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
The Enantioselective Synthesis of ?-Amino Acids, their ?-hydroxy derivatives, and theN-terminal components of bestatin and microginin
作者:Charles W. Jefford、James McNulty、Zhi-Hui Lu、Jian Bo Wang
DOI:10.1002/hlca.19960790426
日期:1996.6.26
(3R)-3-aminobutanoic acids 12a–e (ee > 99%). Electrophilic hydroxylation of 8 ( 19; Scheme 3), subsequent iodo-esterification ( 21; Scheme 4), and nucleophilic alkylation and phenylation afforded, after saponification and deprotection, a series of 4-substituted (2S, 3R)-3-amino-2-hydroxybutanoic acids 24 including the N-terminal acids 24e ( =3) and 24f ( =4) of bestatin and microginin (de > 95%), respectively
Homochiral lithium amides for the asymmetric synthesis of β-amino acids
作者:Stephen G. Davies、Narciso M. Garrido、Dennis Kruchinin、Osamu Ichihara、Luke J. Kotchie、Paul D. Price、Anne J. Price Mortimer、Angela J. Russell、Andrew D. Smith
DOI:10.1016/j.tetasy.2006.05.008
日期:2006.7
Secondary homochiral lithium amides derived from α-methylbenzylamine undergo highly diastereoselective conjugate additions to a range of α,β-unsaturated esters. The corresponding β-aminoacids are readily liberated by successive N-debenzylation and ester hydrolysis, furnishing (R)-β-amino butyric acid, (R)-β-amino pentanoic acid, (S)-β-leucine, (R)-β-amino octanoic acid, (S)-β-phenylalanine, (S)-β-tyrosine
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
L-Aspartic acid by regioselective modification of the α-carboxylic acid group, namely N-tosylation, anhydride formation, reduction, iodo-esterification, alkylation, and deprotection afforded a series of γ-alkyl β-aminobutyric acids of the R configuration (ee>99%).
Process for preparing carboxylic acid using surfactant-modified enzyme
申请人:Miyata Hiroyuki
公开号:US20090117626A1
公开(公告)日:2009-05-07
The present invention relates to a process for preparing a carboxylic acid using a surfactant-modified enzyme which comprises selectively reacting water and a carboxylic acid ester, provided that triglyceride is excluded, in an organic solvent in the presence of a surfactant-modified enzyme.