Sarah Dixon – Organic & Biomolecular Chemistry Blog

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Hot: Elegant (-)-erycibelline synthesis

14 Oct 2011

Chu-Yi Yu and colleagues present the first stereoselective synthesis of (-)-Erycibelline in this OBC hot article.

(-)-Erycibelline is a naturally occurring dihydroxynortropane alkaloid isolated from the Chinese herb medicine Erycibe elliptilimba, which is used to treat rheumatic disease and is a useful pain-killer.

Yu’s team first synthesized a cyclic nitrone with both nitrone and aldehyde functional groups as the key intermediate by organometallic addition of nitrone followed by oxidation and deprotecton. Subsequent SmI2-induced intramolecular reductive coupling and reductions produced (-)-Erycibelline with good yields.

Graphical abstract: A concise stereoselective synthesis of (−)-erycibelline

This neat approach to the nortropane skeleton is versatile and could allow general access to hydroxylated nortropane alkaloids and their analogues, which could be beneficial for treating other diseases.

Download the article now to read more details of this elegant synthesis – it’s free to access for 4 weeks!

A concise stereoselective synthesis of (−)-erycibelline
Z.-L. Zhang, S. Nakagawa, A. Kato, Y.-M. Jia, X.-G. Hu and C.-Y. Yu
Org. Biomol. Chem., 2011, DOI: 10.1039/C1OB06244A

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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: 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: 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: 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: Radical route to lactams

27 Apr 2011

Lactams are often used as building blocks for antibiotics, such as penicillin. Now Hiroshi Matsubara, Ilhyong Ryu and colleagues have investigated an exciting radical route to produce them.

They show that acyl radicals can react as electrophiles in ionic type addition reactions with amines, which leads to cyclisation forming a series of lactams. Depending on the N-substituent (good or not good leaving group) reaction occurs via rare 1,4-H shift or via a formal homolytic substitution at nitrogen leading to interesting new compounds.

Download the paper now to read more about the synthetic scope and theoretical findings. It is free to access until 25^th May.

This article will be included in the OBC special issue in memory of Athel Beckwith: Free Radical Chemistry. Coming soon

Radical carbonylation of ω-alkynylamines leading to α-methylene lactams. Synthetic scope and the mechanistic insights
Ilhyong Ryu, Takahide Fukuyama, Mami Tojino, Yoshitaka Uenoyama, Yuka Yonamine, Nozomi Terasoma and Hiroshi Matsubara
Org. Biomol. Chem., 2011, 9, 3780-3786
DOI: 10.1039/C1OB05145H

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HOT: Radical cyclisations made simple

25 Mar 2011

Read the latest OBC hot paper in which Thorsten Bach and colleagues use a hydrogen bond template to carry out highly enantioselective radical cyclisations.

Bach’s template works as a steric shield preventing the approach of a reagent from one side of the molecule. Using the method Bach was able to demonstrate radical cyclisations of quinolines with 94–99% ee.

This is an important investigation with wide reaching consequences and will be of interest to many organic chemists. Its free to download until 21^st April.

This paper will be included in the OBC special web themed issue on radical chemistry that will be published soon. Keep an eye on it!

Enantioselective radical cyclisation reactions of 4-substituted quinolones mediated by a chiral template
Aline Bakowski, Martina Dressel, Andreas Bauer and Thorsten Bach
Org. Biomol. Chem., 2011, DOI: 10.1039/C0OB01272F

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HOT: Butterflies aid cancer research

04 Mar 2011

Qing-min Wang and colleagues at Nankai University, China, describe the first complete synthesis of a recently identified natural product with intriguing anticancer activity.

Papilistatin was isolated from a Taiwan butterfly in 2010 and was found to inhibit leukaemia cell growth. This inspired Wang to undertake the synthetic challenge of producing the compound in the lab. Constructing the phenanthrene ring system proved tricky explains Wang but after many attempts at oxidative coupling, he discovered that radical cyclisation was the key.

Read more about this synthesis in the article which is free to download until 31^st March.

First total synthesis of Papilistatin
Meng Wu, Ling Li, An-Zheng Feng, Bo Su, De-min Liang, Yu-xiu Liu and Qing-min Wang
Org. Biomol. Chem., 2011, DOI: 10.1039/C0OB01214A,

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HOT: Two-faced nucleosides combat RNA viruses

25 Jan 2011

Ribavirin is a nucleoside drug used to treat RNA viral infections such as Hepaptitis C, which interferes with RNA metabolism required for viral replication. But its efficiency is relatively low, so in a HOT article just published, Yang He and colleagues at Sichuan University report the synthesis of two new nucleosides and their improved anti-viral activity.

He’s nucelosides contain structural features of two naturally occurring components of RNA (guanine and cytosine). This unique feature allows it to interfere with the RNA virus via hydrogen bond pairing with either guanine or cytosine, as well as allowing it to be recognised by viral enzymes more efficiently than ribavirin.

If you want to find out more about these interesting bio-active nucleosides download the article now! It’s free to access until the 18th February.

Synthesis of Janus type nucleoside analogues and their preliminary bioactivity
Hao-Zhe Yang, Mei-Ying Pan, Da-Wei Jiang and Yang He
Org. Biomol. Chem., 2011, DOI: 10.1039/C0OB00495B

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