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Archive for the ‘Hot articles’ Category

HOT: Bionanoparticles as building blocks

12 Aug 2011

Nature has designed many biogenic systems with exquisite symmetries and complexities on the nanometer scale, such as viruses, ferritins and enzyme complexes. These structures have acted as building blocks on which researchers have been able to develop bionanoparticles with a wide variety of applications including biosensors, electronic nanodevices, drug delivery agents and vaccine carriers, amongst others.

In this OBC Perspective Qian Wang and colleagues highlight some of the recent progress in the chemical modification and molecular engineering of these bionanoparticles with the aim of sparking new discussions and inspiring the development of many new materials in the future.

Graphical abstract: Altering the landscape of viruses and bionanoparticles

Interested? Then why not read this comprehensive review now. It is free to download for the next four weeks!

Altering the landscape of viruses and bionanoparticles
L. Andrew Lee, Huong Giang Nguyen and Qian Wang
Org. Biomol. Chem., 2011, DOI: 10.1039/C1OB05700F

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HOT: Using precursor-directed biosynthesis to open new fronts in the battle against cancer

11 Aug 2011

Supplying an organism with modified precursor materials for biosynthesis is a great way of hijacking the synthetic machinery of an organism to make the compounds you want. In this paper Cormac Murphy and colleagues from University College Dublin and Ecole Normale Superieure demonstrate that precursor-directed biosynthesis is a convenient way to create analogs of rumbrin with tunable potency and selectivity, also showing that the 3-chloropyrrole moiety is not absolutely essential for biological activity in this class of polyenes. One of the compounds prepared showed dramatically improved activity against lung cancer cells.

Interested? Read this article in OBC, it is free to access for the next four weeks!

Production of anticancer polyenes through precursor-directed biosynthesis
Benjamin R. Clark, Stephen O’Connor, Deirdre Fox, Jacques Leroy and Cormac D. Murphy
Org. Biomol. Chem., 2011, Advance Article

DOI: 10.1039/C1OB05667K

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HOT: Novel drugs fight back against MRSA

05 Aug 2011

The enormous success of antibiotics is seriously threatened by the development of resistance to many drugs available on the market. So the search for new antibiotics that are less prone to resistance is on.

Antimicrobial peptides (AMPs) are a possible solution that has attracted considerable attention but they have some drawbacks including high cost of manufacturing. Now Steven Firestine and colleagues at Wayne State University in the US have examined the potential of a new class of benzophenone-based membrane targeted antibiotics (BPMTAs).

Firestine shows that these agents release potassium ions from treated bacteria which results in disruption of the bacterial membrane potential. This membrane-targeted disruption means that BPMTAs have excellent activity against antibiotic-resistant strains like MRSA and VRSA.

The team have demonstrated the promising potential of these agents by using them to cure mice of a lethal MRSA infection. They were also unable to develop a mutant resistant to the agents.

Interested? Read the article in OBC that is free to access for the next four weeks!

Examination of a synthetic benzophenone membrane-targeted antibiotic
Sunil K. Vooturi, Mahender B. Dewal and Steven M. Firestine
Org. Biomol. Chem., 2011, DOI: 10.1039/C1OB05643C

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HOT: vinylogous Mukaiyama-Michael reaction for synthesis of γ-subsituted butenolides

27 Jul 2011

The butenolide skeleton is one of the more common to natural products and bioative compounds, thus its synthesis has afforded much attention from synthetic chemists in recent years. Here, Xiamong Feng and colleagues from the Key Laboratory of Green Chemistry and Technology at Sichuan University have devised a simple route that affords the desired γ-butenolide compounds in high yields with high levels of selectivity.

By using a chiral N,N‘-dioxide-scandium catalyst in an asymmetric vinylogous Mukaiyama–Michael reaction they were able to form highly functionalized chiral γ-substituted butenolides with broad substrate scope, with up to 92% ee. The pathway is air stable and produces product on a gram scale.

For the full details download the article – it’s free to access for the next four weeks:

Highly enantioselective synthesis of γ-substituted butenolides via the vinylogous Mukaiyama–Michael reaction catalyzed by a chiral scandium(III)–N,N′-dioxide complex
Qi Zhang, Xiao Xiao, Lili Lin, Xiaohua Liu and Xiaoming Feng
Org. Biomol. Chem., 2011, Advance Article
DOI: 10.1039/C1OB05558E

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Hot: New tools to fight HIV

27 Jul 2011

New potentially useful therapeutic tools for the sexually transmitted HIV infection have been identified by Anna Bernardi at the University of Milan, Franck Fieschi and colleagues in France, Spain and Italy.

DC-SIGN and Langerin are two C-type lectins involved in the initial steps of HIV infection: the former acts as a viral attachment factor and facilitates viral invasion of the immune system, while the latter has a protective effect. Bernardi and Fieschi have successful synthesised potential antiviral compounds targeted against DC-SIGN using a common fucosylamide anchor.

Their DC-SIGN affinity was found to be similar to that of the natural ligand Lewis-X (LeX). The compounds were also found to be selective for DC-SIGN and to interact only weakly with Langerin. All these results point to the potential for these molecules to be used as therapeutic tools to fight the disease.

This hot piece of synthesis is currently free to access for four weeks:

Second generation of fucose-based DC-SIGN ligands : affinity improvement and specificity versus Langerin
Manuel Andreini, Daniela Doknic, Ieva Sutkeviciute, José J. Reina, Janxin Duan, Eric Chabrol, Michel Thepaut, Elisabetta Moroni, Fabio Doro, Laura Belvisi, Joerg Weiser, Javier Rojo, Franck Fieschi and Anna Bernardi
Org. Biomol. Chem., 2011, DOI: 10.1039/C1OB05573A,

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HOT: carbene catalysis to make courmarin derivatives

11 Jul 2011

A new nucleophilic heterocyclic carbene mediated transformation of 2H-chromene-3-carboxaldehydes has been reported by Vijay Nair, CSIR, et al.

The team were attempting to make endocyclic homoenolates from 2H-chromene-3-carboxaldehyde, but instead discovered a novel transformation which resulted in 3-methyl coumarin. Coumarins have demonstrated important bioactives and therefore the group envisage that this reaction may be a useful future route to coumarin derivatives.

This hot piece of synthesis is currently free to access for four weeks:

A novel NHC-catalyzed transformation of 2H-chromene-3-carboxaldehydes to 3-methyl-2H-chromen-2-ones
Vijay Nair, C. R. Sinu, R. Rejithamol, K. C. Seetha Lakshmi and Eringathodi Suresh
Org. Biomol. Chem., 2011, Advance Article
DOI: 10.1039/C1OB05325F

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Work on bacterial lipoteichoic acids in the press!

28 Jun 2011

The hot Perspective article from Richard Schmidt, Christian Pedersen, Yan Qiao and Ulrich Zähringer has been picked up by several media outlets interested in their work on bacterial lipoteichoic acids.

The team reported the synthesise of several LTAs – which are important important constituents of the cell wall of Gram-positive bacteria – and carried out studies on their biological activity. More work is needed to understand the recognition of LTAs by the innate immune system, but this work suggests that it is indeed the lectin pathway that LTAs interact with and paves the way for an improved understanding of infection by Gram-positive bacteria.

Here are some of the places the research has been highlighted:

Download the original Perspective article here for all the details:

Chemical synthesis of bacterial lipoteichoic acids: An insight on its biological significance
Richard R. Schmidt, Christian M. Pedersen, Yan Qiao and Ulrich Zähringer
Org. Biomol. Chem., 2011, 9, 2040-2052
DOI: 10.1039/C0OB00794C

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Hot: solid to soluble biolabelling

24 Jun 2011

Fluorescent bio-probes, polypeptide tags and reporter proteins have become invaluable tools in life science research. So labelling of natural biological molecules with fluorescent organic dyes has become a popular area of research. But while many fluorphores perform well in organic solvents, it’s not so easy to make ones that work well the aqueous media required for biological applications.

Now, Anthony Romieu and colleagues at the University of Rouen, France, have devised an easy and efficient solid-phase synthesis to obtain rapidly water soluble choromophores and fluorophores in a highly pure form. They report the first successful use of N-Fmoc-a-sulfo-b-alanine as a solid-phase peptide synthesis building block, which could open the way to the future development of promising direct protein labelling.

Graphical abstract: N-Fmoc-α-sulfo-β-alanine: a versatile building block for the water solubilisation of chromophores and fluorophores by solid-phase strategy

To read more, download the article – it’s free to access for the next four weeks:

N-Fmoc-α-sulfo-β-alanine: a versatile building block for the water solubilisation of chromophores and fluorophores by solid-phase strategy
Anthony Romieu, Thomas Bruckdorfer, Guillaume Clavé, Virgile Grandclaude, Cédrik Massif and Pierre-Yves Renard
Org. Biomol. Chem., 2011, DOI: 10.1039/C1OB05730

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HOT: a neat new route to the integrastatin core

22 Jun 2011

Integrastatins display micromolar inhibition of the HIV-1 integrase enzyme, halting replication of the virus. Medicinal chemists are therefore very interested in being able to synthesise these natural products, and their analogues, to investigate potential HIV therapies.

The total synthesis of either integrastatin A or B is yet to be reported, but several groups have reported the synthesis of the tetracycle core, Brian Stoltz and colleagues Caltech being the latest. Their synthesis differs from previous reports by utilising a palladium-catalyzed oxidative cyclization. Their four-step route produces the tetracycle core in 30% overall yield.

This HOT piece of synthesis is free to access for 4 weeks:

A rapid and convergent synthesis of the integrastatin core
Pamela M. Tadross, Pradeep Bugga and Brian M. Stoltz
Org. Biomol. Chem., 2011, Advance Article
DOI: 10.1039/C1OB05725A

You may also like to look at the other reports of the integrastatin core synthesis published in RSC journals:

Unexpected Z-stereoselectivity in the Ramberg–Bäcklund reaction of diarylsulfones leading to cis-stilbenes: the effect of aryl substituents and application in the synthesis of the integrastatin nucleus
Jonathan S. Foot, Gerard M. P. Giblin, A. C. Whitwood and R. J. K. Taylor
Org. Biomol. Chem., 2005, 3, 756-763

An expeditious one-step entry to the tetracyclic core of integrastatins
C. V. Ramana, Challa Nageswara Reddy and Rajesh G. Gonnade
Chem. Commun., 2008, 3151-3153

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HOT: glycosyldisulfide lectin ligands

11 Jun 2011

S-glycosides are resistant to hydrolytic cleavage, which gives them a distinct pharmacological advantage over O-glycosides as ligands for lectins, but inherently present different biological activity. This HOT article evaluates the ability of dithiodigalactoside (DTDG) – which was identified through a dynamic combinatorial library approach in a previous study – to protect human cells from toxin binding.

Jésus Jiménez-Barbero, CSIC, and an international team of researchers show that DTDG is capable of selecting between the mistletoe toxin and human lectins and conclude that glycosyldisulfides have potential as chemical platform for inhibitor design.

Interested? The article is free to download for the next 4 weeks:

Symmetric dithiodigalactoside: strategic combination of binding studies and detection of selectivity between a plant toxin and human lectins
Sonsoles Martín-Santamaría, Sabine André, Eliza Buzamet, Rémi Caraballo, Gloria Fernández-Cureses, Maria Morando, João P. Ribeiro, Karla Ramírez-Gualito, Beatriz de Pascual-Teresa, F. Javier Cañada, Margarita Menéndez, Olof Ramström, Jesús Jiménez-Barbero, Dolores Solís and Hans-Joachim Gabius
Org. Biomol. Chem., 2011, Advance Article
DOI: 10.1039/C0OB01235A

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