- Design, Synthesis, and Pharmacological Evaluation of 2-(2,5-Dimethyl-5,6,7,8-tetrahydroquinolin-8-yl)-N-aryl Propanamides as Novel Smoothened (Smo) Antagonists
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A series of novel Smo antagonists were developed either by directly incorporating the basic skeleton of the natural product artemisinin or by first breaking artemisinin into structurally simpler and stable intermediates and then reconstructing into diversified heterocyclic derivatives, equipped with a Smo-targeting bullet. 2-(2,5-Dimethyl-5,6,7,8-tetrahydroquinolin-8-yl)-N-arylpropanamide 65 was identified as the most potent, with an IC50 value of 9.53 nM against the Hh signaling pathway. Complementary mechanism studies confirmed that 65 inhibits Hh signaling pathway by targeting Smo and shares the same binding site as that of the tool drug cyclopamine. Meanwhile, 65 has a good plasma exposure and an acceptable oral bioavailability. Dose-dependent antiproliferative effects were observed in ptch+/-;p53-/- medulloblastoma cells, and significant tumor growth inhibitions were achieved for 65 in the ptch+/-;p53-/- medulloblastoma allograft model.
- Liu, Gang,Xue, Ding,Yang, Jun,Wang, Juan,Liu, Xiaohua,Huang, Wenjing,Li, Jie,Long, Ya-Qiu,Tan, Wenfu,Zhang, Ao
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- The behaviour of qinghaosu (artemisinin) in the presence of non-heme iron(II) and (III)
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In aprotic solvents with FeCl3, FeCl3/N-acetyl cysteine or FeCl2, qinghaosu (artemisinin) undergoes rearrangement to give the tetrahydrofuran acetate, 4-hydroxydesoxoqinghaosu or the enol lactone as the major product on th
- Haynes, Richard K.,Vonwiller, Simone C.
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- Design and synthesis of novel artemisinin-like ozonides with antischistosomal activity
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To develop new drugs for prevention and treatment of schistosomiasis, a series of novel artemisinin-like ozonides 10 were synthesized via a facile three-step procedure starting with the degraded product of artemisinin (Scheme). The Criegee ozonolysis reac
- Yang, Zhong-Shun,Wu, Wen-Min,Li, Ying,Wu, Yu-Lin
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- The behaviour of qinghaosu (artemisinin) in the presence of heme iron(II) and (III)
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With hemin [chlorprotoporphyrin IX iron(III)] or hemin/cysteine in aqueous MeCN, oxygen loss from the peroxide bridge of qinghaosu takes place to give a precursor to desoxoqinghaosu, a known malaria-inactive metabolite, in low yield. Ring-opened forms of
- Haynes, Richard K.,Vonwiller, Simone C.
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- Potent antimalarial 1,2,4-trioxanes through perhydrolysis of epoxides
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Perhydrolysis of a sterically congested multifunctional epoxide was achieved in ethereal H2O2 with the aid of a recently developed Mo catalyst. The resulting hydroperoxide cyclized to give a 1,2,4-trioxane, which could be readily elaborated into qinghaosu and a range of novel analogues. Some of the compounds with two such trioxane moieties showed in vitro antimalarial activity comparable to or even better than that of artesunate or chloroquine. Molybdenum magic: Facile perhydrolysis of a highly hindered epoxide was achieved with the aid of a molybdenum catalyst. The resulting hydroperoxide was readily converted into a 1,2,4-trioxane, from which natural qinghaosu (QHS, or artemisinin; see scheme) and a range of analogues were constructed. Some of the newly accessed trioxanes showed in vitro antimalarial activity comparable to or even better than that of chloroquine and artesunate. Copyright
- Hao, Hong-Dong,Wittlin, Sergio,Wu, Yikang
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p. 7605 - 7619
(2013/07/04)
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- The role of the 12-carboxylic acid group in the spontaneous autoxidation of dihydroartemisinic acid
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Three of the four steps in the slow spontaneous autoxidation of dihydroartemisinic acid to artemisinin ('ene-type' reaction of molecular oxygen with the Δ4,5 double bond, Hock cleavage of the resulting tertiary allylic hydroperoxide, oxygenation of the enol product from Hock cleavage and cyclization of the resulting vicinal hydroperoxyl-aldehyde to the 1,2,4-trioxane system of artemisinin) are shown to be assisted by the proximity of the 12-carboxylic acid functional group in dihydroartemisinic acid to the functional groups participating in these reactions.
- Sy, Lai-King,Brown, Geoffrey D
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p. 909 - 923
(2007/10/03)
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- Syntheses of dihydroartemisinic acid and dihydro-epi-deoxyarteannuin B incorporating a stable isotope label at the 15-position for studies into the biosynthesis of artemisinin
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[15-13C2H3]-Dihydroartemisinic acid (3a) and [15-13CH3]-dihydro-epi-deoxyarteannuin B (7b), intended for evaluation in vivo as biosynthetic precursors to artemisinin, have been obtained from a reconstructive synthesis. The decalenone acid 8 from acid degradation of artemisinin (1) serves as a common intermediate: following addition of labeled methyl Grignard reagent to 8, either labeled precursor can be prepared in good yield by varying the work-up conditions employed. It is shown that both compounds are prone to autoxidation on storage and that the products of such oxidation and subsequent rearrangement reactions might be confused with bona fide metabolites when using these labeled precursors in feeding experiments designed to determine the biosynthetic route to artemisinin in Artemisia annua.
- Sy, Lai-King,Zhu, Nian-Yong,Brown, Geoffrey D
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p. 8495 - 8510
(2007/10/03)
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- Structure elucidation of arteannuin O, a novel cadinane diol from Artemisia annua, and the synthesis of arteannuins K, L, M and O
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The novel cadinane diol, arteannuin O (1), has been obtained from Artemisia annua and its structure has been established by 2D NMR and X-ray crystallography. A reconstructive synthesis of arteannuin O from artemisinin is described, which also yields the natural products arteannuin K and arteannuin L. Mechanistic considerations have led to the conclusion that the stereochemistry of the 5-hydroxyl group was wrongly assigned when arteannuins K, L and M were first reported as natural products. This was confirmed by derivatization of synthetic arteannuins K, L and M as their Mosher esters.
- Sy, Lai-King,Cheung, Kung-Kai,Zhu, Nian-Yong,Brown, Geoffrey D
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p. 8481 - 8493
(2007/10/03)
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- Epimerization in acid degradation products of artemisinin
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Treatment of artemisinin 1 with acid leads to either a cyclohexane dione degradation product 10, which is a useful intermediate for biosynthetic studies of artemisinin, or to a decalin system which has undergone epimerization 8. It is shown by NMR spectro
- Hui, Shi-Man,Ngo, Koon-Sin,Brown, Geoffrey D.
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p. 3435 - 3442
(2007/10/03)
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