Showing papers by "Yu. N. Ogibin published in 1981"
TL;DR: In this article, the oxidation of cyanohydrins by peroxydisulfate in the absence of Ag+ ion proceeds via the cleavage of H atoms from the hydrocarbon groupings of the cyanohydrin by the sulfate ion-radicals.
Abstract: 1.
The oxidation of cyanohydrins by the S2O82−-Ag+ system begins with the reaction of the OH group of the cyanohydrin with silver ions, which results in the formation of 1-cyanoalkoxyl radicals. The sulfate ion-radicals practically do not take part in the direct oxidation of cyanohydrins.
2.
The initiation of the oxidation of cyanohydrins by peroxydisulfate in the absence of Ag+ ion proceeds via the cleavage of H atoms from the hydrocarbon groupings of the cyanohydrin by the sulfate ion-radicals. The 4(5)-hydroxy-4(5)-cyanoalkyl radicals, formed as a result of the 1, 4- and 1, 5-migration of the cyano group and subsequent oxidation, are converted to 5- and 6-cyanoalkanones. The oxidative rearrangement of alkanone cyanohydrins to 6-cyanoalkanones was observed for the first time.
1 citations
TL;DR: The selectivity of the oxidative decarboxylation of acids with carboxyl groups at secondary and tertiary C atoms under the action of the S2O82−--Ag+ and S 2O82 −-Ag +- Cu2+ systems is at least an order of magnitude faster than that of acids having COOH groups at a primary C atom, as a result of which 3 and 4-carboxyalkyl radicals with the general formula R'RĊ(CH2)nCOOH (R is alkyl or
Abstract: 1.
The oxidative decarboxylation of acids with carboxyl groups at secondary and tertiary C atoms under the action of the S2O82−- Ag+ and S2O82−-Ag+- Cu2+ systems is at least an order of magnitude faster than that of acids with COOH groups at a primary C atom, as a result of which 3- and 4-carboxyalkyl radicals with the general formula R'RĊ(CH2)nCOOH (R is alkyl or phenyl, R′ is H or alkyl, n=2 or 3) are generated with > 90% selectivity from 2-substituted glutaric and adipic acids.
2.
The 3- and 4-carboxyalkyl radicals are completely or partially converted under their generation conditions into lactones. The selectivity of the oxidative lactonization increases from 0.30 to 0.97 along the series of radicals C2H5ĊH(CH2)3COOH, C2H5ĊH(CH2)2COOH, ĊH2(CH2)3COOH, ĊH2(CH2)2COOH, (CH3)2Ċ(CH2)2-COOH, and C2H5ĊH(CH2)2COOH in the case of the S2O82−-Ag+ system and from 0.72 to 1 along this series in the case of the S2O82−- Ag+- Cu2+ system.
1 citations
TL;DR: In this article, a new method was developed for the synthesis of the nitriles of 5-ketoalkanoic acids, and the synthesis was carried out in the presence of 2-nonanone and 2-pentanone.
Abstract: 1.
Alkanone cyanohydrins of general formula R(CH2)3CR'(OH)CN (R=H or alkyl, R' =alkyl) are efficiently oxidized by the system S2O82--Ag+ to 1-cyanoalkoxyl radicals, which then undergo a highly selective rearrangement, with successive migration of the H atom and CN group and oxidation to δ-ketonitriles RCH(CN)CH2CH2COR'.
2.
The cyanohydrins of 2-pentanone (Ia), 2-hexanone (Ib), 2-octanone (Ic), and 2-nonanone (Id) are oxidized by the system S2O82--Ag+ ∿4-18 times faster than tert-butanol, and in their oxidative ability they fall into the sequence: (Id) > (Ic) > (Ib) > (Ia).
3.
A new method was developed for the synthesis of the nitriles of 5-ketoalkanoic acids.
TL;DR: The action of the S2O82−-Ag+ system on the cyanohydrins of cyclopentanone and 2-methylcyclopentanones leads to isomerization with opening of the cyclopedentane ring and 1,5migration of the cyano group and the formation of 5-cyano-substituted pentanoic and hexanoic acids as mentioned in this paper.
Abstract: 1.
The action of the S2O82−-Ag+ system on the cyanohydrins of cyclopentanone and 2-methylcyclopentanone leads to isomerization with opening of the cyclopentane ring and 1,5-migration of the cyano group and the formation of 5-cyano-substituted pentanoic and hexanoic acids.
2.
2-Methylcyclohexanone cyanohydrin under analogous conditions isomerizes with 1,6-migration of the cyano group to give 6-cyanoheptanoic acid, while cycloheptanone cyanohydrin undergoes 1,4-migration of the cyano group without ring opening to give 4-cyanocycloheptanone.
3.
Cyelopentanone and cycloheptanone cyanohydrins are oxidized ∼1.7 times more rapidly by the S2O82−-Ag+ system at 60°C than cyclohexanone cyanohydrin. The cyanohydrins of 2-methyl-substituted cycloalkanones are oxidized about twice as rapidly as their unsubstituted analogs.
TL;DR: In this paper, the first stage of the reaction to 1-hydroxy-1-cyanoalkyl and 1-cyclohexyl radicals was shown to be competitive with the second stage.
Abstract: 1.
Alkanal cyanohydrins (ACH) of general formula R(CH2)3CH(OH)CN are oxidized by the system S2O82−Ag+ to the acids R(CH2)3COOH and NCCHRCH2CH2COOH, indicating the competitive conversion of the ACH in the initial stage of the reaction to 1-hydroxy-1-cyanoalkyl and 1-cyanoalkoxyl radicals.
2.
The oxidation of acetaldehyde cyanohydrin at 60° proceeds at approximately twice the rate of the oxidation of butanal, pentanal, isopentanal, and heptanal cyanohydrins, and approximately ten times as fast as that of tert-butanol.
TL;DR: A new C-C bond on homolytic addition of dimethyl esters of succinic, glutaric, and adipic acids to the dimethyl or diethyl ester of citraconic, itaconic and acetylenedicarboxylic acids is formed between the α-C atom of the acyl part of the ester as mentioned in this paper.
Abstract: 1.
A new C-C bond on homolytic addition of dimethyl esters of succinic, glutaric, and adipic acids to the dimethyl or diethyl ester of citraconic, itaconic, and acetylenedicarboxylic acids is formed between theα-C atom of the acyl part of the ester of the alkanedicarboxylic acid and the least substituted C atom of the C=C bond of the ester of the unsaturated acid.
2.
As an acceptor of radicals generated from esters of alkanedicarboxylic acids, the ester of citraconic acid is substantially less effective than the esters of maleic, itaconic, and acetylenedicarboxylic acids. The latter are close to one another in capability of forming addition products with esters of succinic, glutaric, and adipic acids.
3.
The principal products of homolytic reaction of dimethyl esters of glutaric and adipic acids with the dimethyl ester of acetylenedicarboxylic acid are respectively the tetramethyl esters of 2-pentene-1,2,3,5-tetracarboxylic acid and 2-hexene-1,2,3,6-tetracarboxylic acid.