- New reactivities of deltaline analogs: An efficient O-demethylation at C-1 and an unusual extrusion of the C-14 atom
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O-Demethylation at C-1 in the C19-diterpenoid alkaloids is very challenging. In this paper, it was firstly observed that 10-OH group in deltaline (1) is a determining factor for the O-demethylation reaction. After removal of this hydroxyl group, 1-O-methyl group in the corresponding deltaline analogs can be readily removed by treatment with HBr-HOAc. Meanwhile, the C-14 atom in bromides 18 or 20 can be extruded under basic condition probably via a sequence, including Grob fragmentation, aerobic oxidation, deformylation, and SN2 nucleophilic substitution, to give enone 21 (70%) and oxetane 22 (14%). The structure of compound 22 was confirmed by X-ray crystallographic analysis of its derivative 21.
- Tang, Pei,Chen, Qi-Feng,Wang, Ling,Chen, Qiao-Hong,Jian, Xi-Xian,Wang, Feng-Peng
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- Generating skeletal diversity from the C19-diterpenoid alkaloid deltaline: A ring-distortion approach
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The development of new drugs calls for large collections of diverse molecules with considerable complexity. Ring distortion of natural products provides an efficient and facile approach to access new architectures with intriguing biological activities, by harnessing their inherent complexity. In this study, such a strategy has been explored on an abundant C19-diterpenoid alkaloid, deltaline, enabling the synthesis of 32 new derivatives bearing a broad spectrum of unique scaffolds. Extensive spectroscopic studies including X-ray crystallographic analyses strongly supported the structures of the obtained novel skeletons, which present comparable opportunities with the great contributions made by nature for discovery of new lead compounds.
- Chen, Qi-Feng,Wang, Feng-Peng,Liu, Xiao-Yu
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- REACTIONS OF LYCOCTONINE ALKALOIDS CONTAINING A 7,8-METHYLENEDIOXY GROUP WITH Na IN LIQUID AMMONIA
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The reactions of 6-dehydroeldelidine and 6-dehydrodelcorine with sodium in liquid ammonia have been studied.Structures have been put forward for the compounds obtained.Features of the fragmentation of these compounds under electron impact are discussed.
- Narzullaev, A. S.,Yunusov, M. S.,Sirotenko, E. G.,Rashkes, Ya. V.,Sabirov, S. S.
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p. 450 - 455
(2007/10/02)
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- REACTION OF C19-DITERPENE ALKALOIDS WITH SODIUM IN LIQUID AMMONIA
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The reaction of C19 -diterpene alkaloids with sodium and liquid ammonia in the presence and in the absence of a proton donor - an alcohol - has been investigated.In the absence of the proton donor the hydroxy group is converted into a carbonyl group, which is characteristic only for C-6-hydroxy or -acetoxy derivatives.
- Narzullaev, A. S.,Yunusov, M. S.,Moiseenkov, A. M.,Sabirov, S. S.
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p. 321 - 323
(2007/10/02)
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