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ABSTRACT: Based on highly selective and irreversible Hg(2+)-promoted desulfurization reaction, a new and simple phenanthroimidazole-type sensor was prepared and exhibited high selectivity towards Hg(2+) ion over other metal ions, accompanied by transformation of a weakly fluorescent thioamide moiety (colorless) to a highly fluorescent amide one (blue), with a 136-fold increase in fluorescent intensity in aqueous solution with a pH span 2.57-9.12.
Bioorganic & medicinal chemistry letters 03/2013; · 2.65 Impact Factor
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ABSTRACT: In continuation of our program aimed at the discovery and development of natural products-based insecticidal agents, twenty-three new fraxinellone-based hydrazone derivatives were smoothly prepared from fraxinellone via regioselectively allylic oxidation in the presence of selenium dioxide or chromium trioxide under microwave irradiation and subsequent condensation with hydrazides or hydrazines. Their insecticidal activity was evaluated against the pre-third-instar larvae of Mythimna separata Walker in vivo. Especially compounds 6d and 7a displayed the most pronounced insecticidal activity compared with toosendanin, a commercial botanical insecticide derived from Melia azedarach.
Bioorganic & medicinal chemistry letters 07/2012; 22(17):5384-7. · 2.65 Impact Factor
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ABSTRACT: Based upon highly selective and irreversible Hg(2+) -promoted deprotection of the dithioacetal reaction, a new water-soluble "turn on" fluorescent chemosensor 1 was prepared and exhibited high selectivity and sensitivity towards the Hg(2+) ion over other heavy and transition-metal ions in pure water by transforming a weakly fluorescent precursor (colorless) to a highly fluorescent aldehyde (yellow-green; see figure) with a 155-fold increase in fluorescent intensity.
Chemistry 07/2012; 18(36):11188-91. · 5.93 Impact Factor
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ABSTRACT: In continuation of a program aimed at the discovery and development of natural products-based insecticidal agents, two series of novel fraxinellone-based esters were synthesized by modification at the C-4 or C-10 position of fraxinellone and evaluated for their insecticidal activity against the pre-third-instar larvae of Mythimna separata in vivo. An efficient method for the stereoselective synthesis of 4α-hydroxyfraxinellone from fraxinellonone was developed, and the steric configuration of 6h was unambiguously confirmed by X-ray crystallography. Among 37 compounds, some derivatives displayed potent insecticidal activity; especially compounds 6h, 6q, 6t, and 7q showed more promising insecticidal activity than toosendanin, a commercial botanical insecticide derived from Melia azedarach . This suggested that introduction of the fluorine atom on the phenyl ring could lead to a more potent compound than one possessing chlorine or bromine. Meanwhile, introduction of the heterocyclic fragments at the C-4 or C-10 position of fraxinellone was essential for their insecticidal activity. This will pave the way for further design, structural modification, and development of fraxinellone as an insecticidal agent.
Journal of Agricultural and Food Chemistry 06/2012; 60(28):7016-21. · 2.82 Impact Factor
