Electrochemical reduction of nitrotetralones

The electrochemical reduction of three nitrotetralone derivatives by tast and differential pulse polarography and cyclic voltammetry in a wide pH range was studied. In aqueous media, the reduction of mono- and dinitrotetralone follows the general pattern of reduction of aromatic nitro compounds: the nitro group is reduced in a four-electron step to a hydroxylamine group. However, in mixed media this reduction differs from that of other nitrobenzenes, due to the fact that the formation of the nitroradical anion was not observed. The reduction of the acetoxy derivative was studied only at alkaline pH, because it suffered acid hydrolysis. The ionization pK of the protonatable groups were polarographically obtained.     

Electrochemical reduction of diazepam

The reduction of 7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepine-2-one at the dropping mercury electrode has been investigated. The process is diffusion controlled; furthermore, the reduction wave enables the quantitative determination of the drug both in acid and basic media. The reagent captures two electrons and two hydrogen ions. A disproportionation reaction of the hydrazo-compound takes place, and amines are the final reduction products.     

Electrochemical reduction of N-vinylazoles

Classical polarography inaprotic solvents was used to study the reduction of N-vinyl derivatives of pyrazole, imidazole, 1,2,3- and 1,2,4-triazoles, and tetra-zole. The N-vinylazoles studied were reduced in acetonitrile by a one-electron mechanism with subsequent dimerization of the radical-anions formed. The N-vinyl derivatives of pyrazole, imidazole and tetrazole were reduced analogously in DMF, while N-vinyltriazoles in DMF are reduced by a mixed mechanism with predominant two-electron transfer. Possible schemes for the electrochemical reduction of N-vinylazoles are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 315–319, March, 1986.     

Electrochemical reduction of N-nitroaminotetrazoles

The electrochemical reduction of 5-nitroamino- and 2-methyl-5-nitroaminotetrazoles at the first wave potential consumes six electrons, while the reduction at the second wave potential consumes eight or nine electrons. The preparative reduction of 2-methyl-5-nitroaminotetrazole at the second wave potential leads to 2-methyl-5-aminotetrazole and ammonia. A mechanism is proposed for these reactions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 944–946, July, 1992.     

Electrochemical metalloporphyrin-catalyzed reduction of chlorite

We measured the redox stoichiometry and rate constants for the electrochemical reduction of ClO(2)(-) at pH 7, catalyzed by a series of metalloporphyrins of Mn, Fe, and Co with different proximal and distal environments. A clean four-electron reduction was observed. The catalytic activity correlates well with that observed in reduction of H(2)O(2). The axial imidazole and/or a redox-active distal metal (Cu or Co) increases the turnover frequency in several compounds. The metalloporphyrins were inert to ClO(x)(-) (x = 3,4) and IO(3)(-) but catalyzed facile two-electron reduction of IO(4)(-); six-electron reduction of BrO(3)(-) was also observed.     

Electrochemical reduction of bipyridinium salts

The N,N-aryl substituted bipyridinium perchlorates were studied by the methods of cyclic voltamperometry and classical and commutated polarography in DMFA. It was shown that cation-radicals, which are stable in an atmosphere of argon, are formed at the first stage of reduction. The reversibility and the number of the subsequent stages depend on the nature of the substituent at the nitrogen atom. The formation of the bipyridinium cation-radicals was confirmed by the method of EPR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 626–629, May, 1986.     

Electrochemical reduction of triphenyl phosphate

The electrolytic reduction of triphenyl phosphate proceeds with the participation of tetrabutylammonium cations with the formation of butyl diphenyl phosphate in DMF. It was concluded that the step involving electron transfer to the triphenyl phosphate molecule has retarded character.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1279–1283, June, 1990.     

Electrochemical and chemical reduction of pyridyl-substituted pyrrolidinofullerenes

Using cyclic voltammetry, it is shown that formal reduction potentials of pyridyl-substituted pyrrolidinofullerenes are shifted to negative values as compared with formal potentials of the corresponding redoxtransitions of C₆₀, which indicates weakening of the acceptor properties of the fullerene fragment. NIR spectrophotometric and EPR spectroscopic studies show that cis-2′,5′-di-(4-pyridinyl)pyrrolidino-[3′,4′:1,2][60]fullerene is reduced with 1,8-diazobicyclo[5.4.0]undec-7-ene and morpholine to give a radical anion.     

Electrochemical selective reduction of 2,4-dinitrochlorobenzene

Electrochemical behavior of 2,4-dinitrochlorobenzene was studied using the method of preparative electrolysis in an acidic medium. The effect of the cathode material, temperature, nature of the solvent, concentrations of the initial dinitro compound and hydrochloric acid on the current efficiency of chloronitroanilines and their ratio was studied. Conditions of electrosynthesis of chloronitroanilines with predominant content of 2-chloro-5-nitroaniline (72–76 %) in the reaction solutions are found providing the yield of chloronitroanilines of 83–86% and the current efficiency of about 100%.     

Electrochemical reduction of arenechromium tricarbonyl complexes

Conclusions A study was made of the electrochemical reduction of some -ArCr(CO)₃ complexes at a mercury dropping electrode in dimethylformamide on a support of 0.1 NEt₄NClO₄ solution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 471–473, February, 1975.     

Electrochemical reduction of heterocyclic enammonium salts

Four N,N-disubstituted 2-cyano-Δ⁷-hexahydroindolium salts, 1, have been reduced at a mercury cathode in aqueous buffered solutions at intermediate pH-values. From the catholyte the following products were isolated and identified: 2-(β-cyanoethyl)-cyclohexanone, 5, a secondary amine, 4, and a mixture of cis-trans isomeric tertiary 2-(β-cyanoethyl) cyclohexylamines, 6. A reaction path via the protonated enamine 3 is proposed based on the pH-dependence of the composition of the product mixture and a few reductions in DMF solution.     

Electrochemical reduction of bifunctional organic compounds

Russian Chemical Bulletin -     

Organo-silanes and -germanes with chelated and/or non-chelated oxinato ligands

Several tri- and di-organo(oxinato)-silanes and -germanes have been prepared from corresponding organo-silazanes or -germazanes. The UV spectra indicate that the compounds involve either chelated or non-chelated oxinato groups or both depending on the number and kind of organic groups on the metal atom. The PMR spectra of RR′Si(OX)₂ (R = alkyl, R′ = vinyl or phenyl) are interpreted in terms of rapid exchanges between the two kinds of oxinato groups