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N. D. Pokhilo M. I. Kiseleva V. V. Makhan’kov V. Ph. Anufriev 《Chemistry of Natural Compounds》2008,44(3):287-291
The cytotoxic activity of the principal intermediates and side products of echinochrome synthesis toward gametes of the sea
urchin Strogylocentrotus intermedius was studied. Di-and trichloro naphthazarin derivatives with two vicinal Cl atoms were the most active.
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Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 228–231, May–June, 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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