Organic & Biomolecular Chemistry Blog

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

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,

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

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.

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