyclization. Further studies of this new heterocyclic polymer system are ongoing in our laboratories. 

The most common and least expensive catalyst for producing primaiy amines from nitriles is sponge nickel. The generalized reaction, carried out in the presence of sponge nickel catalyst, is the following ... 

Figure 2 General reaction mechanism for the ECL reaction of Ru(bpy)32+ with a tertiary amine.

Nesmeyanov has provided interesting examples of apparent intramolecular nucleophilic attack by amine on carbonyl ligands (37). Angelici (38,39) has demonstrated that amine attack on cationic metal carbonyl complexes is a general reaction resulting in the formation of carbamoyl complexes ... 

While most alkaloids do not contain aldehydes when they enter mammalian, microbial, or plant tissues, this functional group may become important when formed as a metabolite of alcohols (via alcohol dehydrogenase) or amines (via oxidative dealkylation and oxidative deamination). Aldehyde dehydrogenases catalyze oxidation of aldehydes to the corresponding carboxylic acids. The physical properties, catalytic mechanism, and specificity of this group of enzymes has been reviewed (99). The general reaction catalyzed by aldehyde dehydrogenase is seen in Eq. (9). 

Protection of Amines and Carboxylic Acids Amines and carboxylic acids can also be converted to trimethylsilyl derivatives. A general reaction is... 

The synthesis of an aromatic amine generally starts from the corresponding nitro compound. Nitration and subsequent reduction are key reactions in the synthesis of intermediates for azo pigments. 

Catalysed oxidation of primary and secondary amines generally has little synthetic value. Primary amines yield either a mixture of nitriles and amides (ca. 30%) or, in the case of arylamines, the azo derivatives (42-99%) [39], Symmetrical and non-symmetrical azoarenes are also produced in good yields ( 60%) from the reaction of acetanilides with nitroarenes under basic solidtliquid conditions, although higher yields are obtained using TDA-1 [40],... 

A kinetic smdy of the acylation of ethylenediamine with benzoyl chloride (110) in water-dioxane mixtures at pH 5-7 showed that the reaction involves mainly benzoylation of the monoprotonated form of ethylenediamine. Stopped-flow FT-IR spectroscopy has been used to study the amine-catalysed reactions of benzoyl chloride (110) with either butanol or phenol in dichloromethane at 0 °C. A large isotope effect was observed for butanol versus butanol-O-d, which is consistent with a general-base-catalysed mechanism. An overall reaction order of three and a negligible isotope effect for phenol versus phenol- /6 were observed and are consistent with either a base- or nucleophilic-catalysed mechanism. Mechanistic studies of the aminolysis of substituted phenylacetyl chlorides (111) in acetonitrile at —15 °C have revealed that reactions with anilines point to an associative iSN2 pathway. ... 

This is a fairly general reaction, and requires an amine plus an aldehyde (usually, but not necessarily, formaldehyde) together with an enolizable ketone, which together generate a P-aminoketone via an iminium system. The Mannich reaction is surprisingly... 

The preparation of furyl phosphorodichioridate is based upon a method to prepare 2-chlorofuran (16% yield, Hormi, Nasman unpublished). Later the preparation was extended to a general method to prepare furyl esters from carboxylic acid chlorides lacking a-hydrogens and alkyl furyl carbonates from primary (other than methyl) and secondary alkyl chloroformates. Phosphoryl chloride was the only acid chloride except carbon analogues found to give a furyl ester by the amine-catalyzed reaction. 

Perfluoroarenes also undergo facile and selective monosubstitution with hydroxyl-amine. This reaction is general and proceeds with different Ai-alkylhydroxylamines and a number of perfluorinated arenes (e.g. 29, equation 19) and pentafluoropyridine. 

Stork Enamine Reaction Aldehydes and ketones react with secondary amines to form compounds called enamines. The general reaction for enamine formation can be written as... 

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