- An Expeditious Modular Hybrid Strategy for the Diversity-Oriented Synthesis of Lamellarins/Azalamellarins with Anticancer Cytotoxicity
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A modular hybrid strategy has been developed for the diversity-oriented synthesis of lamellarins/azalamellarins. The common pentacyclic pyrrolodihydroisoquinoline lactone/lactam core was formed via the Michael addition/ring closure (Mi-RC) and the copper(I) thiophene-2-carboxylate (CuTC)-catalyzed C-O/C-N Ullmann coupling. Subsequent direct functionalization at C1, DDQ-mediated C5C6 oxidation, and global deprotection of all benzyl-type O- and N-protecting groups furnished the desired lamellarins/azalamellarins. The late-stage functionalization at C1 provided a handle to accommodate a wider scope of functional groups as they need to tolerate only the DDQ oxidation and global deprotection. Moreover, with the C1-H pyrrole as the late-stage common intermediate, it was also possible to divergently exploit not only its nucleophilic nature to react with some electrophilic species but also some transition-metal-catalyzed cross-coupling reactions (via the intermediacy of the C1-iodopyrrole) to incorporate diversity at this position. Overall, this strategy simplifies the preparation of lamellarins/azalamellarins; including the Mi-RC, these C1-structurally diverse analogues could be prepared efficiently in 6-7 steps from the easily accessed 1-acetoxymethyldihydroisoquinoline and β-nitrocinnamate. Some selected azalamellarins were evaluated for their inhibitory effect against HeLa cervical cancer cells. An acute induction of intrinsic apoptosis was detected and may lead to growth suppression of or cytotoxicity against cancer cells.
- Klumthong, Kanawut,Chalermsub, Papornchanok,Sopha, Pattarawut,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 14883 - 14902
(2021/09/13)
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- METHOD FOR PRODUCING LAMELLARIN AND DERIVATIVE THEREOF
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The present application discloses a method for producing lamellarin and a derivative thereof, which is able to greatly shorten the synthesis path of the lamellarin and the derivative thereof, and to improve the yield of the lamellarin and the derivative t
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Paragraph 0110; 0121
(2018/10/19)
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- Construction of Pentacyclic Lamellarin Skeleton via Grob Reaction: Application to Total Synthesis of Lamellarins H and D
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An efficient construction of phenyl-substituted coumarin-pyrrole-isoquinoline-fused pentacycle via base-promoted Grob-type coupling of 3-nitrocoumarin and papaverine in a sealed tube is reported. This reaction is further applied to the total synthesis of lamellarin H in three linear steps and lamellarin D in eight linear steps with overall yields of 31% and 14%, respectively.
- Manjappa, Kiran B.,Lin, Jhih-Min,Yang, Ding-Yah
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p. 7648 - 7656
(2017/07/26)
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- Facile and Divergent Synthesis of Lamellarins and Lactam-Containing Derivatives with Improved Drug Likeness and Biological Activities
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With the goal to improve the aqueous solubility of lamellarins, the lactone ring in their skeleton was replaced with a lactam moiety in azalamellarins. However, the reported synthetic route produced such derivatives in very low yields. Hence, this study focused on developing an efficient simplified total synthetic scheme that could furnish both azalamellarins and the parent lamellarins from the same pyrrole ester intermediates. Subsequent comparative profiling revealed that the introduced lactone-to-lactam replacement rendered these molecules less lipophilic, whereas their cancer cytotoxicity remained equipotent to that of the parent compounds. Interestingly, their inhibitory activity was significantly enhanced towards the multifaceted GSK-3β enzyme. Our results clearly demonstrate the therapeutic potential of this promising class of marine-derived natural products and justify their further development, especially into anticancer agents.
- Theppawong, Atiruj,Ploypradith, Poonsakdi,Chuawong, Pitak,Ruchirawat, Somsak,Chittchang, Montakarn
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p. 2631 - 2650
(2016/02/09)
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- Total syntheses of lamellarin D and H. The first synthesis of lamellarin-class marine alkaloids
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Total syntheses of marine polyaromatic alkaloids, lamellarin D (1) and H (2), are described. The pentacyclic lamellarin ring system was constructed by N-ylide mediated pyrrole ring formation and subsequent lactonization of 4 obtained by an assembly of known benzylisoquinoline 5, benzoate 6 and ethyl bromoacetate.
- Ishibashi, Fumito,Miyazaki, Yuka,Iwao, Masatomo
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p. 5951 - 5962
(2007/10/03)
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