Publications by authors named "Hilaire V Kemami Wangun"

Pancreatic cancer, the 4th leading cause of cancer death in the US, is highly resistant to all current chemotherapies, and its growth is facilitated by chronic inflammation. An important mediator of inflammation is the nuclear factor kappa B (NFκB), a transcription factor that regulates over 500 genes including the regulation of anti-apoptotic proteins, cell cycle progression and cytokine production. NFκB is constitutively activated in pancreatic cancer cells contributing to their resistance to apoptosis and high metastatic potential.

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The real mechanism of the Skraup-Doebner-Von Miller quinoline synthesis remains controversial and not well understood despite several mechanistic studies reported on the matter. A series of unexpected and unusual 5,6,7,8,9,10-hexahydro-6,6-pentamethylenephenanthridines and 2,3,4,5-tetrahydro-4,4-tetramethylene-1H-cyclopenta[c]quinolines have been obtained through the Skraup-Doebner-Von Miller quinoline synthesis. On the basis of these unexpected results and in agreement with some of the previously reported quinoline syntheses, an alternative mechanistic pathway is proposed for this variant of the reaction.

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Because of their extreme instability, it is generally difficult to synthesize and fully characterize open chain peroxides, also known as peroxols. In our attempt to investigate the mechanism of the Skraup-Doebner-Von Miller quinoline synthesis, we were able to obtain an unusual open chain peroxy-quinoline, namely, 4-(8-ethoxy-2,3-dihydro-1H-cyclopenta[c]quinolin-4-yl)butane-1-peroxol (1), and its alcohol counterpart, namely 4-(8-ethoxy-2,3-dihydro-1H-cyclopenta[c]quinolin-4-yl)butan-1-ol (2) obtained as a side product during the same reaction. Although structurally similar, these two compounds appeared to display some very distinct physical and spectroscopic characteristics.

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Bioactivity-guided fractionation of metabolites from the crinoid Holopus rangii led to the discovery of two new phenanthroperylenequinone derivatives, gymnochromes E (1) and F (2). Gymnochrome E showed cytotoxic activity toward the NCI/ADR-Res with an IC(50) of 3.5 microM.

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Three new tetramic acid derivatives, epicoccamides B-D, together with the known epicoccamide, were isolated from an Epicoccum sp. associated with the tree fungus Pholiota squarrosa. The structures of the new compounds were elucidated on the basis of their physical data and chemical degradation.

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Investigation of the metabolic profile of a fungus (Epicoccum sp.) isolated from the fruiting body of the tree fungus Pholiota squarrosa led to the discovery of two novel tetramic acid derivatives, epicoccarine A (2) and B (3), as well as a new pyridone alkaloid, epipyridone (1), with an unusually cyclized side chain. It appears that 1 is biogenetically derived from the ring expansion of 2 followed by a proposed hetero-Diels-Alder reaction.

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By bioassay-guided isolation, phenylpropanoid-derived polyketides, including an unusual 5-methyl-3(2H)-furanone derivative (inotilone) with potent cyclooxygenase (COX) and xanthone oxidase (XO) inhibitory activities were obtained from the fruiting body of the mushroom Inonotus sp.

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Two pentacyclic triterpenes, 1alpha,3beta-dihydroxybauer-7-en-28-oic acid (1) and 3beta-hydroxybauer-7-en-28-oic acid (2), together with sitosterol-3-beta-O-d-glucopyranoside and stigmasterol have been isolated from the bark of the plant Maesopsis eminii. Their structures have been elucidated by spectroscopic methods. One of the triterpenes (1) is new, and its structure was confirmed by X-ray crystallographic analysis.

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The new compound lignoren (1) was isolated from Trichoderma lignorum HKI 0257 by chromatographic methods. This metabolite has a santalane-like structure, which was elucidated by mass spectrometric and NMR spectroscopic investigations. Lignoren (1) shows a moderate narrow-spectrum of antibacterial and antifungal activity.

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