Amine with carboxylic acids

Amines are derived from ammonia by the replacement of hydrogen atoms with organic groups. Amides result from the condensation of amines with carboxylic acids. Amines and many amides take part in hydrogen bonding. 

Condensation polymerization of amines with carboxylic acids leads to the polyamides, substances more commonly known as nylons. A common polyamide is nylon-66, which is a polymer of 1,6-diaminohexane, H2N(GH2)6NH2, and adipic acid, HOOC(CH2)4COOH. The 66 in the name indicates the numbers of carbon atoms in the two monomers. 

Scheme 7.4 Enzymatic acylation of amines with carboxylic acids...

What do you think is the product of the reaction of amines with carboxylic acids They form salts with amines at room temperature. 

The clean conversion of support-bound, primary amines into sulfonamides by treatment with sulfonyl chlorides is more difficult to perform than the acylation of amines with carboxylic acid derivatives, probably because of the oxidizing properties of sulfonyl chlorides and because primary amines can be doubly sulfonylated. Weak bases (pyridine, 2,6-lutidine, NMM, collidine), short reaction times, and only a slight excess of sulfonyl chloride should therefore be used to convert primary amines into sulfonamides (Table 8.7). 

Table 13.3. Acylation of support-bound amines with carboxylic acids and carbodiimides.

The acylation of amines with carboxylic acid chlorides leads to the production of one equivalent acid, which will form a salt with unreacted amine and diminish the yield. The addition of an additional equivalent of base to neutralise this acid is a way to optimise the conditions. Normally, aqueous base is slowly added to the reaction mixture. 

Roxana I, Katsuya K (2004) Lipase-catalyzed enantioselective reaction of amines with carboxylic acids under reduced pressure in non-solvent system and in ionic liquids. Tetrahedron Lett 45 523-525... 

For instance, the reaction of amines with carboxylic acids occurs under appreciably milder conditions if phosphorus trichloride is added the reaction does not proceed by way of the intermediate acid chloride, as previously assumed, but the amine and phosphorus trichloride first form a phosphorazo compound (phosphoramidic imide) which in turn reacts with the carboxylic acid to give the amide 693... 

The reaction of amines with carboxylic acids can also be used to build heterocyclic ring systems. Aliphatic 1,2-diamines and carboxylic acids or their derivatives give imidazolines 716 boiling o-phenylenediamine with a carboxylic acid for 0.5 hour gives the 2-alkylbenzimidazole 717... 

The catalysts for cationic polymerization can be strong anhydrous acids, Lewis acids, salts of primary and secondary amines, carboxylic acids, and salts of amines with carboxylic acids that split off water at elevated temperatures. The initiators react by coordinating with and fonrung rapid pre-equilibrium lactam cations. These cations are the reactive species in the polymerizations. Initiations of this type are also possible with weakly acidic compound, but such compounds ate not able to transfer protons to the lactam. They are capable, however, of forming hydrogen bonds with the lactams. The high reactivity of the lactam cations may be attributed to the decreased electron density at the carbonyl carbon atoms. This makes them more subject to nucleophilic attacks. Protonations of the amides occur at the oxygens, but small fractions of N-protonated amides are also presumed to exist in tautomeric equilibrium. To simplify the illustrations, all lactams will be shown in this section as... 

Amides cannot be easily prepared by the direct reaction of ammonia or amines with carboxylic acids because amines function as bases to convert carboxylic acids into their unreactive ammonium carboxylate salts (Eq. 20.5). Although these salts maybe converted into amides by heating to high temperatures (>200 °C), the forcing nature of these conditions severely limits the applicability of this method (see Sec. 20.4). 

Condensation reactions between hydroxyl groups or amines with carboxylic acids or derivatives are frequently applied to the synthesis of polymers to yield polyesters and polyamides, respectively. These reactions can also be used for the preparation of hydrogels (Tomida et al., 1997 Santoro et al., 2011). 

The fimdamental reactions of an isocyanato group which proceed easily at room temperature or slightly above are reaction with (i) an aliphatic or aromatic hydroxyl group in a reactivity order primary > secondary > tertiary OH-group, and with (ii) primary or (iii) secondary amines. With carboxylic acids (iv) an amide is formed and CO2 is liberated. 

G. W. Gribble, J. M. Jasinski, J. T. Pellicone, and J. A. Panetta. Reactions of sodium borohydride in acidic media VIII. A-alkylation of aliphatic secondary amines with carboxylic acids. Synthesis, 1978, 766. 

Amides are common structures and they are important and versatile synthons to prepare pharmaceuticals, agrochemicals, materials and some specialty chemicals. Many methods have been developed to synthesize primary amides, secondary amides as well as tertiary amides. The traditional process to construct amide bond is the acylation of amines with carboxylic acid or carboxylic acid daivatives such as acid chlorides as well as anhydrides [1, 2]. Furthermore, the Schmidt reaction [3] and Beckmann rearrangement [4] also have been well developed for the amide synthesis. Recently, some reviews have been well summarized the synthesis routes of these amides [5-17]. In this chapter, we will focus on the recent progresses about amide synthesis only by N, NH, or NH2 atoms incorporation nitrogenation strategy via C-H and/or C-C bond cleavage. A series of nitrogen sources such as sodium... 

Carboie lic acids have also been utilised as electrophiles for N-alkylation. Beller reported the reaction of primary or secondary amines with carboxylic acids in the presence of a platinum catalyst and phenylsilane to directly provide the products of reductive amination. The proposed mechanism involves initial amide formation followed by reduction to the amine. A diverse range of functional groups are tolerated, including olefins, alcohols, heterocycles, and esters (Scheme 12.15). 

Amide Formation. Since the initial reports, " DCC has become the most common reagent in peptide synthesis " and in other amide bond-forming reactions of primary and secondary amines with carboxylic acids. The mechanism is considered to be well understood. - ... 

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