Acetophenone, electrochemical oxidation

Usually, electrochemical oxidative hydrolysis of ketoximes affords the corresponding ketones. Hence, 2-octanone (equation 13) and acetophenone were obtained from the corresponding ketoximes in 90% and 97% yields, respectively. However, camphor oxime was transformed into the ring-cleaved nitrile (equation 14). ... 

Cleavage of oximes to the parent carbonyl compound may be performed under mild conditions by anodic oxidation in CH3CN/H2O [123]. Thus, anodic oxidation of 4-sub-stituted acetophenone oximes in wet acetonitrile furnishes the corresponding acetophenones in high yields, while the oxidation of benzaldoximes is unselective [124] [Eq. (18)]. By indirect electrochemical oxidation using the Mn(II)/Mn(III) mediator system in the... 

The air-oxidation of 1-phenylethanol to acetophenone in an aqueous alkaline solution has been chosen as a model reaction. The catalytic experiments were completed with the application of an in-situ electrochemical method for studying catalyst deactivation and the role of promoters. The potential of the catalyst, which was considered as a slurry electrode, was measured during the oxidation reaction. More details of the method can be found elsewhere 13,14). 

For the asymmetric reduction of ketone and aldehyde derivates, two electrochemical reduction systems using ADH as catalyst were examined (Fig. 22) [108]. In system A, the reduced coenzymes are regenerated using either FNR for NADPH or DP for NADH. Methyl viologen serves as electron mediator between the electrode and FNR/DP. System B contains ADH as sole enzyme, which catalyzes both reduction of substrates and regeneration of cofactors. Phenylethanol is oxidized by ADH accompanied by reduction of NADP+ to NADPH and its oxidation product acetophenone is reduced electrochemically at a glassy carbon cathode. 

Low-potential electron-transfer mediators such as viologens can substitute natural cofactors (particularly NADH) in some enzymatic reactions [184], The electrochemical reduction of viologens has been studied extensively [185] and they and other reductive electron mediators have been utilized to drive enzyme-catalyzed reactions [186], For instance, the electrochemical reduction of NAD(P)+ to NAD(P)H with a current efficiency of more than 97 % was achieved using alcohol dehydrogenase in the presence of acetophenone as an electron mediator [187], The addition of acetone or acetaldehyde as a substrate to the above bioelectrocatalytic system allowed the reduction of the substrate to the corresponding alcohol at alcohol dehydrogenase accompanied by the oxidation of the resulting NAD(P)H. 

As well as these epoxidation reactions, several oxidation reactions have also been reported in ionic liquids, including the oxidation of aromatic aldehydes to acids, of alcohols to aldehydes or ketones, of styrene to acetophenone or styrene carbonate and of benzyl alcohols. " Ionic liquids exhibit great stability toward oxidants, as has been demonstrated in electrochemical studies, leading to an ever-growing number of publications. 

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