Competitive conversions of carbonyl-containing methanofullerenes induced by electron transfer

The electrochemical reduction of carbonyl-containing methanofullerenes is studied by methods of cyclic voltammetry and ESR with in situ electrolysis in the environment of 0.1 M Bu₄NBF₄ in o-dichlorobenzene-dimethylformamide (3:1 by volume). It is shown that the one-electron transfer onto the fullerene sphere of these compounds induces opening of the three-membered cycle, which leads to processes of retrocyclopropanation, transfer of the adduct onto the fullerene sphere of another molecule with the formation of bismethanofullerenes, and transformation into fullerodihydrofuran. The totality of competitive processes and the balance between these is defined by the nature of substituents at the exocarbon atom and the experimental conditions. The opening process is interpreted as the intramolecular electron transfer from the fullerene sphere onto the three-membered cycle.     

Synthesis of esters of oxathiinecarboxylic and dithiinecarboxylic acids and their derivatives

Conclusions The reaction of the methyl ester of 3-phenyl-3-chloro-2-ketopropionic acid with mercaptoethanol and 1,2-dithioglycol gives derivatives of oxathiine and dithiine. The oxidation of these products gives the corresponding sulfones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1670–1672, July, 1988.     

Fulleropyrrolidine-containing sterically hindered phenol. Synthesis,structure, and properties

Fulleropyrrolidine containing a sterically hindered phenolic fragment was synthesized by the reaction of fullerene C₆₀ with N-methylglycine and 3,5-di-tert-butyl-4-hydroxybenzaldehyde. Electrochemical reduction of fulleropyrrolidine-containing phenol 1 and the corresponding phenoxide ion proceeded stepwise to form stable radical anions, dianions, and trianions. The radical anion (g = 2.0000) and the phenoxyl radical (g = 2.0045) obtained by chemical oxidation with lead dioxide were identified by ESR spectroscopy. The electron affinity of fulleropyrrolidine was estimated at 2.58 eV. For the phenoxide ion, the electrochemical gap was determined (E = E _I ^ox – E _I ^red = 0.47 V). The heats of formation and the energies of the frontier orbitals of fulleropyrrolidine and its transformation products were evaluated by the PM3 method.     

Dichloromethyl tert-butyl ketone in the Darzens reaction

The condensation of dichloromethyl tert-butyl ketone (1) with benzaldehyde, para-bromobenzaldehyde, and 2,4-dichlorobenzaldehyde under conditions for the Darzens reaction gives 1-aryl-1-chloro-4,4-dimethyl-2,3-pentanediones (2–4). In the case of nitrobenzaldehydes, the reaction products are 1-aryl-2-chloro-1,2-epoxy-4,4-dimethylpentanones (5 and 6), which isomerize to -chloroketones (7 and 8) upon prolonged storage or heating at reflux in benzene.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 438–441, February, 1992.     

Electrochemical reduction and oxidation of fullerenopyrrolidines and the ESR spectra of paramagnetic intermediates

Electroreduction and electrooxidation of monosubstituted N-methyl[60]fullerenopyrrolidines were studied by cyclic voltammetry and potentiostatic microelectrolysis in the cavity of an ESR spectrometer. Stepwise reversible transfer of three electrons to the fullerenopyrrolidine molecule results in the formation of stable radical anions (according to ESR, g = 2.0000, H = 0.8 G), dianions, and radical trianions (according to ESR, g = 2.0015, H = 1.5 G). The reduction potentials vary over narrow limits depending on the nature of the substituents in the pyrrolidine fragment of the compounds. Electrooxidation is irreversible and occurs in either one or two steps. For compounds containing the aniline, indole, or phenol fragment, the first step is associated with oxidation of these fragments and only after that, is the fullerenopyrrolidine core oxidized. Oxidation of the pyrrolidine fragment is substantially more difficult than that of tertiary amines.     

Alkylselenophosphonium salts

Conclusions Methylselenophosphonium salts have been obtained for the first time by the reaction of full amides of phosphoroselenoic and alkylphosphonoselenoic acids with methyl iodide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, p. 169, January, 1969.     

Darzens synthesis of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid derivatives

Esters and amides of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid were prepared by the reaction of furfural with dichloroacetic acid derivatives under the conditions of the Darzens condensation. The structures of the reaction products were confirmed by their¹H NMR and IR spectra and chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1444–1448, August, 1994.     

Synthesis and properties of new fullerene C60 derivatives,containing acetonide and polyol fragments

New mono- and hexa-methanofullerenes containing different number of acetonide groups are synthesized and characterized. Removing the acetonide protection leads to new chromatographically pure water-soluble polyol methanofullerenes with essentially quantitative yields.