- Antipsoriatic Anthrones with Modulated Redox Properties. 1. Novel 10-Substituted 1,8-Dihydroxy-9(10H)-anthracenones as Inhibitors of 5-Lipoxygenase
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The syntheses, the biological evaluation, and the structure-activity relationships of a novel series of 1,8-dihydroxy-9(10H)-anthracenones bearing acyl-, alkyl-, or alkylidene-linked aromatic substituents in the 10-position are described.The phenylacyl and phenylalkylidene analogs were far more potent inhibitors of 5-lipoxygenase (5-LO) from bovine polymorphonuclear leukocytes (IC50 values in the 10-7 M range) than the antipsoriatic drug anthralin, whereas phenylalkyl analogs were only weak inhibitors.Among the active compounds were both potent generators of hydroxyl radicals, as determined by deoxyribose degradation, and strong reducers of the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH).However, several derivatives of this series maintained 5-LO inhibitory activity but did not generate hydroxyl radicals and were not reactive with DPPH.In particular, phenylacyl analogs were also 6 times more efficient in inhibition of lipid peroxidation in model membranes than anthralin.Structure-activity relationships have shown that the presence of free phenolic groups in the attached aromatic ring is beneficial but not required for 5-LO inhibitory potency.The inhibitory potency in the 10-phenylacyl series increased with the length of the acyl chain with three methylene units being the optimum, suggesting a specific enzyme interaction which would not be expected for nonspecific redox inhibitors.
- Mueller, Klaus,Guerster, Dieter,Piwek, Susanne,Wiegrebe, Wolfgang
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p. 4099 - 4107
(2007/10/02)
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- 2-Azaallenium Salts from N-Benzylidene-α-methoxybenzylamines
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New phenyl-substituted 2-azaallenium salts 1 with variable substitution pattern were synthesized in high yields and under mild reaction conditions by treatment of N-benzylidene-α-methoxy-benzylamines 4 with acylium salts.The amines 4 are easily accessible from imines 2 and α-chloro ethers 3 or from 2,4-diaza-1,4-pentadiones 7; only in the case of strong steric hindrance an alternate reaction (forming imidazole 6) takes place.Some of the new 2-azaallenium salts (1ea-1ed, 1fa-1fd) show high tendency for intramolecular cyclisation reactions leading to isoquinoline derivatives 8 and 9. - The structures of the salts 1 in solution were analysed on the basis of 1H- and 13C-NMR spectra with respect to the dynamic behaviour of the cations.For 1aa-1j cumulene structures were derived, for the intensively coloured 1k, however, a 2-azaallyl cation structure of the aza-trimethine dyestuff type was found (IR data). - Keywords: 2-Azaallenium Salts; N-Benzylidene-α-methoxybenzylamines
- Weidner, Reinhold,Wuerthwein, Ernst-Ulrich
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p. 1095 - 1106
(2007/10/02)
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