The synthesis of five new chiral macrocyclic peptidomimetic naphthalenophanes, together with two open-chain derivatives, is described. The cyclization step is accomplished in good yields without the use of high dilution or template techniques. The new compounds have been photophysically studied by means of steady-state fluorescence spectroscopy. It has been found that the smaller the ring size, the higher the emission quantum yield from the excited charge-transfer state (CTS, exciplex) and the lower the fluorescence from the locally excited state (LES). The occurrence of exciplex fluorescence is noteworthy as the electron-donating groups are secondary amine moieties, which do not normally form emissive exciplexes. (C) 2007 Elsevier Ltd. All rights reserved.
Synthesis of Chiral Tropopodands Having L-Amino Acid Moieties and Ability of Their Metal Complexes as an Asymmetric Catalyst
摘要:
Optical active tropopodands (10 and 11) having neutral L-amino acids and L-histidine moieties were synthesized. Within their metal complexes, Pd complexes of histidine-tropopodands (11b and 11c) bearing bulky amide moieties showed good ability as an asymmetric catalyst in conjugate addition.
Molecular Hydrogels from Bolaform Amino Acid Derivatives: A Structure-Properties Study Based on the Thermodynamics of Gel Solubilization
作者:Vicent J. Nebot、José Armengol、Johan Smets、Susana Fernández Prieto、Beatriu Escuder、Juan F. Miravet
DOI:10.1002/chem.201103193
日期:2012.3.26
Insight is provided into the aggregation thermodynamics associated to hydrogel formation by molecular gelators derived from L‐valine and L‐isoleucine. Solubility data from NMR measurements are used to extract thermodynamic parameters for the aggregation in water. It is concluded that at room temperature and up to 55 °C, these systems form self‐assembled fibrillar networks in water with quite low or
Mechanistic Insight into the Lability of the Benzyloxycarbonyl (Z) Group in<i>N</i>-Protected Peptides under Mild Basic Conditions
作者:Marta Tena-Solsona、César A. Angulo-Pachón、Beatriu Escuder、Juan F. Miravet
DOI:10.1002/ejoc.201400154
日期:2014.6
protecting group undermildbasicconditions at room temperature is explained by a mechanism based on anchimeric assistance. It is found that the vicinal amide group stabilises the tetrahedral intermediate formed after nucleophilic addition of hydroxide to the carbonyl of the Z group. This effect operates in N-protected tripeptides and tetrapeptides but Z-protected dipeptides are stable under the same conditions
苄氧羰基 (Z) 保护基团在室温温和碱性条件下出乎意料的不稳定可通过基于嵌合辅助的机制来解释。发现邻酰胺基团稳定了在氢氧化物与 Z 基团的羰基亲核加成后形成的四面体中间体。这种效应在 N 保护的三肽和四肽中起作用,但 Z 保护的二肽在相同条件下是稳定的,因为邻位酰胺 NH 通过与末端羧酸根部分的分子内 H 键合而被阻断。
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
Synthesis, spectroscopic studies and biological evaluation of acridine derivatives: The role of aggregation on the photodynamic efficiency
作者:Carles Felip-León、Olga Martínez-Arroyo、Santiago Díaz-Oltra、Juan F. Miravet、Nadezda Apostolova、Francisco Galindo
DOI:10.1016/j.bmcl.2018.02.005
日期:2018.3
a strong tendency to aggregate in water. Biological assays were conducted with two cell types: hepatoma cells (Hep3B) and human umbilical vein endothelial cells (HUVEC). Photodynamic therapy (PDT) studies carried out with Hep3B cells showed that non-aggregating compound 2 showed photoxicity, ascribed to the production of singlet oxygen, being aggregating compound 1 photochemically inactive. On the other
Diamine acylation with amino acid derivatives: an example of proximity effect in organic reactivity induced by supramolecular aggregation
作者:Carles Felip-León、María D. Segarra-Maset、Beatriu Escuder、Juan F. Miravet
DOI:10.1016/j.tetlet.2015.01.094
日期:2015.2
Unexpected high yields of diamide 3 are obtained in the reaction of 1,3-propanediamine with an activated ester of L-valine (1) under adverse proportions of the reactants, namely in the presence of an excess of 1,3-propanediamine. It is observed using different conditions that the yield of difunctionalized compound is considerably higher than that expected from a statistical distribution of products. Proximity effects associated to supramolecular interactions explain the described reactivity. (C) 2015 Elsevier Ltd. All rights reserved.