Discovery of new A- and B-type laxaphycins with synergistic anticancer activity
作者:Weijing Cai、Susan Matthew、Qi-Yin Chen、Valerie J. Paul、Hendrik Luesch
DOI:10.1016/j.bmc.2018.03.022
日期:2018.5
Two new cyclic lipopeptides termed laxaphycins B4 (1) and A2 (2) were discovered from a collection of the marinecyanobacterium Hormothamnion enteromorphoides, along with the known compound laxaphycin A. The planar structures were solved based on a combined interpretation of 1D and 2D NMR data and mass spectral data. The absolute configurations of the subunits were determined by chiral LC-MS analysis
Lobocyclamide B from <i>Lyngbya confervoides</i>. Configuration and Asymmetric Synthesis of β-Hydroxy-α-amino Acids by (−)-Sparteine-Mediated Aldol Addition
作者:John B. MacMillan、Tadeusz F. Molinski
DOI:10.1021/ol025876k
日期:2002.5.1
the first reported occurrence of gamma-hydroxythreonine in a natural peptide. Optically active beta-hydroxy-alpha-amino acids required for configurational analysis of the title compound were prepared using a novel (-)-sparteine-mediated asymmetric aldol addition of N-(diphenylmethylene)glycine tert-butyl ester to aldehydes. The method is general for aliphatic and aryl aldehydes and notable for operational
3-Substituted N-Ethoxycarbonyl aziridine-2-carboxylates are opened in a regio and stereoselective fashion whether in C-2 position by NaX (X = 1, Br) or in C-3 by MgBr2
Total synthesis, structure elucidation and expanded bioactivity of icosalide A: effect of lipophilicity and ester to amide substitution on its bioactivity
The first total synthesis of icosalide A, an antibacterial depsipeptide that is unique in that it contains two lipophilic beta-hydroxy acids, has been achieved by following Fmoc solid-phase peptide synthesis in combination with solution-phase synthesis. The ambiguity in the absolute stereochemistry of icosalide A has been resolved by synthesizing the reported structures and other relevant diastereomers
通过 Fmoc 固相肽合成与溶液相合成相结合,实现了二十内酯 A 的首次全合成,这是一种抗菌缩酚酸肽,其独特之处在于它含有两个亲脂性 β-羟基酸。通过合成已报道的结构和二十内酯的其他相关非对映异构体并比较它们的 NMR 数据,解决了二十内酯 A 绝对立体化学的模糊性。基于 NMR 的二十内酯 A 结构解析揭示了具有交叉链氢键的良好折叠结构,类似于肽中的反平行 β 折叠构象,并显示出脂肪族侧链的协同并置。通过改变亲脂性β-羟基酸残基的组成,合成了12种二十内酯A类似物,并探讨了它们对苏云金芽孢杆菌和树状类芽孢杆菌的生物活性。大多数这些二十内酯类似物对两种细菌的 MIC 均为 12.5 μg mL -1。与树状假单胞菌 (33% ) 相比,艾考沙利特对苏云金芽孢杆菌( 8.3%)的群聚抑制作用最小。此外,这是首次报道艾考沙利特对活跃期的结核分枝杆菌和癌细胞系(如 HeLa 和 ThP1 )具有确实的抑制作用(MIC
Metal halide-mediated opening of three membered rings: enantioselective synthesis of (2S,3R)-3-amino-2-hydroxydecanoic acid and (3R)-3-aminodecanoic acid
Regio and stereoselective opening of three membered rings by metal halides was utilized for the enantioselective synthesis of (2S,3R)-3-amino-2-hydroxydecanoic acid and (3R)-3-aminodecanoic acid. (C) 1997 Published by Elsevier Science Ltd.