源自氨基酸的简单拟肽分子在乙腈中与间位和对位双(溴甲基)苯反应,非常有效地产生大环结构。环化反应不需要高稀释技术,并且似乎对形成的大环的大小不敏感。通过 (1)H NMR、单晶 X 射线衍射、荧光测量和分子力学获得的数据分析表明,折叠构象可以预先组织系统以实现有效的环化。分析了在折叠构象存在下分子内氢键和疏溶剂效应所起的作用。
New chiral tetraaza ligands for the efficient enantioselective addition of dialkylzinc to aromatic aldehydes
作者:M. Isabel Burguete、Jorge Escorihuela、Santiago V. Luis、Agustí Lledós、Gregori Ujaque
DOI:10.1016/j.tet.2008.07.099
日期:2008.10
enantioselective addition of dialkylzinc to aldehydes. These bis(amino amide) ligands show high enantioselectivity in the addition of organozincs to aromatic aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Ligand 4b (N,N′-bis(N-l-valinyl)-1,3-diaminopropane, with an aliphatic spacer with 3C atoms) catalyzed the addition of Et2Zn
A series of C2-symmetric bridged silsesquioxanes derived from L- and D-valine have been designed and synthesized. They were capable of forming physical gels in organic solvents such as ethanol, THF, and 1,4-dioxane. These silsesquioxanes formed helical bundles in 1,4-dioxane. With respect to the helical sense, a clear odd–even effect was found in the carbon number of the central alkylene segment. The silsesquioxanes with odd number alkylene segments derived from L-valine tended to self-assemble into right-handed helical bundles. On the contrary, those with even number alkylene segments tended to form left-handed helical bundles. Moreover, enantiomers derived from D-valine showed the opposite helical sense. The p : d ratio played an important role in the determination of helical sense. After sol–gel polycondensation under catalysts such as HCl, NaOH, and TBAF, helical hybrid silica bundles were identified in FESEM images. The helical sense of the bundles was sensitive to the catalysts and reaction conditions. Hybrid silica sponges showing both superoleophilic and superhydrophobic properties were obtained under a HCl diffusion procedure.
一系列源自L-和D-缬氨酸的C2对称桥接硅烷氧烷已被设计和合成。这些化合物能够在乙醇、四氢呋喃和1,4-二氧烷等有机溶剂中形成物理凝胶。这些硅烷氧烷在1,4-二氧烷中形成螺旋束。在螺旋方向上,发现中央烷基段的碳原子数存在明显的奇偶效应。源自L-缬氨酸的奇数烷基段硅烷氧烷倾向于自组装成右手螺旋束。相反,偶数烷基段的则倾向于形成左手螺旋束。此外,源自D-缬氨酸的对映体表现出相反的螺旋方向。p : d 比例在确定螺旋方向上发挥了重要作用。在HCl、NaOH和TBAF等催化剂的作用下,经过溶胶-凝胶聚缩合后,通过FESEM图像可以识别出螺旋混合硅氧化物束。这些束的螺旋方向对催化剂和反应条件敏感。在HCl扩散过程中获得了显示超级亲油和超级疏水特性的混合硅海绵。
Synthesis and Evaluation of Pseudopeptidic Fluorescence pH Probes for Acidic Cellular Organelles: In Vivo Monitoring of Bacterial Phagocytosis by Multiparametric Flow Cytometry
作者:M. Isabel Burguete、Francisco Galindo、M. Angeles Izquierdo、José-Enrique O'Connor、Guadalupe Herrera、Santiago V. Luis、Laura Vigara
DOI:10.1002/ejoc.201000854
日期:2010.11
applications of this family of probes, macrocyclic pseudopeptide 2 was used to monitor the phagocytosis of a culture of GFP-labelled bacteria by human monocytic cells U937 using flowcytometry as the analytical tool. It was found that the occurrence of bacterial killing was concomitant with the production of reactive oxygen species and a drop in pH, the latter monitored indirectly by macrocyclic sensor
合成了一类新的荧光蒽 pH 探针,并对其进行了化学表征,并通过稳态和时间分辨荧光光谱研究了它们的光物理特性。已经在溶液中研究了这些化合物监测 pH 值的能力,并且发现分子 1-12 可以充当 4.6 和 6.5 范围内 pH 值的荧光传感器。该范围对应于描述了有限数量探针的细胞中酸性细胞器的 pH 值(pH 4.5-6.0)。每个传感器的酸碱行为略有不同,具体取决于分子中存在的胺附近的取代基的性质。Thus, the pK a of this family of compounds can be finely tuned by the appropriate selection of the synthetic building blocks at the design stage. 为了测试该探针家族的潜在诊断应用,使用流式细胞术作为分析工具,使用大环假肽 2 来监测人类单核细胞 U937
Supramolecular gel formation and self-correction induced by aggregation-driven conformational changes
作者:Francisco Rodríguez-Llansola、Juan F. Miravet、Beatriu Escuder
DOI:10.1039/b816234d
日期:——
The formation of self-assembled fibrillar networks by low molecular weight peptidomimetics containing a Pro-Val moiety is reported; insight into the aggregation mechanism is provided revealing that it is associated to an unfolding process and that a fibrillar network formed under kinetic control can self-correct into a thermodynamically stable one.
The catalytic performance of triazolyl‐based moleculargels was investigated in the Huisgen 1,3‐dipolar cycloaddition of alkynes and azides. Low‐molecular‐weight gelators derived from l‐valine were synthesized and functionalized with a triazole fragment. The resultant compounds formed gels either with or without copper, in a variety of solvents of different polarity. The gelators coordinated CuI and