Artificial tongues and leaves

The objective with synthetic multifunctional nanoarchitecture is to create large suprastructures with interesting functions. For this purpose, lipid bilayer membranes or conducting surfaces have been used as platforms and rigid-rod molecules as shape-persistent scaffolds. Examples for functions obtained by this approach include pores that can act as multicomponent sensors in complex matrices or rigid-rod π-stack architecture for artificial photosynthesis and photovoltaic

Stylopine: A potential natural metabolite to block vascular endothelial growth factor receptor 2 (VEGFR2) in osteosarcoma therapy

Vascular endothelial growth factor (VEGF) signals cell survival, cell migration, osteogenesis, cell proliferation, angiogenesis, and vascular permeability by binding to VEGF receptor 2 (VEGFR-2). Osteosarcoma is the most common primary bone cancer, majorly affects young adults. Activation of VEGFR-2 signaling is a therapeutic target for osteosarcoma. The present study aimed to evaluate the potency of stylopine in regulation of the VEGFR-2 signaling pathway and its anti-tumour effect human MG-63 osteosarcoma cells. The in silico study on benzylisoquinoline alkaloids was carried out for analyzing and shortlisting of compounds using a virtual screening, Lipinski’s rule, bioavailability graphical RADAR plot, pharmacokinetics, toxicity, and molecular docking studies. Among the benzylisoquinoline alkaloids, stylopine was selected and subjected to in-vitro studies against human MG-63 osteosarcoma cells. Various experiments such as MTT assay, EtBr/AO staining, mitochondrial membrane potential assessment, transwell migration assay, gene expression analysis by a quantitative real time polymerase chain reaction (qRT-PCR) method, SDS-PAGE followed by immunoblotting were performed to evaluate its anti-tumour effect as compared to standard axitinib. The MTT assay indicates that stylopine inhibits cell proliferation in MG-63 cells. Similarly, as confirmed by the EtBr/Ao staining method, the MMP assay indicates that stylopine induces mitochondrial membrane damage and apoptosis as compared to axitinib. Moreover, stylopine inhibits the VEGF-165 induced MG-63 cell migration by a trans-well migration assay. The immunoblotting and qRT-PCR analysis showed that stylopine inhibits the VEGF-165 induced VEGFR2 expression in MG-63 cells. It is concluded that stylopine has potential to regulate VEGFR2 and can inhibit osteosarcoma cells to offer a new drug candidate for the treatment of bone cancer in future

First enantioselective total synthesis of the angucyclinone-type antibiotic YM-181741

A simple and efficient strategy for angucyclinone anti­biotics is described with the disclosure of first total synthesis of YM-181741

Solubilising groups: a conceptual equivalent of protecting groups in organic synthesis

In this brief essay, one of the most common and least appreciated challenge in the field is addressed. Few chemists, particularly supramolecular chemists, exist who are not all too familiar with solubility problems during the synthesis of new molecules. Solubility problems are inherent to the synthesis of molecules that are made to build supramolecular architectures because the same intermolecular interactions that cause the problem are later on essential for the final self-assembly of the system of interest. Naturally, many solutions exist for a problem that occurs so frequently. They are used as daily routine in many laboratories, the temporary attachment of hydrophobic bulk of various size and nature being the most common. However, contrary to the comparable situation with protecting groups, these solubilising groups are generally underappreciated, often communicated orally as one of those precious 'lab secrets' that nobody really takes serious but everybody really needs to get things running and reach the relevant part of the research project. Here, we briefly try to summarise latent concepts concerning solubilising groups, focusing particularly on questions concerning quantitative aspects and the removal of solubilising groups for self-assembly with pre-, post- or in situ desolubilisation, and provide a simple practical example with tert-butyldiphenylsilyl as an illustrative solubilising group

Synthesis of a bicyclo[5.3.1]undecene by a facile domino enyne cross-metathesis/IMDA

An efficient domino cross-enyne metathesis/intramolecular Diels–Alder reaction is demonstrated for the construction of a bicyclo[5.3.1]undecene

Rapid and mild synthesis of functionalized naphthalenediimides

Core-substituted naphthalenediimides (NDIs) are not often used in functional materials despite excellent properties because the harsh conditions used for their synthesis are incompatible with structural diversity. Here, we report rapid access to blue, red, and yellow NDIs under mild conditions with tolerance toward the additional presence of pertinent functional groups

Experimental evidence for the functional relevance of anion-pi interactions

Attractive in theory and confirmed to exist, anion–π interactions have never really been seen at work. To catch them in action, we prepared a collection of monomeric, cyclic and rod-shaped naphthalenediimide transporters. Their ability to exert anion–π interactions was demonstrated by electrospray tandem mass spectrometry in combination with theoretical calculations. To relate this structural evidence to transport activity in bilayer membranes, affinity and selectivity sequences were recorded. π-acidification and active-site decrowding increased binding, transport and chloride > bromide > iodide selectivity, and supramolecular organization inverted acetate > nitrate to nitrate > acetate selectivity. We conclude that anion–π interactions on monomeric surfaces are ideal for chloride recognition, whereas their supramolecular enhancement by π,π-interactions appears perfect to target nitrate. Chloride transporters are relevant to treat channelopathies, and nitrate sensors to monitor cellular signaling and cardiovascular diseases. A big impact on organocatalysis can be expected from the stabilization of anionic transition states on chiral π-acidic surfaces

Artificial tongues and leaves

The objective with synthetic multifunctional nanoarchitecture is to create large suprastructures with interesting functions. For this purpose, lipid bilayer membranes or conducting surfaces have been used as platforms and rigid-rod molecules as shape-persistent scaffolds. Examples for functions obtained by this approach include pores that can act as multicomponent sensors in complex matrices or rigid-rod π-stack architecture for artificial photosynthesis and photovoltaics