- Synthesis and antimalarial activity of febrifugine derivatives
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The regioisomers (2a,b) of the piperidine ring of febrifugine (1a) and isofebrifugine (1b) were synthesized from 4-allyl-3-piperidone (5). Reduction of 5 afforded a mixture of the trans and cis alcohols (6a,b) without diastereoselectivity; this result differentiated it from the reduction of 2-allyl-3-piperidone (14). The antimalarial di-activity of 2a,b and related compounds was tested.
- Takeuchi,Koike,Azuma,Nishioka,Abe,Kim,Wataya,Harayama
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- Synthesis and biological evaluation of isofebrifugine analogues
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Isofebrifugine, as a kind of natural quinazolinone alkaloid with important physiological activities and good pharmacological effects, was isolated from a Chinese medicinal plant, Chang Shan (Dichroa febrifuga). In this paper, the synthesis of a series of novel isofebrifugine analogues was accomplished by employing the N-alkylation of 4(3H)-quinazolinones with benzyl (3aR,7aR)-rel-2-(bromomethyl)hexahydrofuro[3,2-b]pyridine-4(2H)carboxylates and the subsequent N-deprotection. These analogues were characterized by1 H NMR,13 C NMR and HRMS spectra. The MTT assay was used to examine the inhibitory effects of these analogues on the growth of human hepatoma cells (HepG2). The results indicated that some halogenated or hemiketal analogues showed interesting inhibition activity.
- Zhang, Jinjin,Huang, Baohua,Lu, Yujing,Li, Wenbin,Zhuang, Zichong,Ke, Donghua,Zhong, Jingpeng,Zhou, Jinlin,Chen, Qian
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p. 1004 - 1010
(2019/11/22)
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- Metabolites of febrifugine and its synthetic analogue by mouse liver S9 and their antimalarial activity against Plasmodium malaria parasite
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Quinazolinone type alkaloids, febrifugine (1) and isofebrifugine (2), isolated from Dichroa febrifuga roots, show powerful antimalarial activity against Plasmodium falciparum. Unfortunately, their emetic effect and other undesirable side effects have precluded their clinical use for malaria. Because of their antimalarial potency, analogues were searched for, with the goal of preserving the strong antimalarial activity, while dramatically reducing side effects. We expected that compounds useful in drug development would exist in metabolites derived from 1 and Df-1 (3), the condensation product of 1 with acetone, by mouse liver S9. Feb-A and -B (4 and 5) were isolated as the major metabolites of 1. In addition to 4 and 5, feb-C and -D (6 and 7) were also purified from the metabolic mixture of 3. Compounds 4 and 5 were compounds oxidized at C-6 and C-2 of the quinazolinone ring of 1, respectively. Compounds 6 and 7, derived from 3, also bear febrifugine type structures in which the 4″- and 6″-positions of the piperidine ring of 1 were oxidized. In vitro antimalarial and cytotoxic tests using synthetically obtained racemic 4-6 and enantiomerically pure 7 demonstrated that 4 and 6 had antimalarial activity against P. falciparum, of similar potency to that of 1, with high selectivity. The antimalarial activity of 5 and 7, however, was dramatically decreased in the test. The in vitro antimalarial activity of analogues 22 and 43, which are stereoisomers of 4 and 6, was also evaluated, showing that 22 is active. The results suggest that basicity of both the 1- and the 1″-nitrogen atoms of 1 is crucial in conferring powerful antimalarial activity. Racemic 4 and 6 exhibited powerful in vivo antimalarial activity against mouse malaria P. berghei, and especially, no serious side effects were observed with 4. Thus, the metabolite 4 appears to be a promising lead compound for the development of new types of antimalarial drugs.
- Hirai, Shingo,Kikuchi, Haruhisa,Kim, Hye-Sook,Begum, Khurshida,Wataya, Yusuke,Tasaka, Hidehisa,Miyazawa, Yuriko,Yamamoto, Keisuke,Oshima, Yoshiteru
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p. 4351 - 4359
(2007/10/03)
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- Synthesis of D/L-febrifugine and D/L-isofebrifugine
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Racemic compounds (1 and 2) of the antimalarial agents febrifugine (D-1) and isofebrifugine (D-2) were synthesized using an unusual Claisen rearrangement of allyl enol ether 6 and the stereoselective reduction of 2- allylpiperid-3-one 8. This method is widely applicable to the synthesis of febirifugine derivatives.
- Takeuchi, Yasuo,Hattori, Mayumi,Abe, Hitoshi,Harayama, Takashi
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p. 1814 - 1818
(2007/10/03)
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- Total synthesis of dl-febrifugine and dl-isofebrifugine
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Racemic compounds (1 and 2) of the antimalarial agents febrifugine (d- l) and isofebrifugine (d-2) were synthesized using an unusual Claisen rearrangement of allyl enol ether (7) and the stereoselective reduction of 2- allyl-3-piperidone (8). This method is widely applicable to the synthesis of derivatives needed to study the structure-activity relationship of febrifugine.
- Takeuchi, Yasuo,Abe, Hitoshi,Harayama, Takashi
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p. 905 - 906
(2007/10/03)
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