Alkyl-substituted amino radicals

GOWENLOCK AND SMELLING Alkyl-Substituted Amino Radicals... 

Decomposition. Just as alkyl and alkyloxy radicals can decompose to give a stable double-bonded molecule and either a hydrogen atom or methyl radical— Reactions 23 and 24—so we would expect decomposition of alkyl-substituted amino radicals to take place. 

The thermochemistry of substituted amino radicals may best be determined by the method employed for alkyl radicals—namely, measurement of the activation energy, Ej, for the forward Reaction 1, the enthalpy increase being aH. If we... 

Association with Radicals, Including Dimerization. Little evidence exists for the monoalkyl-substituted amino radicals, although this would be expected by analogy with alkyl radicals. In the pyrolysis of dimethyltriazene the two association reactions... 

An interesting method for the substitution of a hydrogen atom in rr-electron deficient heterocycles was reported some years ago, in the possibility of homolytic aromatic displacement (74AHC(16)123). The nucleophilic character of radicals and the important role of polar factors in this type of substitution are the essentials for a successful reaction with six-membered nitrogen heterocycles in general. No paper has yet been published describing homolytic substitution reactions of pteridines with nucleophilic radicals such as alkyl, carbamoyl, a-oxyalkyl and a-A-alkyl radicals or with amino radical cations. 

Lipid-Protein-Carbohydrate Interactions. Evidence for such complex interaction was recently reported by Huang et al (36) who observed that the addition of corn lipids to zein and corn carbohydrates enhanced the formation of alkylpyrazines, indicating that lipid-derived free radicals may accelerate the rate of Maillard reactions. Two of the alkylpyrazines, identified in such mixtures after heating for 30 minutes at 180°C, have 5-carbon alkyl substitution at the pyrazine ring and could only be explained by interaction of lipid or lipid decomposition products. These authors suggested that condensation of amino ketones, formed by protein-carbohydrate interaction, may yield 3,6-dihydropyrazine which would in turn react with pentanal, a lipid oxidation product, to form 2,5-dimethyl-3-pentylpyrazine. 

Indoles can be used as radical acceptors instead of 63 [120, 121]. Simple and twofold reactions giving either 3-alkylindoles [120] or l,l-bis(3-indolyl)alkanes [121] were observed in 16-72% and 54-90% yield, respectively. In both methods the indole is subject to radical addition in 3-position. The resulting a-amino radical undergoes a further oxidation and deprotonation to the 3-substituted indole. In the case of twofold additions, the second indole unit is introduced by a subsequent polar Friedel-Crafts-type alkylation. 

Thermochemical data for alkyl amino radicals show for alkylhydrazines a trend in D (N-N) for these compounds in which the N-N bond was strengthened by increasing the degree of substitution by methyl in NH2 NH2 . From these values it was possible to determine values for the enthalpies of formation of the alkylamino radicals , and to confirm these by electron impact studies. The latter values were found to be in agreement with those obtained from pyrolysis studies. Hydrazine has often been used as a source of amino radicals by pyrolysis flame decomposition shock tube decomposition , electrodeless discharge and microwave discharge , viz. 

As aniline, toluidine, xylidine, etc., are primary amines if we substitute alkyl or aryl radicals for one or both of the remaining amino hydrogen atoms we shall obtain secondary and tertiary amines. Such products may be typified by the following in which the methyl and phenyl radicals are substituted for the amino hydrogen in aniline. 

A study of the effect of the structure and size of the amine radical (butylamine, dibutylamine, hexylamine, piperidine, aniline) on its reactivity in the nucleophilic replacement of tosyloxy groups in cellulose tosylate has shown (29) that this reactivity depends primarily on the basicity of the amine. This assumption was confirmed by a study of the interaction of cellulose toxylates of different degrees of substitution (DS from 0.3-1.7) wit iminodiacetic and anthranilic acids (30, 31). The degree of substitution of the reaction products with respect to the N-carboxyalkyl(aryl)amino groups was found to be lower than that of the corresponding N-alkyl(aryl)amino derivatives. 

CAS 68649-05-8 EINECS/ELINCS 272-021-5 Synonyms 3-Aminobutanoic acid, n-coco alkyl derivs. Butanoic acid, 3-amino-, N-coco alkyl derivs. N-Coco-3-aminobutyric acid Classification Substituted amino acid Formula R-NH-CFICFI2COOFICH3, R represents the coconut radical Properties FILB 13.6 amphoteric Toxicology TSCA listed... 

Information about the relative kinetic acidities of aminium radicals has also come from a number of studies probing product distributions of SET-promoted photochemical reactions. One of the earhest investigation in this area was conducted by Cohen and co-workers, in which product distributions of SET-induced photoreactions of unsymmetrically substituted tertiary amines were used to gain information about how alkyl substituents affect the rates of aminium radical a-CH deprotonation. Irradiation of solutions of 4-benzoylbenzoic acid containing a variety of tertiary amines leads to formation of dealkylation products (Scheme 9). In these processes, the initially formed aminium radical 10 transfer a proton to the 4-benzoylbenzoic acid anion radical to generate an a-amino radical, which then donates an electron to another 4-benzoylbenzoic acid molecule. Hydrolysis of iminium ions 11, formed in this manner, then gives carbonyl and secondary amine products. The results of these studies qualitatively indicate that dealkylation occurs preferentially at the less alkyl-substituted a-carbon. 

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