1.3.4- Oxadiazole electrochemical reduction

Oxadiazoles — see also Furazans electrochemical reduction, 5, 73 mass spectra, 6, 522... 

Electrochemical reduction of 3-phenylsydnone 89 and its 3-(4-methoxy)phenyl and 3(4-methyl)phenyl analogues represents a new method for the preparation of 2,4-dihydro-3-aryl-l,2,3-oxadiazole-5-ones <2006CCA273, 2006MI776>. The products were isolated in 82 to 88% yield, and their proposed structures are supported by melting point, elemental analysis, IR, proton NMR, and mass spectral data. 

Electrochemical reduction of the 5-(bromodifluoromethyl)-l,2,4-oxadiazole 168 in the presence of tetrakis (dimethylamino)ethylene (TDAE) generates the 5-(difluoromethyl) anion which reacts with aldehydes to give the 5-g. 

Repeated cycling through the RUB reduction wave resulted in a decrease in size of the catalytic current. This occurred even when the solution was stirred between cycles. This behavior implies that a blocking or filming of the electrode occurred during the reduction process. Repeated cycling over the oxidation wave removed the film and reactivated the electrode. The electrochemical reduction of 9,10-diphenylanthracene (DPA), 1,3,6,8-tetraphenylpyrene (TPP), anthracene (ANT), fluoranthene FLU) and 2,5-diphenyl-l,3,4-oxadiazole (PPD) in the presence of S Os - all showed similar cathodic waves. 

Olea-Azar et al. have also explored the use of 1,2,5-oxadiazole N-oxides in the treatment of Chagas disease. Spectra of radicals were obtained by both electrochemical and microsomal reduction. The calculated electron affinities of the compounds correlated well with the measured reduction potentials, which were... 

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