Allylic amines, deamination

Deaminates benzylic and allylic amines, converts acid hydrazides to isocyanates. Cryst. Mp 270-272°. Tetrafluoroborate ... 

In the buffered hydrolysis of N-methyl-4-(chrysanthemyloxy)-pyri-dinium iodide (16-OPy-hI ), a leaving group which is expected to minimize internal return, the naturally occurring allylic isomers, artemisia and yomogi alcohols (18 and 19) are the major products, but a small amount (0.5%) of santolina alcohol (17) is present (66, 67). Similar results have been reported for amine deamination (69) and dinitro-benzoate solvolysis (66, 67, 70). The absolute configuration of natural santolina alcohol corresponds to that of chrysanthemic acid, as predicted by the Bates and Paknikar biogenesis (73). 

Deamination of the corresponding amine gives the allylic alcohol resulting from iQ dride shift as the main product and an increased amount of the cyclization product. 

Aryl alcohol oxidase from the ligninolytic fungus Pleurotus eryngii had a strong preference for benzylic and allylic alcohols, showing activity on phenyl-substituted benzyl, cinnamyl, naphthyl and 2,4-hexadien-l-ol [103,104]. Another aryl alcohol oxidase, vanillyl alcohol oxidase (VAO) from the ascomycete Penicillium simplicissimum catalyzed the oxidation of vanillyl alcohol and the demethylation of 4-(methoxymethyl)phenol to vanillin and 4-hydro-xybenzaldehyde. In addition, VAO also catalyzed deamination of vanillyl amine to vanillin, and hydroxylation and dehydrogenation of 4-alkylphenols. For the oxidation of 4-alkylphenol, the ratio between the alcohol and alkene product depended on the length and bulkiness of the alkyl side-chain [105,106]. 4-Ethylphenol and 4-propylphenol, were mainly converted to (R)-l-(4 -hydroxyphenyl) alcohols, whereas medium-chain 4-alkylphenols such as 4-butylphenol were converted to l-(4 -hydroxyphenyl)alkenes. 

The enzyme found in the liver will deaminate secondary and tertiary aliphatic amines as well as primary amines, although the latter are the preferred substrates and are deaminated faster. Secondary and tertiary amines are preferentially dealky la ted to primary amines. For aromatic amines, such as benzylamine, electron-withdrawing substituents on the ring will increase the reaction rate. The product of the reaction is an aldehyde (Fig. 4.30). Amines such as amphetamine are not substrates, seemingly due to the presence of a methyl group on the a-carbon atom (Fig. 4.27). Monoamine oxidase is important in the metabolic activation and subsequent toxicity of allylamine (Fig. 4.31), which is highly toxic to the heart. The presence of the amine oxidase in heart tissue allows metabolism to the toxic metabolite, allyl aldehyde (Fig. 4.31). Another example is the metabolism of MPTP to a toxic metabolite by monoamine oxidase in the central nervous system, which is discussed in more detail in chapter 7. 

The deamination of the allylic 3-aminocholest-4-enes is rather remarkable in that the products are not derived from an intermediate delocalised allylic cation 14) [20]. Other cholest 4-en-3-yl derivatives solvolyse to give the allylic cation (14) irrespective of the original C(3)"Configuration, and the cation affords a characteristic mixture of cholesta-3,5-diene and cholest-4-en-3a yl and -SjS-yl derivatives (p. 381). The 3(S-amine (10), however, gave only cholest-4-en 3 -ol (ii) on deamination, whereas the 3a-amine (12) gave cholesta-2,4-diene (13) [20], Both amines therefore react in the same... 

Changes in stereochemistry of the type under consideration might be expected to have a parallel in reactions involving allylic systems. The products of deamination of the isomeric butenyl- and pentenyl-amines in acetic acid and in aqueous solution, shown in Table 5, offer some... 

The Solvent Dependence of Deamination of Allylic Pentenyl- and Butenyl-Amines"... 

Many oxidative processes (e.g., benzylic, allylic, alicyclic, or aliphatic hydroxylation) generate alcohol or carbinol metabolites as intermediate products. If not conjugated, these alcohol products are further oxidized to aldehydes (if primary alcohols) or to ketones (if secondary alcohols). Aldehyde metabolites resulting from oxidation of primary alcohols or from oxidative deamination of primary aliphatic amines often undergo facile oxidation to generate polar carboxylic acid derivatives." As a general rale, primary alcoholic groups and aldehyde functionalities are quite vulnera-... 

Cyclobutanol was obtained by deamination of (cyclopropylmethyl)amine in 40% yield. Cyclopropylmethanol was a major byproduct in this reaction. A more efficient synthesis of cyclobutanol is the acid-catalyzed rearrangement of cyclopropylmethanol with aqueous hydrochloric acid " cyclobutanol was obtained in 72% yield containing a trace of the allyl alcohol. This transformation forms the basis of an efficient cyclobutene synthesis. ... 

Deamination. Benzylic or allylic primary amines (1) can be deaminated as depicted in equation (I). The pyrolysis step, (4) -s- (5), may be a retro-ene reaction. 

Dehydrogenation of amines may be achieved by thermolysis of sulphinamides, although benzylic or allylic activation is required to control the regioselectivity of elimination (Scheme 1)/ A biomimetic oxidative deamination of primary... 

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