Synthesis and Biological Evaluation of Tamandarin B Analogues
摘要:
[GRAPHICS]The synthesis of two tamandarin B analogues in which the N,O-Me(2)Tyr(5) unit was replaced by N-Me-phenylaianine (N-MePhe(5)) and (S)-2(methylamino)-3-(naphthalen-2-yl)propanoic acid (N-MeNaphth(5)) is described. The choice of the macrocyclization site was crucial to achieve satisfactory macrolactamization. Coupling between norstatine (Nst(1)) and threonine (Thr(6)) afforded only a 15% yield, while lactamization between proline (Pro(4)) and the aromatic moiety could be achieved in 65% yield.
the presence of a threonine-derived bioxazole core and an N-(1,1-dimethyl)allyl ("reverse prenyl") valine residue. In the context of our synthesis, efficient new strategies for the preparation of these segments were developed. The synthesis of two epimers of muscoride A allowed the unambiguous assignment of the relative and absolute configuration of the natural product by NMR and optical rotation analyses
The first enantioselective synthesis of cytotoxic marine natural product palau’imide and assignment of its C-20 stereochemistry
作者:Hong-Qiao Lan、Yuan-Ping Ruan、Pei-Qiang Huang
DOI:10.1039/c0cc00452a
日期:——
racemization-free synthesis of methyl 5-benzyl-3-methyltetramate via alkylation, and used in the first asymmetric synthesis of palau'imide (1). This allowed the establishment of the hitherto unknown stereochemistry at the C-20 of palau'imide as S.
The total synthesis of spiruchostatin A was accomplished, unambiguously confirming its structure. Key steps included the use of the Nagao thiazolidinethione auxiliary for a diastereoselective acetate aldol reaction and as an activated acylating agent for amide formation, and macrolactonization by the Yamaguchi protocol. Spiruchostatin A is shown to have biological activity similar to that of FK228, a potent histone deacetylase (HDAC) inhibitor in clinical trials. The spiruchostatin A analogue, epimeric at the beta-hydroxy acid, is inactive, highlighting the importance of stereochemistry at this position for interactions with HDACs.
An efficient synthesis of the tamandarin B macrocycle
作者:Kenneth M. Lassen、Jisun Lee、Madeleine M. Joullié
DOI:10.1016/j.tetlet.2009.12.091
日期:2010.3
A reliable, high yielding cyclization protocol for the macrocycle of tamandarin B is presented. This strategy will facilitate the synthesis of side chain analogs. (C) 2009 Elsevier Ltd. All rights reserved.