Effect of External Factors on the Ferromagnetic Resonance Line Width in Exchange-Biased Structures

Physics of the Solid State - The external factors which influence the ferromagnetic resonance (FMR) line width in bilayer (ferromagnet/antiferromagnet) exchange-biased systems are studied. The...     

Extensions with Archimedean ramification points

A subgroup of the Galois group of an extension of an algebraic number field that is closed with respect to 2-extensions is considered. This subgroup is generated by the inertia sub-groups of the real points of the maximal real subfield. It is proved that this group is the free product of the Cantor set of cyclic groups of order 2 in the category of pro-2-groups.Translated from Matematicheskie Zametki, Vol. 14, No. 1, pp. 61–66, July, 1973.The author would like to thank L. V. Kuz'min for his guidance in this paper and E. S. Golod for his improving comments.     

Some Heterocyclization Reactions of N,N'-Dimethoxycarbonyl-o-benzoquinone Diimine

Russian Journal of Organic Chemistry -     

Sigmatropic rearrangements of alkenyl benzofuryl and benzothienyl sulfides

The thio Claisen rearrangement of 2-butenyl 2-benzofuryl sulfide, cyclopenten-2-yl 2-benzofuryl sulfide, 2-butenyl 2-benzothienyl sulfide, and cyclopenten-2-yl 2-benzothienyl sulfide was investigated. The rates, energies and entropies of activation of the process were calculated, and the effect of the structure of the sulfide, the polarity of the solvent, and the temperature was demonstrated by comparison of these values. The 1,3-thioallyl rearrangement of 1-methylallyl 3-methyl-2-benzothienyl sulfide was studied, and it was shown that this reaction competes with the thio Claisen rearrangement.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1338–1341, October, 1982.     

Electronic absorption spectra and acidities of heteroaromatic thiols

The electronic absorption spectra of a number of substituted and unsubstituted thiophene-, benzothiophene-, and benzofuranthiols were studied, and their ionization constants were determined by establishment of the dependence of the optical densities of aqueous alcohol solutions of them on the pH.Translated from Khimiya Getero-tsiklicheskikh Soedinenii, No. 10, pp. 1313–1314, October, 1980.     

[3,3]-sigmatropic rearrangement of allyl 2-benzothienyl sulfide

Allyl 2-benzothienyl sulfide at 20–120 °C undergoes a [3,3]-sigmatropic rearrangement to give 3-allylbenzothiophene-2-thiol. The kinetic parameters of the reaction were studied. Under the experimental conditions the thiol undergoes cyclization to give 2-methyl-2,3-dihydrobenzothieno[2,3-b]thiophene, 2-methyl-benzothieno[2,3-b]thiophene, and benzothieno[2,3-b]dihydrothiopyran. Allyl 3-methyl-2-benzothienyl sulfide does not form a thiol even at 150–190 °C but rather forms only bis(3-methyl-2-benzothienyl) disulfide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 615–618, May, 1981.     

Reactions of heteroaromatic thiols with 1,3-butadiene and cyclopentadiene

The formation of 1,2 and 1,4 adducts in the reaction of 5-chloro-2-thiophenethiol, 2-benzofuranthiol, 2-benzothiophenethiol, and 3-methyl-2-benzothiophenethiol with conjugated dienes in the presence of various amounts of ethylsulfuric acid and also without a catalyst was studied. Catalytic acceleration of the reaction with ethylsulfuric acid indicates the heterolytic character of the addition.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1335–1337, October, 1982.