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G. V. Malinovskaya A. Ya. Chizhova V. Ph. Anufriev V. P. Glazunov V. A. Denisenko 《Russian Chemical Bulletin》1999,48(8):1587-1589
Based on IR and1H and13C NMR spectroscopic studies, the oxidation product of echinochrome with Ag2O was assigned the structure of 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone.
For part 4, see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1607–1609, August, 1999. 相似文献
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I. Yu. Bakunina E. A. Kol′tsova N. D. Pokhilo O. P. Shestak A. Ya. Yakubovskaya T. N. Zvyagintseva V. F. Anufriev 《Chemistry of Natural Compounds》2009,45(1):69-73
The effect of natural and synthetic polyhydroxy-1,4-naphthoquinones on the hydrolytic activity of α-galactosidase from marine bacteria was studied. It was shown that the inhibiting properties relative to the enzyme depended
on the nature of the substituents, their number, and their position in the structure of these compounds.
Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–63, January–February, 2009. 相似文献
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D. N. Pelageev M. N. Panchenko N. D. Pokhilo V. A. Denisenko V. F. Anufriev 《Chemistry of Natural Compounds》2008,44(6):719-723
5,8-Dihydroxy-2,3,6-trimethoxy-7-ethyl-1,4-naphthoquinone (1) was used to synthesize in high yield 5,8-dihydroxy-7(1′-hydroxyethyl)-2,3,6-trimethoxy-1,4-naphthoquinone (lomazarin, 3), a pigment from Lomandra hastilis. Alkaline hydrolysis of lomazarin produced mainly 5,6,8-trihydroxy-2,3-dimethoxy-1,4-naphthoquinone (9) through a retro-aldol decomposition of the 6-keto-form of 5,6,8-trihydroxy-7(1′-hydroxyethyl)-2,3-dimethoxy-1,4-naphthoquinone
(13b) formed during the reaction. 2,5,8-Trihydroxy-7(1′-hydroxyethyl)-3,6-dimethoxy-1,4-naphthoquinone (norlomazarin, 4a), a pigment of L. hastilis, and its 3,5,8-trihydroxy-7(1′-hydroxyethyl)-2,6-dimethoxy isomer 4b were formed as a difficultly separable mixture in addition to quinone 9.
Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 581–584, November–December, 2008. 相似文献
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The molecular geometry and electronic structure of hydroxy-substituted naphthazarin (NZ)-7-ethyl-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone
(echinochrome A, (Et)NZ(β-OH)3, 1) were calculated by the B3LYP/6-311G(d) method. The influence of the (i) character of the β-OH groups dissociation and (ii)
conformational mobility of molecule 1 and the anions, radicals, and radical anions derived from 1 on the energy of their reactions with hydroperoxyl radical was studied by the (U)B3LYP/6-31G and (U)B3LYP/6-311G(d) methods.
The enol-enolic tautomerism due to the transfer of hydrogen atoms of α-OH groups and rotational isomerism of the β-OH groups
at the C(2) and C(3) atoms and of the α-OH groups at the C(5) and C(8) atoms were studied. The equilibrium in the gas-phase
reaction 1 + •OOH ⇄ (Et)(HO-β)2NZ(β-O•) + HOOH (1) (quenching of hydroperoxyl radical) is shifted to the separated reagents. Heterolysis of the O—H bond in one
of the three β-hydroxy groups considerably reduces the energy of subsequent O—H bond homolysis in either of the two remaining
β-hydroxy groups. As a consequence, the reaction (Et)(HO-β)2NZ(β-O−) + •OOH ⇄ (Et)(HO-β,−O-β)NZ(β-O•) + HOOH (2) (quenching of hydroperoxyl radical) becomes exothermic and the equilibrium is shifted to the formation of hydrogen
peroxide. The Gibbs energy gain in reaction (2) varies from −6.4 to −10.9 kcal mol−1 depending on which β-hydroxy group is involved in the O—H bond homolysis.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 400–415, March, 2007. 相似文献
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