New long-wavelength perylenequinones. The reaction between hypocrellin B and mercapto compounds

Certain new mercapto-substituted hypocrellin B (HB) derivatives have been synthesized and characterized. The possible mechanism for this reaction, and the properties of the resulting compound, are discussed. Interaction of HB with mercapto compounds in dimethyl sulfoxide containing ammonium hydroxid...

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Bibliographic Details
Published in:Dyes and pigments 1997-12, Vol.35 (4), p.297-310
Main Authors: WENG, M, ZHANG, M.-H, MA, L, SHEN, T, JIANG, L.-J
Format: Article
Language:English
Subjects:
Chemistry
ESR
Exact sciences and technology
free radical and nucleophilic addition
Free radicals chemistry
hypocrellin B
mercapto compounds
Organic chemistry
reaction mechanism
Reactivity and mechanisms
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Summary:Certain new mercapto-substituted hypocrellin B (HB) derivatives have been synthesized and characterized. The possible mechanism for this reaction, and the properties of the resulting compound, are discussed. Interaction of HB with mercapto compounds in dimethyl sulfoxide containing ammonium hydroxide proceeded very quickly, and the mono- or di-substituted HB derivatives were formed. Their significantly enhanced red absorptivities and strong 1O 2-generating functions may qualify them as promising PDT agents. In addition, the semiquinone radical anion of HB (HB −.) was one of the reaction intermediates detected by ESR and Uv-vis spectrum. Moreover, the effect of free radical quenchers on this reaction have also been investigated. On the basis of the experimental evidence, the mechanism of free radical addition and nucleophilic addition are proposed.
ISSN:0143-7208
1873-3743
DOI:10.1016/S0143-7208(97)00122-8