Amides amination reactions

Amines are convert ed to amides on reaction with acyl chlorides Other acylating agents such as carboxylic acid anhydrides and esters may also be used but are less reactive... 

Carboxyhc acids react with aryl isocyanates, at elevated temperatures to yield anhydrides. The anhydrides subsequently evolve carbon dioxide to yield amines at elevated temperatures (70—72). The aromatic amines are further converted into amides by reaction with excess anhydride. Ortho diacids, such as phthahc acid [88-99-3J, react with aryl isocyanates to yield the corresponding A/-aryl phthalimides (73). Reactions with carboxyhc acids are irreversible and commercially used to prepare polyamides and polyimides, two classes of high performance polymers for high temperature appHcations where chemical resistance is important. Base catalysis is recommended to reduce the formation of substituted urea by-products (74). 

The chemistry of acid anhydrides is similar to that of acid chlorides. Although anhydrides react more slowly than acid chlorides, the kinds of reactions the two groups undergo are the same. Thus, acid anhydrides react with water to form acids, with alcohols to form esters, with amines to form amides, and with UAIH4 to form primary alcohols. Only the ester and amide forming reactions are much used, however. 

Conversion of Esters into Amides Aminolysis Esters react with ammonia and amines to yield amides. The reaction is not often used, however, because it s usually easier to start with an acid chloride (Section 21.4). 

Conversion of Amides into Amines Reduction Like other carboxylic acid derivatives, amides can be reduced by LiAlH.4. The product of the reduction, however, is an amine rather than an alcohol. The net effect of an amide reduction reaction is thus the conversion of the amide carbonyl group into a methylene group (C=0 —> CTbV This kind of reaction is specific for amides and does not occur with other carboxylic acid derivatives. 

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... 

This lactamization process can be promoted by enzymes such as pancreatic porcine lipase. Reduction of co-azido carboxylic acids leads to macrocyclic lactams. Although treatment of carboxylic acids with amines does not directly give amides, the reaction can be made to proceed in good yield at room temperature or... 

Lactams can be opened to -amino amides by reaction with amines at 10kbar. ° ... 

Palladium complexes also catalyze the carbonylation of halides. Aryl (see 13-13), vinylic, benzylic, and allylic halides (especially iodides) can be converted to carboxylic esters with CO, an alcohol or alkoxide, and a palladium complex. Similar reactivity was reported with vinyl triflates. Use of an amine instead of the alcohol or alkoxide leads to an amide. Reaction with an amine, AJBN, CO, and a tetraalkyltin catalyst also leads to an amide. Similar reaction with an alcohol, under Xe irradiation, leads to the ester. Benzylic and allylic halides were converted to carboxylic acids electrocatalytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions. ... 

Examples of the protection of alkynes, carboxylic acids, alcohols, phenols, aldehydes, amides, amines, esters, ketones, and alkenes are also indexed on p. xvii. Section (designated with an A 15A, 30A, etc.) with protecting group reactions are located at the end of pertinent chapters. 

Similar interchange processes may occur in other condensation polymers under suitable conditions. There is ample evidence in the literature on polyamides, and on monomeric amides as well, for the occurrence of the amine-amide interchange reaction (II)... 

Dome, M. Wakselman, M. Alkylations en milieu aqueux par les halogenures benzyliques amines ou amides II. Reactions avec quelques nucleophiles. Bull. Soc. Chim. Fr. 1975, 576-582. 

OH with acid chlorides and in turn may be converted to amides via reaction with primary amines. The conversion of N3P3C1 (NH2)2... 

N-substituted carbodiimides can react with carboxylic acids to form highly reactive, o-acylisourea derivatives that are extremely short-lived (Reaction 11). This active species then can react with a nucleophile such as a primary amine to form an amide bond (Reaction 12)... 

Dehydration (cf., 6, 648). A reagent (1), prepared in situ from (C6H5),PO and Tf20 in the molar ratio 2 1, effects dehydration, usually at 25°, of amides or oximes to nitriles in >90% yield. It also effects condensation of acids and amines to form amides. The reaction of an aryl carboxylic acid with an o-phenylenediamine promoted by 1 provides 2-arylbenzimidazoles in >80% yield (equation I). If the... 

Uses Solvent for liquids, gases, vinyl resins, wire enamels polyacrylic fibers gas carrier catalyst in carboxylation reactions organic synthesis (manufacture of aldehydes, amides, amines, esters, heterocyclics). 

These reactions also provide us with a convenient way of making secondary and tertiary amines. Thus, a primary amine may be converted into an amide by reaction with an acyl chloride, then LAH reduction... 

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