N-Alkylamides

Special reactions of hydrazides and azides are illustrated by the conversion of the hydrazide (205) into the azide (206) by nitrous acid (60JOC1950) and thence into the urethane (207) by ethanol (64FES(19)105Q) the conversion of the same azide (206) into the N-alkylamide (208) by ethylamine the formation of the hydrazone (209) from acetaldehyde and the hydrazide (205) and the IV-acylation of the hydrazide (205) to give, for example, the formylhydrazide (210) (65FES(20)259). It is evident that there is an isocyanate intermediate between (206) and (207) such compounds have been isolated sometimes, e.g. (211). Several of the above reactions are involved in some Curtius degradations. 

The first type is a standard polysoap derived from a polymerizable surfactant leading to poly(sodium 11-acryloyloxyundecane-l-sulfonate) PSl whereas the second polysoap is an alternating copolymer of maleic acid anhydride and acrylamide leading to a polymer with carboxylic acid groups and hydrophobic n-alkylamide groups PS2 (see Fig. 6.9). The organometaUic catalyst was not covalently bound to the polysoaps in the catalytic experiments. 

Nylon, nitrosated with dinitrogen trioxide according to Belg. Pat. 606 944 and stored cold, exploded on being allowed to warm to ambient temperature. The N-nitroso nylon would be similar in structure to N-nitroso-N-alkylamides, some of which are thermally unstable. Nylon components should therefore be excluded from contact with nitrosating agents. 

Direct nitration with anhydrous nitric acid (98%) can be accomplished most conveniently in the presence of monosubfctituted N-alkylamides. A secondary nitr-amide is then formed ... 

Tphe major objective of this work was to understand better the effect - of heavy metals in autoxidation reactions in view of the importance of trace metals in oils, fats, rubber, plastics, and other materials. Because of our interest in the stability of polyolefins such as polyethylene and polypropylene the major model substance used was 2,6,10,14-tetramethyl-pentadecane. With its four tertiary C—H bonds it is a suitable model for either polypropylene or branched polyethylene. Hexadec-l-ene was also used since its mono-olefinic character could be typical of some residual unsaturation in polyethylene. N-alkylamides served as model substances for polyamides, and a few experiments were also carried out with methyl linoleate. While studying the causes of initiation of the autoxidation of these substances we observed that certain compounds were catalysts at low concentrations but became inhibitors at higher concentrations. The phenomenon was called catalyst-inhibitor conversion. ... 

This rate equation agrees with the findings that soon after the end of the induction period the rate of oxygen uptake becomes independent of metal concentration with many catalysts (e.g., both cobalt and copper salicylaldimines or diisopropyl salicylates). By contrast cobaltous acetate had a lasting inhibitory effect in the autoxidation of N-butylacetamide and similar N-alkylamides (I). This can, however, be explained by assuming that Reaction 12 predominates over 13 in amide autoxidation since in this case the rate equation becomes ... 

There is no analogous ring opening reaction if alkali alcoxides are used and thus they may be successfully used for the preparation of pure salts of caprolactam (8, 61, 66, 68, 92, 95, 97, 103) in analogy to the preparation of sodium benzamide (11, 74, 75). Although the alcohols formed do not affect directly the salt formed, it is necessary to remove them by distillation in order to avoid side reactions taking place in the polymerization process in the presence of alcohols and esters (see below). In the same way it is possible to prepare alkali salts of other N-alkylamides e. g. benzanilide which also may be used as basic catalysts. 

The participation of nitrilium salts has also been postulated42 in the Schmidt reaction and in some Beckmann rearrangements when concentrated sulfuric acid is employed. Hill43 has demonstrated recently that some Beckmann rearrangements carried out in a concentrated sulfuric acid medium are Ritter-type reactions in which the nitrile formed in situ from the oxime combines with a carbonium ion to yield a nitrilium salt, which, when diluted with water, leads to the N-alkylamide. 

Carbamates are formed from an amine with a wide variety of reagents, of which the chloroformate is the most common amides are formed from the acid chloride. w-Alkyl carbamates are cleaved by acid-catalyzed hydrolysis N-alkylamides are cleaved by acidic or basic hydrolysis at reflux, conditions that cleave peptide bonds. 

Unfortunately yields tend to be low with N-alkylamides corresponding to 1 unsubstituted amides do not undergo this reaction. 

Reactions arising by nitrogen-halogen bond homolysis have also been reported. Examples include the photodehydrochlorination of N-chloro-N-alkylamides, the synthesis of azines (199) by irradiation of bromo-imines (200), and the pholoadditions of N-halogenoamides to alkenes and of l,4-dibromopiperazine-2,5-dione (201) to cyclohexene to give the 1 1 adduct (202) and the 2 1 adduct (203). ... 

Alkyl nitrones -> N-alkylamides. The methyl nitrones (1) derived from A4-3-ketosteroids on treatment with p-toluenesulfonyl chloride in pyridine rearrange to... 

F. Minisci, C. Punta, F. Recupero, F. Fontana, G. F. Pedulli, Aerobic oxidation of N-alkylamides catalysed by N-hydroxyphatalimide imder mild condiditons. Polar and enthaplic effects, J. Org. Chim. 67 (2002) 2671. 

W A L L A C H Imidazole Synthesis Cyclization of N-alkylamides with PCIs to imidazoles. 

Carbamoyl and a-N-amidoalkyl radicals can be easily obtained by hydrogen abstraction from formamides and N-alkylamides. They have a close analogy with acyl and a-oxyalkyl radicals. The nucleophilic character of the carbamoyl radical is explained by the fact that it can be considered an acyl radical in which the alkyl or aryl group is substituted by an amino group it can be related with resonance structures like 16... 

N-alkylamides different from formamides exclusively give rise to a-N-amidoalkyla-tion. Most of the study was accomplished with N-alkylacetamides because only the N-alkyl groups are involved in the substitution. The C—H bond in a to the carbonyl group can be also abstracted with some ease owing to the resonance stabilization 19)... 

Conformations of alkyl groups attached to the nitrogen atoms in amides have been the subject of a large number of studies, notably using nmr spectroscopy. One reason for this is the use of A7,A-dialkylamides in the early development of the dnmr technique another is the importance of N-alkylamides as simple peptide models. 

Weinreb et al have described a procedure for the preparation of acyclic N-alkylamides (110) which involves the addition of trialkylalanes (4 equiv.) to amide methylols (108 Scheme 21). While the meth-... 

N,N-Dialkylalkanamides Cyclic N-alkylamides Cyclic N-acylaminoethers N-Alkylalkanamides Cyclic amides Nitrocompounds Nitroalkanes Nitroarenes... 

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