Phenyl acetate ions, decomposition

From a study of the decompositions of several rhodium(II) carboxylates, Kitchen and Bear [1111] conclude that in alkanoates (e.g. acetates) the a-carbon—H bond is weakest and that, on reaction, this proton is transferred to an oxygen atom of another carboxylate group. Reduction of the metal ion is followed by decomposition of the a-lactone to CO and an aldehyde which, in turn, can further reduce metal ions and also protonate two carboxyl groups. Thus reaction yields the metal and an acid as products. In aromatic carboxylates (e.g. benzoates), the bond between the carboxyl group and the aromatic ring is the weakest. The phenyl radical formed on rupture of this linkage is capable of proton abstraction from water so that no acid product is given and the solid product is an oxide. 

The alkylation of quinoline by decanoyl peroxide in acetic acid has been studied kineti-cally, and a radical chain mechanism has been proposed (Scheme 207) (72T2415). Decomposition of decanoyl peroxide yields a nonyl radical (and carbon dioxide) that attacks the quinolinium ion. Quinolinium is activated (compared with quinoline) towards attack by the nonyl radical, which has nucleophilic character. Conversely, the protonated centre has an unfavorable effect upon the propagation step, but this might be reduced by the equilibrium shown in equation (167). A kinetic study revealed that the reaction is subject to crosstermination (equation 168). The increase in the rate of decomposition of benzoyl peroxide in the phenylation of the quinolinium ion compared with quinoline is much less than for alkylation. This observation is consistent with the phenyl having less nucleophilic character than the nonyl radical, and so it is less selective. Rearomatization of the cr-complex formed by radicals generated from sources other than peroxides may take place by oxidation by metals, disproportionation, induced decomposition or hydrogen abstraction by radical intermediates. When oxidation is difficult, dimerization can take place (equation 169). 

These herbicides contain nitrogen and respond to both FID and AFID. However, the analysis of these compounds is complicated by their thermal instability. For example, the total ion current trace obtained from the GC-MS ofamethanolic solution of monolinuron shows four peaks (Fig. 9). The formation of these peaks is illustrated in Fig. 10. This thermal decomposition appears to be general for the substituted ureas and reaction of substituted phenyl isocyanates with higher alcohols also occurs. As certain substituted alkyl phenylcarbamates are used as pesticides in their own right, inert solvents such as ethyl acetate or hexane should always be used for injection. The mass spectra of the thermal... 

When 8-[(4-Cyanophenyl)imino]-87f-quinazolino[3,2-c][l,2,3]benzotriazine (13) is subjected to decomposition in ethanol, acetic acid, mineral acids, or acetic acid containing iodide, bromide, or azide ions, and 2-naphthol, 4-(4-cyanoanilino)-2-[2-(substituted)phenyl]quinazolines 14 are obtained. ... 

In the first study on the decomposition of phenyl azide in the presence of electrophilic reagents it has been shown that both thermal and photochemical reactions lead to the azepinone (2) and to disubstituted arenes such as (4). The azepinone is thought to be formed by the addition of acetic acid to the didehydroazepine intermediate (1) and subsequent acetolysis, and the disubstituted arenes are formed from the nitrenium ion (3). 

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