This study is the first report of electrochemical generation of hydroxyimino-cyclohexa-dien-ylidene haloniums and their application in the synthesis of new halo-N-hydroxysulfonamide derivatives. These compounds were obtained in a one-pot process based on the reaction of halonium acceptors with arylsulfinic acids. The method is easy to carry out, as it is performed using the carbon electrodes in a simple undivided cell. The protocol has a broad substrate scope with a tolerance for a variety of functional groups. The proposed mechanism is a ping-pong type reaction mechanism, which in its first stage the halonitroarene is reduced at the cathode to related hydroxylamine and in the second stage the cathodically generated hydroxylamine by oxidation at the anode and participating in disproportionation reaction is converted to the halonium acceptor.

Electrochemical reduction of different aryldiazonium salts in aqueous solution was studied. It is shown that the aryldiazonium salts are converted to the corresponding aryl radical and aryl anion.

The electrochemical generation of aryldiazonium salts from nitroarenes in a two-phase system (ethyl acetate/water) was reported for the first time. Some compounds including azo, azosulfone, and arylazides were prepared in good yields with good purity. Cathodically generated aryldiazoniums and anodically produced copper­(Ι) ions were used to perform Sandmeyer reactions. To improve the method, an H-type self-driving cell equipped with a Zn rod as an anode was introduced and used for two-phase aryldiazonium production.

In the present study, six newly synthesized 1,4-dihydropyiridine (DHP) derivatives (isopropyl 2,7,7-trimethyl-5-oxo-4-phenyl-1,4,5,6,7,8-hexahydroquinoline-3-carboxylates) (DM1-DM6) have been studied in water/ethanol mixture (50/50 v/v) by cyclic voltammetry, choronoamperometry and differential pulse voltammetry techniques at a glassy carbon electrode. A detailed oxidation mechanism is proposed. It involves an irreversible diffusion controlled one electron process followed by a disproportionation reaction resulting in the formation of a pyridine. Kinetic and thermodynamic parameters such as charge transfer coefficient (µ), number of electrons (n), exchange current density (J 0 ) and diffusion coefficient (D) were evaluated. The oxidation process is pH-dependent and the pK a of two protonated DHPs and two protonated pyridines were determined. The effect of the phenyl ring substituents on the diffusion coefficient and oxidation potential of the compounds was also studied. Furthermore, the correlation of the oxidation potentials (E ox ) of the DHPs to the highest orbital energy (E HOMO ) was investigated.