Radical reaction of trinitromethane derivatives with cyclic ethers

1973 ◽  
Vol 22 (5) ◽  
pp. 1108-1110
Author(s):  
I. A. Leenson ◽  
G. B. Sergeev ◽  
O. P. Shitov ◽  
S. L. Ioffe ◽  
V. A. Tartakovskii
Keyword(s):  
Radical Reaction ◽  
Cyclic Ethers ◽  
Trinitromethane Derivatives

Dimethylzinc-initiated radical reaction of cyclic ethers with arylamines, alkoxyamines, and dialkylhydrazines

Tetrahedron ◽  
2005 ◽  
Vol 61 (2) ◽  
pp. 379-384 ◽  
Author(s):  
Yasutomo Yamamoto ◽  
Masaru Maekawa ◽  
Tito Akindele ◽  
Ken-ichi Yamada ◽  
Kiyoshi Tomioka
Keyword(s):  
Radical Reaction ◽  
Cyclic Ethers

New reaction of trinitromethane derivatives with cyclic ethers

1972 ◽  
Vol 21 (2) ◽  
pp. 447-447 ◽  
Author(s):  
O. P. Shitov ◽  
S. L. Ioffe ◽  
V. A. Tartakovskii ◽  
S. S. Novikov
Keyword(s):  
Cyclic Ethers ◽  
Trinitromethane Derivatives

Dimethylzinc-Initiated Radical Reaction of Cyclic Ethers with Arylamines, Alkoxyamines, and Dialkylhydrazines.

ChemInform ◽  
2005 ◽  
Vol 36 (21) ◽  
Author(s):  
Yasutomo Yamamoto ◽  
Masaru Maekawa ◽  
Tito Akindele ◽  
Ken-ichi Yamada ◽  
Kiyoshi Tomioka
Keyword(s):  
Radical Reaction ◽  
Cyclic Ethers

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

Participation of 19-substituents in electrophilic additions to 6,7-unsaturated 5α-cholestane and B-homo 5α-cholestane derivatives; A case of competition between the participation of an ambident neighboring group and external nucleophile attack

1980 ◽  
Vol 45 (2) ◽  
pp. 559-583 ◽  
Author(s):  
Pavel Kočovský ◽  
Ladislav Kohout ◽  
Václav Černý
Keyword(s):  
Perchloric Acid ◽  
Hydrobromic Acid ◽  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Neighboring Group ◽  
Acid Cleavage ◽  
Neighbouring Group Participation ◽  
Aqueous Perchloric Acid ◽  
The Difference ◽  
Electrophilic Additions

Hypobromous acid action upon the 6,7-unsaturated 19-substituted 5α-cholestans Va-Vc results in the formation of two types of products, the cyclic ethers IX as products of 5(O)n participation of the 19-substituent, and the bromohydrins X. All these compounds are formed from the 6α,7α-bromonium ions Va'-Vc'. Under the same conditions the B-homo-5α-cholestane derivatives VIIa-VIIc afforded solely the cyclic ethers XIV as products of 5(O)n participation of the 19-substituent in the cleavage of the bromonium ions VIIa'-VIIc'. Acid cleavage of the 6α,7α-epoxides VIb and VIc with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the cyclic ethers XI and the diols XII or bromohydrines XIII. The cyclic ethers XI arise by 5(O)n participation of the 19-substituent. The B-homo-6α, 7α-epoxide VIIIc on cleavage with aqueous perchloric acid have solely the cyclic ether XVc and by treatment with hydrobromic acid VIIIc afforded the mixture of XVc, as the main product, and of the bromohydrin XVIc. Discussed is the similarity of the bromonium ion cleavage with the fission of the corresponding epoxides, the mechanism of these reactions and the difference in the behaviour of the isomeric olefins Ia-c, IIIa-c, Va-c and VIIa-c and epoxides IIb,c, IVb,c, VIb,c and VIIIb,c. The competition between ambident neighbouring group participation and external nucleophile attack is discussed as well as the dependence of the products ratio on the nucleophilicity of the attacking species.

Boron insertion into alkyl ether bonds via zinc/nickel tandem catalysis

Science ◽  
2021 ◽  
Vol 372 (6538) ◽  
pp. 175-182
Author(s):  
Hairong Lyu ◽  
Ilia Kevlishvili ◽  
Xuan Yu ◽  
Peng Liu ◽  
Guangbin Dong
Keyword(s):  
Nickel Catalyst ◽  
Bioactive Compounds ◽  
Cyclic Ethers ◽  
Alkyl Ether ◽  
Tandem Catalysis ◽  
Mechanistic Studies ◽  
Alkyl Ethers ◽  
Nitrogen Substitution ◽  
Zinc Nickel

Mild methods to cleave the carbon-oxygen (C−O) bond in alkyl ethers could simplify chemical syntheses through the elaboration of these robust, readily available precursors. Here we report that dibromoboranes react with alkyl ethers in the presence of a nickel catalyst and zinc reductant to insert boron into the C−O bond. Subsequent reactivity can effect oxygen-to-nitrogen substitution or one-carbon homologation of cyclic ethers and more broadly streamline preparation of bioactive compounds. Mechanistic studies reveal a cleavage-then-rebound pathway via zinc/nickel tandem catalysis.

Crystal Violet, an Electronic Model Substance for Rubber and Related Olefins

1951 ◽  
Vol 24 (1) ◽  
pp. 169-181 ◽  
Author(s):  
G. J. van Veersen
Keyword(s):  
Crystal Violet ◽  
Electronic Structures ◽  
Radical Reaction ◽  
Test Tube ◽  
Chemical Agent ◽  
Blue Color ◽  
Electronic Model ◽  
Model Substance ◽  
Model Substances ◽  
Polar Reaction

Abstract It is shown that triphenylmethyl dyes like crystal violet can be used as model substances for rubber and related olefins. Arguments are given in support of the assumption that agents which react with rubber and related olefins in a polar manner cause a reversible shift in color from blue to yellow with crystal violet, whereas a fading of the blue color of crystal violet (if alkaline or reducing agents are excluded) points to a radical reaction. Since the electronic structures of donor olefins and crystal violet are considered and not the molecular structure, as usually is done in the choice of a model substance, these dyes have been named electronic model substances. Though crystal violet, as an electronic model substance cannot be used for the study of the overall reactions, information can often be obtained concerning the first step in a reaction of rubber with a certain chemical agent by means of a simple test-tube reaction with crystal violet. It was pointed out that the π-electron availability at the non-methylated carbon atom of the double bond in rubber and at the nitrogen atoms in crystal violet is probably of the same order. As an application of crystal violet as an electronic model substance for rubber, a polar reaction between sulfur and rubber is suggested as the first step in vulcanization.

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