Ta-Hsien Chuang

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Bioassay-guided fractionation of the MeOH extract of the leaves of Grevillea robusta led to the isolation of six new 5-alkylresorcinols, gravicycle (1), dehydrogravicycle (2), bisgravillol (3), dehydrobisgravillol (4), dehydrograviphane (5), and methyldehydrograviphane (6), as well as eight known compounds. The structures of these compounds were determined(More)
The sex pheromone of the mealybug, Planococcus minor was isolated by fractionation of crude pheromone extract obtained by aeration of virgin females. The pheromone was identified as the irregular terpenoid, 2-isopropyl-5-methyl-2,4-hexadienyl acetate, by mass spectrometry, microchemical tests, and (1)H NMR spectroscopy. The stereochemistry of the pheromone(More)
A cryptopleurine analogue, 7-methoxycryptopleurine, a phenanthroquinolizidine, was first found to exert potent anti-inflammatory activity in vitro and in vivo as well as have remarkable cytotoxic activity against cancer cells. The non-planar structure between the two major moieties, phenanthrene and indolizidine/quinolizidine, played a crucial role in the(More)
Tylophorine, a representative phenanthroindolizidine alkaloid from Tylophoraindica plants, exhibits anti-inflammatory and anti-cancerous growth activities. However, the underlying mechanisms of its anti-cancer activity have not been elucidated and its effects on cell cycle remain ambiguous. Here, we reveal by asynchronizing and synchronizing approaches that(More)
The separation of an extract prepared from the stems of the previously uninvestigated Hibiscus taiwanensis led to the isolation of three new phenylpropanoid esters, (7S,8S)-demethylcarolignan E (1), hibiscuwanin A (2), hibiscuwanin B (3), in addition to eight known ones. The structures of these compounds were elucidated by spectroscopic and chemical(More)
The total synthesis of alkaloids phenanthroindolizidine 1a, tylophorine 1b, and phenanthroquinolizidine 1c, has been achieved in 46%, 49%, and 42% overall yield, respectively, starting from the corresponding phenanthrene-9-carboxaldehyde. Compound exhibited potent inhibition activity in three human cancer cell lines, with IC(50) values ranging from 104 to(More)
Cephalantheropsis gracilis afforded five new compounds: cephalanthrin-A (1), cephalanthrin-B (2), cephathrene-A (3), cephathrene-B (4), methyl 2-(aminocarbonyl) phenylcarbamate (5), and 52 known compounds. The structures of the new compounds were determined by spectroscopic analysis. Among the compounds isolated, tryptanthrin (6), phaitanthrin A (7),(More)
A series of amido-substituted triazolopyrrolo[2,1-c][1,4]benzodiazepine (PBDT) derivatives was synthesized from isatoic anhydride, and their cytotoxicity against the MRC-5 and Mahlavu cell lines was evaluated. The results suggest that compound PBDT-7i with the meta-trifluoromethylbenzoyl substituent can selectively inhibit the growth of Mahlavu cells and(More)
Three new compounds: Graviquinone (1), cis-3-hydroxy-5-pentadecylcyclohexanone (2), and methyl 5-ethoxy-2-hydroxycinnamate (3), and thirty-eight known compounds were isolated and identified from the leaves of Grevillea robusta. The structures of these compounds were determined by spectroscopic and chemical transformation methods. Graviquinone (1) showed the(More)
The thermal cyclization of 3,4-diphenylbuta-1,3-dienyl isocyanates 1, generated in situ from the corresponding azides, was investigated using iodine as a catalyst. Diphenylpyridinones 2, phenylnaphthalenes 3, and indenes 4 were produced via intramolecular ring closure. The nature of the substituents on the phenyl rings was found to be crucial to the(More)