Nathalie Horner – Organic & Biomolecular Chemistry Blog

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Chemical biology and medicinal: Potential agents to treat Alzheimer’s disease

10 Sep 2012

Scientists in Germany have worked on optimising compounds that reduce the formation of amyloid β-peptides, which play a crucial role in the development and progression of Alzheimer’s disease. The team varied the membrane anchor, spacer and pharmacophore building blocks on BACE1 inhibitors to make tripartite structures (assembled by covalent coupling of BACE1 inhibitors with membrane anchors via suitable spacers).

Several BACE1 inhibitors have already been reported, but here, the team has shown that the cellular activity of small-molecule BACE1 inhibitors can be significantly increased by membrane targeting via a spacer with a raftophilic membrane anchor.

Optimisation of BACE1 Inhibition of Tripartite Structures by Modification of Membrane Anchor, Spacer and Pharmacophore – Development of Potential Agents for the Treatment of Alzheimer’s Disease
Hans-Joachim Knölker
DOI: 10.1039/C2OB26103K

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Caffeine test to tell if decaf coffee really is decaffeinated

20 Aug 2012

Graphical abstract Scientists in Switzerland have synthesised a dye (3,4:3’,4’-bibenzo[b]thiophene-2,2’-disulfonate) that can be used as a sensitive and selective molecular probe for the fluorimetric detection of caffeine in water.

The system’s sensitivity and selectivity are higher than those of current synthetic caffeine sensors, so much so that caffeine can be detected in the sub-millimolar concentration range, the researchers claim. The team prepared sensor test strips on which a change in emission colour on addition of caffeine was easy to detect by the naked eye.

A ratiometric fluorescence sensor for caffeine
Nicolas Luisier, Albert Ruggi, Stephan N. Steinmann, Laurane Favre, Nicolas Gaeng, Clémence Corminboeuf and Kay Severin
DOI: 10.1039/C2OB26117K

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Organic: A mechanism-based fluorescence transfer assay for examining ketosynthase selectivity

23 Jul 2012

US scientists have developed a cheap and simple way to examine the selectivity of the ketosynthase domain found in polyketide synthases.

Polyketide synthases are multicomponent enzyme systems that make polyketide natural products. They have received attention from researchers hoping to harness their potential as a platform for generating new and improved therapeutics. But the field of polyketide engineering has faced a constant struggle to overcome often strict substrate selectivities of the critical biosynthetic enzymes.

The new fluorescence-based method is much simpler and cheaper than previously used radiolabelling techniques and should enable improved understanding of how these biosynthetic machines function.

A Mechanism-Based Fluorescence Transfer Assay for Examining Ketosynthase Selectivity
Gitanjeli Prasad, Lawrence S. Borketey, Tsung-Yi Lin and Nathan A. Schanrr
Org. Biomol. Chem., 2012, Accepted Manuscript
DOI: 10.1039/C2OB26008E

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Organic: Natural products with anti-inflammatory, sedative, and antispasmodic activities synthesised

09 Jul 2012

Scientists in Switzerland have carried out the asymmetric synthesis of the 12-membered lactone alkaloids (+)-vertine and (+)-lythrine (structurally related and possessing a range of bioactivities), which has so far proved a challenge.

Peter Kundig and his group employed a range of strategies and novel tactics to overcome the synthetic challenge, and the strain in the two diastereomeric 12-membered lactone alkaloids was ultimately overcome via Z-selective alkene metathesis.

Asymmetric synthesis of (+)-vertine and (+)-lythrine
Peter Kundig, Laetitia Chausset-Boissarie, Roman Arvai, Graham Cumming and Laure Guénée
DOI: 10.1039/C2OB25880C

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Organic: Steps towards making new natural products

29 Jun 2012

UK scientists have synthesised the core ring structure of the fargenin/fargenone family of (biologically active) natural products. This, they say, is the first synthetic step towards this family of compounds. The strategy they devised uses an elegant cascade concept, which while unfortunately not leading to the desired natural product itself, still proves the concept validity and provides a first entry to this class of natural products.

A strategy for the synthesis of the fargenone/fargenin family of natural products: Synthesis of the tricyclic core
Ross Matthew Denton
DOI: 10.1039/C2OB25489A

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Organic: New compounds for actinide and lanthanide separation

22 Jun 2012

Scientists in the Netherlands and Germany have synthesised a series of new pyrazine substituted ligands that are promising for actinide separation.

The team used the ligands to differentiate trivalent actinides from lanthanides, with a very good selectivity for Am³⁺ over Eu³⁺ with separation factors up to 40 at pH 1 at 0.01 mol/L ligand concentration.

The ligands are resistant to strong acids and water soluble, which makes them ideal for the innovative SANEX concept (Selective ActiNide Extraction).

The team says: ‘It is basically a DIAMEX (DIAMide EXtraction) process (An(III) and Ln(III) coextraction) with selective back extraction of An(III) from the loaded organic phase. Instead of a water-soluble complexing agent such as diethylene triamine pentaacetic acid, which requires in most cases buffering agents to adjust the pH, the search is for stronger acid resistant water-soluble ligands.’

Palladium–catalyzed cross-coupling of various phosphorus pronucleophiles with chloropyrazines: synthesis of novel Am(III)-selective extractants
W. Verboom, Nicolai I. Nilishkin, Jurriaan Huskens, Giuseppe Modolo, Jana Assenmacher and Andreas Wilde
DOI: 10.1039/C2OB25787D

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Nanoscience: Regulating the traffic across cells membranes

11 Jun 2012

Nanopore-forming materials have many potential applications in chemistry and biology, including DNA sequencing. However, only very limited designs of synthetic nanopores exist in the literature. US scientists have made circular molecules made of sugars that can stack on top of one another to form a transmembrane pore and act as carriers to shuttle the guest molecules across the membrane.

Hydrogen bond-assisted macrocyclic oligocholate transporters in lipid membranes
Lakmini Widanapathirana, Xueshu Li and Yan Zhao
DOI: 10.1039/C2OB25301A

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Organic & Biomolecular Chemistry Blog

Author Archive

Chemical biology and medicinal: Potential agents to treat Alzheimer’s disease

Caffeine test to tell if decaf coffee really is decaffeinated

Organic: A mechanism-based fluorescence transfer assay for examining ketosynthase selectivity

Organic: Natural products with anti-inflammatory, sedative, and antispasmodic activities synthesised

Organic: Steps towards making new natural products

Organic: New compounds for actinide and lanthanide separation

Nanoscience: Regulating the traffic across cells membranes

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