Showing papers by "G. I. Nikishin published in 1989"
TL;DR: In the Na2S2O8-NaCN system, the corresponding 4-cyano(methyl)cyclohexanones are formed regiospecifically.
Abstract: 1.
During the oxidative cyanation of 2-, 3-, and 4-methylcyclohexanones in the Na2S2O8-NaCN system the corresponding 4-cyano(methyl)cyclohexanones are formed regiospecifically.
2.
The oxidative cyanation of 2- and 3-methylcyclohexanones takes place diastereoselectively with the formation of trans- and cis-4-cyano-2(3)-methylcyclohexanones in a ratio of 1.5∶1 (or 2∶1). The selectivity of cyanation is determined by the bridge structure of the intermediate 4-oxo(methyl)cyclohexyl radicals, which are the precursors of the 4-cyanocyclohexanones.
3 citations
TL;DR: In this paper, a single stage remote oxidation of ketones to γ- and δ-diketones has been carried out in a sodium peroxysulfate-iron(II) sulfate system.
Abstract: A single stage remote oxidation of ketones to γ- and δ-diketones has been carried out in a sodium peroxysulfate-iron(II) sulfate system.
2 citations
TL;DR: In the presence of (PPh3)2Co(Ph2PCH 2CH2CH2PPh2) gives four-membered and fivemembered cycloalkanones as discussed by the authors.
Abstract: Catalytic cyclization of γ,σ-unsaturated aldehydes (intramolecular hydroacylation) in the presence of (PPh3)2Co(Ph2PCH2CH2PPh2) gives four-membered and five-membered cycloalkanones. Depending on aldehyde structure the selectivity is 90–97% at 10–100% aldehyde conversion.
2 citations
TL;DR: In this article, an electrochemical oxidation of malonic esters in methanol, ethanol, or acetonitrile in the presence of alkali metal bromides as catalyst-carriers is described.
Abstract: The electrochemical oxidation of malonic esters in methanol, ethanol, or acetonitrile in the presence of alkali metal bromides as catalyst-carriers, with the use of 1.8–2 F of electricity per mole of the starting malonic ester leads to esters of propane-1,1,2,2,3,3-hexacarboxylic acid in a yield of up to 90%.
1 citations
TL;DR: In this article, a synthetic method of preparing 5-bromopentanoic acid was developede by oxidation of cyclopentanone with aqueous solutions of H2O2.
Abstract: A synthetic method of preparing 5-bromopentanoic acid was develope by oxidation of cyclopentanone with aqueous solutions of H2O2. Subsequent decomposition of the resulting hydroperoxide of cyclopentanone was accomplished with a catalytic quantity of copper salt in the presence of alkali bromides.
1 citations
TL;DR: According to 1H and 31P NMR spectra, the cationic complexes [Rh(PMe3)4]X (X=Cl, BPh4) exist in solution (H2O, MeOH, MeCN) as fluxional five-coordinate species as mentioned in this paper.
Abstract: 1.
According to1H and31P NMR spectra, the cationic complexes [Rh(PMe3)4]X (X=Cl, BPh4) exist in solution (H2O, MeOH, MeCN) as fluxional five-coordinate species [Rh(PMe3)4. (solvent)]X.
2.
The synthesized complexes [Rh(PMe3)4O2]Cl and [Rh(PMe3)4O2]BPh4 have trigonal bipyramidal structure in solution according to31P and1H NMR spectroscopy.
TL;DR: In this paper, spin traps have been used to identify the alkoxyl and secondary C-centered radicals generated in the oxidation of an alcohol with Pb (OAc)4 and with the system Pb(OAc 4-LiCl.
Abstract: 1.
In the oxidation of primary, secondary, and tertiary aliphatic alcohols with the system Pb(OAc)4-metal chloride, the principal product is the δ-chloroalkanol.
2.
EPR using spin traps has been used to identify the alkoxyl and secondary C-centered radicals generated in the oxidation.of an alcohol with Pb (OAc)4 and with the system Pb(OAc)4-LiCl.
TL;DR: In this paper, the inhibitor method using tetranitromethane was used to demonstrate a radical pathway in the oxidation of carbonyl compounds by organic hydroperoxides or hydrogen peroxide in water at 25°C.
Abstract: The inhibitor method using tetranitromethane was used to demonstrate a radical pathway in the oxidation of carbonyl compounds by organic hydroperoxides or hydrogen peroxide in water at 25°C. The initial radical formation rate was studied relative to the concentration and nature of the components and pH of the medium.
TL;DR: In this paper, a selective method was developed for the synthesis of α-methylene-1,5-diketones by dimerization of vinyl ketones catalyzed by RhCl(PMe3)3.
Abstract: A selective method has been developed for the synthesis of α-methylene-1,5-diketones by dimerization of vinyl ketones catalyzed by RhCl(PMe3)3. Aromatic vinyl ketones dimerize more readily than aliphatic vinyl ketones.
TL;DR: In this paper, a method for synthesis of 2-alkyl-5-aryl and 2,5-diaryl-1,3,4-thiadiazoles by successive reaction of thioamides with tert-butyl hypochlorite and benzothiohydrazides was developed.
Abstract: A method for synthesis of 2-alkyl-5-aryl- and 2,5-diaryl-1,3,4-thiadiazoles by successive reaction of thioamides with tert-butyl hypochlorite and benzothiohydrazides was developed. The first step in the formation of 1,3,4-thiadiazoles consists of oxidation of thioamides with tert-butyl hypochlorite with O atom transfer to the S atom, which was established by transformation of N-methyl-thiobutanamide into N-(methylimino)butanesulfenic acid.
TL;DR: In this article, it was shown that 3-Alkenethiols are readily cyclized upon thermal or homolytic initiation with the formation of the corresponding tetrahydrothiophenes (thiolanes).
Abstract: 3-Alkenethiols are readily cyclized upon thermal or homolytic initiation with the formation of the corresponding tetrahydrothiophenes (thiolanes) [1,2]o We have found that this reaction may serve as an efficient method for the synthesis of bicyclic thiolanes (IV) and previously unreported spirothiolanes (II). Homoallyl mercaptans (I) obtained by the alkylborylation of thioketones [3] in the presence of the Pr3B-O2-CH3OH system used to generate thiyl radicals from mercaptans [4,5] cyclize to give spirothiolanes (II). The experimental procedure was analogous to that given in our previous work [5].