Oxidation of primary, nitramine anions RNNO2-Bu~N + (R = ,'vie, Et, Pr i, or methoxyfurazanyl) in 0.1 N BuzNCIO a in MeCN on a Pt anode was studied by voltammetry and controlled potential electrolysis. It was found that the first stage of oxidation affords the corresponding radicals, which are further stabilized due to hydrogen abstraction from the medium. These radicals are also involved in other reactions, includi~g those, which yield azo derivatives. The possibility of generation of nitrene species in these reactions is discussed.Key words: electrooxidation of nitramine anions, nitrenes, azo compounds.Previously. I we examined the possibility of cathode deprotonation of primary, nitramines. As part of continuing studies of the electrochemical behavior of nitramines, in the present work we studied the regularities of electrooxidation of nitramine anions containing a donor or acceptor substituent at the amine nitrogen atom. Judging from the published data, these processes are still poorly understood. However, radical intermediates, which are probable intermediates in the oxidation of nitramine anions, could be considered as potential sources of nitrene species. ExperimentalThe voltammetric measurements were carried out in a temperature-controlled (25 ~ glass cell with cathode and anode compartments separated by a porous-glass filter. The polarization curves were recorded on a rotating disk Pt electrode (7.61 -10 -3 cm 2) using a P-5827M potentiostat. A graphite rod was used as the auxiliary, electrode and Ag/0.1 N AgNO 3 was used as the reference electrode.The coulometric measurements and microelectrolysis were carried out in the same cell. A platinum plate (2 cm 2) was used as the working electrode, but the polarization curves were recorded in the course of electrolysis using a rotating disk Pt electrode.The preparative electrolysis was performed ma sealed cell analogous to that described above (but of a la~er volume). A Pt plate (28 cnt 2) was used as the anode. The auxiliary and r:efei'ence ek/~:frodes were the san'ie as those used in the voltammetric measurements.A 0.1 N Bu4NCIO 4 solution in anhydrous MeCN was used as the supporting electrolyte in the voltammetric measurements and in the electrolysis. The working solution was deaerated with argon before the polarization curves were recorded and the electrolysis was performed.Dehydration of MeCN was performed by distillation over P205 (five times) followed by distillation over calcined K2CO 3.Methyl-, ethyl-, and isopropylnitramines were prepared according to procedures reported previously, z,3 Tetrabutylammonium salts of the above-mentioned nitramines were prepared by adding an equimolar amount of KOH to their methanolic solutions followed by cation exchange upon addition of the calculated amount of tetrabutylammonium perchlorate. The alkali salts were precipitated with acetone, the filtrates were concentrated in vacuo, and the residues were recrystatlized from organic solvents. 4-Amino-3-methoxyfurazan was prepared according to a known procedure. 't A proc...
Functional organization of the central nervous system (CNS) relies upon a fine interplay between two principal processes involved in nervous activity: excitation and inhibition. Violation of this interaction leads to the development of cerebral pathologies. Both the excitation and inhibition processes are mediated by intercell and intracell chemical neurotransmitters (endogenous ligands). In particular, interference with the neuromediator function of only g-aminobutyric acid (GABA) causes a number of pathologies, primarily convulsive states, determining the symptomatics of disorders such as epilepsy, drug intoxication (strychnine, corazole, bemegride, novocain, organophosphorus compounds, insecticides, etc.), infectious diseases (meningitis, toxic influenza, tetanus, etc.), cerebral traumas, brain edemas, and others. In practice, such convulsions can be arrested using drugs belonging to various pharmacological groups, including pure anticonvulsants, barbiturates, bromides, tranquilizers, hypnotics, etc., which are ca-pable of preventing the development or decreasing the intensity of convulsions, reducing the frequency of attacks, or eliminating the accompanying disturbances (loss of consciousness, behavioral and vegetative disorders, etc.).However, the group of anticonvulsants presently administered in practice contains no one highly effective drug of universal use. This is related not only to the variety of forms of the convulsive states, but also to the complexity of interactions between neuromediator systems, primarily those of inhibiting (GABA) and exciting amino acids [1 -5]. The continuous search for new anticonvulsants (see, e.g., [6 -20]) needs no additional justification. This paper addresses certain features and rules in the search for compounds possessing anticonvulsant activity.Biochemical disorders in CNS, which are capable of inducing the development of convulsions, include changes in (i) the transmembrane concentration gradients of sodium, potassium, calcium, and chlorine ions (factors providing for the membrane rest and action potentials), (ii) the energy balance in neurons, and (iii) the level and metabolism of synaptic mediators including GABA, glutamic and asparagic acids (ex-
Carbamic acid derivativesCarbamic acid derivatives Q 0630 Synthesis, Antibacterial and Immunotropic Activity of Polyfluoroalkyl-N-arylcarbamates (III), (VI). -(STUDNEV, Y. N.; FROLOVSKII, V. A.; KRASNOV, A. P.; POZANTSEV, G. G.; STOLYAROV, V. P.; KINASH, O. F.; FOKIN, A. V.; Khim.-Farm.
Regularities of electrochemical carboxylation of carbon tetrachloride in conditions of galvanostatic diaphragmless electrolysis with a soluble zinc anode are studied. It is established that the generation of the anion at the cathode is accompanied by the discharge of salts of Zn 2+ , with the deposition of Zn 0 at the surface. The interaction between and ëé 2 in experimental conditions leads to the formation of zinc trichloromethylacetate, which proves to be very unstable in the dimethylformamide environment and undergoes fragmentation with the ëé 2 evolution. It is found that this process competes with currentless reduction of trichloromethylacetate under the action of Zn 0 deposited on the cathode surface. As a result, corresponding dichloromethylacetate with a small yield of ≤ 5.5% forms as the sole product of electrolysis.
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