Es wird gezeigt, dass man durch Kondensation von basisch substituierten Estern mit o-Oxy-acylphenonen und Ringschluss der entstandenen 1,3-Diketone zu Chromonen gelangt, die in 2-Stellung basisch substituiert sind. Die Synthese liess sich auch mit N-acetylierten Estern durchführen.
Nanocrystalline copper(II) oxide efficiently catalyzed the conjugate addition of aliphatic amines to α,β-unsaturated compounds to produce β-amino compounds with excellent yields under mild reaction conditions. Similarly, Glycine esters are obtained in good yields by the insertion of α-diazoacetate into N–H bonds of amines. The catalyst is used for three cycles with minimal loss of activity.
A Proposal for Using Mild Bases in the Preparation of Optically Pure Peptides
作者:Shumpei Sakakibara、Masumi Itoh
DOI:10.1246/bcsj.40.656
日期:1967.3
p-nitrophenyl ester was studied with various tertiary amines; N, N-dialkylglycine esters and N-ethylmorpholine were found to induce less racemization than triethylamine. Furthermore, these mild bases were strong enough in many cases to liberate free amino acid or peptide esters from their salts. It was also confirmed that a mixture of an amino acid or peptide ester salt and such a mild base could be used in the
用各种叔胺研究了 N-羧基苯甲氧基-S-苄基-L-半胱氨酸对硝基苯酯的碱催化外消旋化反应;发现 N, N-二烷基甘氨酸酯和 N-乙基吗啉比三乙胺诱导更少的外消旋化。此外,这些弱碱在许多情况下足够强以从它们的盐中释放游离氨基酸或肽酯。也证实了氨基酸或肽酯盐和这种弱碱的混合物可以代替先前制备的游离酯用于肽合成,并且在与酰基氨基酸的偶联反应过程中几乎没有观察到外消旋化活性酯。Anderson 的外消旋化试验也是通过混合酸酐程序用这些弱碱代替三乙胺进行的;发现弱碱在光学纯度方面产生更好的结果。
Cationic lipid-conjugated bis-arylidene oxindole derivatives as broad-spectrum breast cancer-selective therapeutics
作者:Md Yousuf、Kathyayani Sridharan、Tanushree Mishra、Namita S. Mahadik、Rajkumar Banerjee、Susanta S. Adhikari
DOI:10.1016/j.bioorg.2023.106395
日期:2023.4
available chemotherapeutic agents in achieving clinical success are in maintaining systemic bio-distribution and avoiding non-specific adverse effects. Bis-arylideneoxindoles are estrogenreceptor (ER)-selective bioactive molecules with moderate potency. In here, we have designed, synthesized and evaluated a series of twin aliphatic chain cationic lipid-conjugated bis-arylideneoxindole molecules with variations
乳腺癌是一种异质性恶性肿瘤,在治疗反应、总生存期等方面存在广泛差异。可用化学治疗剂实现临床成功的主要挑战是维持全身生物分布和避免非特异性不良反应。双亚芳基羟吲哚是具有中等效力的雌激素受体 (ER) 选择性生物活性分子。在这里,我们设计、合成和评估了一系列双脂肪链阳离子脂质共轭双亚芳基羟吲哚分子,这些分子具有不同的接头性质、碳间隔基长度和疏水双链。我们观察到,在各种结构类似物中,含有 C8 双链的分子PGC8、S2C8和S3C8在不同的癌细胞系中显示出有效的癌细胞选择性细胞毒性,IC 50范围为 4 至 7 µM。这些分子在 ER + 乳腺癌细胞而非非癌细胞中选择性地诱导细胞凋亡、ROS 产生和 G1/S 期细胞周期抑制。此外,这些分子形成了同质的自组装体,显示出具有正表面电荷的有效流体动力学直径。自组装还显示出突出的癌细胞选择性摄取和 DNA 结合能力。因此,我们已经证明成功地将地塞米松掺入自组装体中,并且即使在
Efficient and Highly Selective Copper(II) Transport across a Bulk Liquid Chloroform Membrane Mediated by Lipophilic Dipeptides
作者:Marco C. Cleij、Paolo Scrimin、Paolo Tecilla、Umberto Tonellato
DOI:10.1021/jo9703257
日期:1997.8.1
Several structurally simple N-monoalkylated and -dialkylated dipeptides made of alpha-amino acids Gly, Phe, and Leu, 1-11, were synthesized and investigated as carriers for the transport of Cu(II), Zn(II), and Ni(II) from an aqueous pH = 5.6 buffer source to a 0.1 M HCl receiving phase across a bulk chloroform membrane. The proton-driven translocation was followed during the process by analyzing the metal ion concentrations in the three phases. The transport efficiency depends on the ease of formation of a neutral complex with Cu(II) (the peptide group and carboxylic acid being deprotonated) at the source-chloroform interface and on that of its disruption by protonation at the receiving phase: the carrier's Lipophilicity favors the metal ion uptake and not the release. By modulating the length of the N-alkyl chains and the hydrophobicity of the dipeptide moiety, a quite remarkable transport efficiency was observed for Cu(II), in most cases superior to that of the industrial extractant Kelex 100. Moreover, using L,L- and L,D-N-octyl-PheLeu as carriers, remarkable diastereomeric effects were observed in the rate of uptake and release of Cu(II) ion although the differences mutually compensate in the overall transport rate. Under the conditions used the carriers are much less effective in the translocation of Zn(II) and Ni(II) and their transport efficiency drops dramatically in the presence of Cu(II), the latter being favored by factors of 1.2 x 10(3) and > 10(4), respectively. Such very high selectivities depend on the fact that only Cu(II) among other transition metal ions Can form neutral complexes at the pH value of the source phase.