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1.
G. A. Abakumov V. K. Cherkasov T. N. Kocherova N. O. Druzhkov Yu. A. Kurskii L. G. Abakumova 《Russian Chemical Bulletin》2006,55(7):1195-1199
Reactions of 3,6-di(tert-butyl)-o-benzoquinone with primary amines occur by the nucleophilic 1,4-addition mechanism and lead to the corresponding 2-hydroxy-p-quinonimines, which exist in solutions in equilibrium with tautomeric 4-amino-o-quinones. The thermodynamic parameters of this prototropic isomerism were determined by NMR spectroscopy. In the case of
a secondary amine (piperidine), a derivative of 4-amino-o-quinone was obtained; the corresponding o-semiquinone complexes were studied in solution by ESR spectroscopy.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1151–1155, July, 2006. 相似文献
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G. A. Abakumov V. I. Nevodchikov N. O. Druzhkov L. N. Zakharov L. G. Abakumova Yu. A. Kurskii V. K. Cherkasov 《Russian Chemical Bulletin》1997,46(4):771-776
New di-o-quinones of the biphenyl series, namely, 2,2′-dialkyl-5,5′-di-tert-butylbiphenyl-3,4,3′,4′-diquinones, were synthesized. Their structures were established by IR and NMR spectroscopy. The molecular
structure of 2,2′-dimethyl-5,5′-di-tert-butylbiphenyl-3,4,3′,4′-diquinone was established by X-ray structural analysis. The structure is characterized by orthogonal
(the torsion angle is 82.9°) mutual arrangement ofo-benzoquinone fragments. ESR studies demonstrated that chemical reduction of diquinone proceeds in four oneelectron stages
to form paramagnetic mono- and trianions as intermediates. Quinopyrocatechols, which are intermediates in the synthesis of
di-o-quinones, were isolated and characterized.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 804–809, April, 1997. 相似文献
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M.P. Shurygina Yu.A. Kurskii N.O. Druzhkov S.A. Chesnokov L.G. Abakumova G.K. Fukin G.A. Abakumov 《Tetrahedron》2008,64(41):9784-9788
It was established that photodecarbonylation of o-benzoquinones occurs by irradiation not only by UV-light, but visible light (λ>520 nm) too. Study of the series of 4,5-di-substituted 3,6-di-tert-butyl-o-benzoquinones detected that the only product of photoreaction is the corresponding 3,4-di-substituted 2,5-di-tert-butyl-cyclopentadienone, which is formed in a yield close to quantitative. NMR monitoring of reaction of photodecarbonylation of o-benzoquinones detected that this is a two-stage process. In the first stage the photoexcited molecule of quinone rearranges into bicyclo compound (bicyclo[1.3.0]hexa-3-en-2,6-dione) containing five- and three- membered cycles, which spontaneously decomposes during the following dark stage into cyclopentadienone and a molecule of CO. 相似文献
5.
N. K. Abakumova 《Acoustical Physics》2008,54(4):481-485
Results of an experimental study of shallow-water sound fields are presented. The experiment is carried out in the frequency range 112–3200 Hz on a 150-km-long propagation track. A comparative analysis of experimental and calculated data is performed. Estimates are obtained for the loss coefficient associated with sound attenuation in the bottom, as well as for the parameters of the bottom, which is modeled as a homogeneous liquid absorbing half-space. The vertical interference structure of the sound field formed at a frequency of 112 Hz in the vicinity of the source is considered. 相似文献
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G. A. Abakumov N. O. Druzhkov Yu. A. Kurskii L. G. Abakumova A. S. Shavyrin G. K. Fukin A. I. Poddel’skii V. K. Cherkasov L. S. Okhlopkova 《Russian Chemical Bulletin》2005,54(11):2571-2577
Cyclization of substituted quinone imines and diazabutadiene derivatives of aminophenols affords 4aH-phenoxazine or 4H-1,4-benzoxazine derivatives, which are finally transformed into the following fused heterocycles: the stable 1,4,6,8-tetra(tert-butyl)phenoxazin-10-yl radical and 7a,14a,15a, 15b-tetrahydro-14,16-dioxa-5,9-diaza-8,15-ethenohexaphene and 5a,6,11a, 12-tetrahydro[1,4]benzoxazino[3,2-b][1,4]benzoxazine derivatives. The influence of the substituents on the pathways of the reactions of intermediate benzoxazines
and phenoxazines, such as oxidation, [2+4] dimerization, and the closure of the second ring, was studied. The structures of
the fused heterocycles were determined by X-ray diffraction, NMR spectroscopy, and ESR.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2491–2496, November, 2005. 相似文献
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