- A pentacene intermediate via formal intramolecular photoredox of a 6, 13-pentacenequinone in aqueous solution
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The formal intramolecular photoredox reaction (or tandem phototautomerizations) of aromatic ketones in aqueous solution discovered in our laboratory has been extended to a number of acenequinones. In particular, we were interested in whether the photoredox reaction could be applied to 2-(hydroxymethyl)-6,13-pentacenequinone (4), which would result in 2-formyl-6,13-dihydroxypentacene (10) and hence offer a photochemical method for synthesizing a pentacene derivative. Whereas a number of acenequinones displayed a range of photoredox reactivity, photolysis of 4 in acidic aqueous solution (pH 3) resulted in a clean intramolecular photoredox reaction, via an enol intermediate, to give 10 (green compound; Φ ~ 0.2 at pH 1), which was too reactive for isolation or trapping by standard ArOH trapping agents such as acetic anhydride. These reactions may be viewed as a one-way photochemical intramolecular "redox switch" from, quinone to hydroquinone with concurrent oxidation of an attached hydroxymethyl (alcohol) moiety. Without the attached alcohol moiety, these acenequinones are photostable in aqueous solution. The trend in observed relative reactivity may be partially rationalized by examining changes in molecular orbital coefficients observed in the calculated HOMOs and LUMOs (at the AM1 level).
- Hou, Yunyan,Wan, Peter
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- 6-Substituted 1,4-naphthoquinone oxime derivatives (I): synthesis and evaluation of their cytotoxic activity
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Abstract: A series of 6-substituted 1,4-naphthoquinone oxime derivatives were synthesized and evaluated for their in vitro cytotoxicity against four cancer cell lines and one normal cell line. Some compounds exhibited moderate to good cytotoxicity towards cancer cells and meanwhile all the synthesized compounds displayed no apparent cytotoxic activity against normal cells (IC50?>?100?μM). Among these oxime derivatives, three compounds showed more potent cytotoxicity against human colon cancer cell lines (HCT-15) than adriamycin and 5-fluorouracil, with an IC50 value of 2.52, 1.96, and 2.27?μM, respectively. Additionally, structure–activity relationship studies revealed that cytotoxic effects of these oxime derivatives were not only largely dependent upon the size of alkyl chain R1, but also upon substituents R2 of the branch chain, indicating that the strong cytotoxicity of these compounds was ascribed to their appropriate lipophilicity. Collectively, this study could provide available strategy for design and synthesis of 6-substituted 1,4-naphthoquinone oxime derivatives as potential anticancer agents. Graphical abstract: [Figure not available: see fulltext.].
- Huang, Guang,Zhao, Hui-ran,Zhou, Wen,Dong, Jin-yun,Zhang, Qi-jing,Meng, Qing-qing,Zhu, Bao-quan,Li, Shao-shun
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p. 1011 - 1023
(2017/05/12)
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- 2-and 6-methyl-1,4-naphthoquinone derivatives as potential bioreductive alkylating agents
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A number of antineoplastic agents possess both the quinone nucleus and an appropriate substituent that permits them to function as bioreductive alkylating agents. To develop new compounds of this type with unique properties, the authors have synthesized a
- Antonini,Lin,Cosby,Dai,Sartorelli
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p. 730 - 735
(2007/10/02)
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