Organic & Biomolecular Chemistry Blog

RSC Organic Division Poster Symposium 2014 one month left to submit

03 Sep 2014

Calling all final year organic chemistry PhD students

There is only one month left to submit your abstract for the RSC Organic Division’s poster symposium, headline sponsored by F. Hoffmann-La Roche, Ltd.

When & where?

The symposium will take place at The Royal Society of Chemistry, Burlington House, London on Monday 01 December 2014 and offers you the chance to showcase your research to your peers, leading academics and industrial chemists.

Prizes

There will be a first prize of £500, two runner-up prizes of £250, and a “selected by Industry Prize” also of £500.

Closing date for submissions is Wednesday 01 October 2014.

For more information and to submit your abstract go to http://rsc.li/organic-poster

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Myriad Multiplicity in Nitroenamine Multicomponent Methodology

28 Aug 2014

By James Anson.

Posted on behalf of Jennifer Lee, guest web writer for Organic & Biomolecular Chemistry

Not many molecules can claim to be both a Michael donor and Michael acceptor while containing a good leaving group as is the case with nitroketene-N,S-acetals like N-methyl-S-methyl nitroethylene (NMSM), broadly categorized as nitroenamines.

As a double actor in the pseudo three-component reaction investigated by Rao and Parthiban, moieties of NMSM react three times in two roles: twice as a nucleophile and once as an electrophile. The other components in the same pot included the aromatic aldehyde and catalytic 2-aminopyridine.

The methodology generates an alternate route from the classic Hantzsch reaction to the 1,4-dihydropyridine (DHP) platform with a broader scope and purification by recrystallization. Advantageously, 1,4-DHPs are calcium channel blockers and hydride sources for reduction.

The functionally-rich NMSM component conveniently diversifies DHP which could lead to more potent medicinal applications or pesticides.

The two inherent diversity points on the platform arose from the aldehyde and amine precursors. Additional diversity from amine substitution of the built-in sulfide leaving group created a total of 29 unique 1,4-DHP possibilities.

Specifically, they synthesized a neonictinoid insecticide analogue to the popular nitenpyram compound to constrain the alkene to the cis-isomer with muted toxicity to mammals.

Overall, leveraging an electronically versatile synthon like NMSM in a multicomponent reaction leads to enhanced diversity for analoging with myriad compounds that could perform better than those currently available.

To find out more see:

One-pot pseudo three-component reaction of nitroketene-N,S-acetals and aldehydes for synthesis of highly functionalized hexa-substituted 1,4-dihydropyridines
H. Surya Prakash Rao and A. Parthiban
DOI: 10.1039/c4ob00628c

Jennifer Lee is currently a Ph.D. candidate in Dr. George Kraus’ organic chemistry lab at Iowa State University. Her research focuses on designing methodologies to transform carbohydrate-derived biomass into biorenewable commodity and specialty chemicals. The creation of a versatile platform technology led to diverse and industrially-relevant aromatic compounds to work toward a more sustainable future.

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Vaccines for heroin

19 Aug 2014

By Richard Kelly.

Arun Ankush Tanpure, a graduate student at IISER Pune, India, writes on a recent OBC article

The number of deaths due to heroin overdoses has severely increased in last decade, and regular consumption of heroin leads to serious health concerns.

Vaccination is one of the emerging choices among heroin rehabilitation therapies. In general, these vaccines contain heroin-like hapten as a pharmacophore that acts as an antagonist. This antagonist has high affinity for heroin receptors but does not activate them, hence reverses the effects of heroin. Because of inherent chemical instability, when entered in to bloodstream these anti-heroin drugs rapidly metabolise into several by-products, which makes development of effective vaccines against heroin particularly challenging.

Recently an American research group at National Institute on Drug Abuse (NIDA) lead by Professor Kenner Rice has reported the synthesis and immunological evaluation for a series of haptens.

The team has emphasised the hydrolytic stability of hapten scaffolds and envisioned that hapten with amido groups at both the C3 and C6 positions should be more stable than a hapten with an ester in one of those positions. Insertion of a 3-amino group and the construction of a C-6α-(2-oxo-propyl) group stereoselectively was the challenging task towards the synthesis of designed hapten derivatives. The group has tackled the synthetic hurdle by adopting convergent synthesis approach and validating the stereochemistry by single X ray crystallography.

Furthermore, in vivo Immunological studies of all three new synthetic haptens reveals that one derivative DiAmHap (3) is chemically more stable and better candidate for a heroin vaccine than 6-PrOxyHap (1) and DiPrOxyHap (2). This work is a very positive step towards the development of vaccines for heroin abuse.

Synthesis and immunological effects of heroin vaccines
Fuying Li, Kejun Cheng, Joshua F. G. Antoline, Malliga R. Iyer, Gary R. Matyas, Oscar B. Torres, Rashmi Jalah, Zoltan Beck, Carl R. Alving, Damon A. Parrish, Jeffrey R. Deschamps, Arthur E. Jacobson and Kenner C. Rice
DOI: 10.1039/C4OB01053A

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Amino acids: fluorescensors for mercury ions

12 Aug 2014

By Richard Kelly.

Arun Ankush Tanpure, a graduate student at IISER Pune, India, writes on a recent OBC article

Many human activities have been responsible for heavy metal poisoning in recent years, Mercury (Hg) poisoning being one of them. Mercury occurs in several forms and even trace concentrations of mercury ions in crops, fish or the human body are enough to produce potentially toxic effects to vital organs. Mercury poisoning can lead to several diseases including Acrodynia (also known as the pink disease), the Hunter-Russell syndrome and the Minamata disease.

Selective detection of mercury, particularly in aqueous media, has been a key area for analytical chemists, since traditional analytical techniques for mercury detection are time consuming, laborious and involve expensive instrumentation. In this work, Korean researcher Keun-Hyeung Lee and co-workers have developed a pair of very sensitive amino acid based fluorescence-ON probes for the exclusive detection of mercury ions in aqueous solution.

The team has combined the fluorescence properties of pyrene and Hg(II) binding ability of tyrosine residues for the design and synthesis of two novel fluorescensors. Both newly-synthesised probes show emission maxima at 386 and 400 nm in the absence of Hg(II) ion. Upon titration with Hg(II) ions, both probes show exponential fluorescence enhancement and display a remarkable red shift (90-100 nm) emission. These probes are also highly selective for mercury ions in the presence of a range of other metal ions and are effective in aqueous solutions.

The team further clarifies the binding mode of these sensors and the coordination of the metal ion. This method can be implemented for rapid and quantitative detection of Hg(II) from various polluted water sources. This work also underscores the unconventional use of an amino acid as a chemosensor.

Ratiometric fluorescence chemosensor based on tyrosine derivatives for monitoring mercury ions in aqueous solutions
Ponnaboina Thirupathi, Ponnaboina Saritha (née Gudellin) and Keun-Hyeung Lee
DOI: 10.1039/C4OB01044B

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Recent HOT Organic & Biomolecular Chemistry articles

24 Jul 2014

By Judy Allen, Publishing Assistant.

Check out the following HOT articles, these have been made free to access for a limited time:

Synthesis and immunological effects of heroin vaccines
Fuying Li, Kejun Cheng, Joshua F. G. Antoline, Malliga R. Iyer, Gary R. Matyas, Oscar B. Torres, Rashmi Jalah, Zoltan Beck, Carl R. Alving, Damon A. Parrish, Jeffrey R. Deschamps, Arthur E. Jacobson and Kenner C. Rice
Org. Biomol. Chem., 2014, Advance Article
DOI: 10.1039/C4OB01053A

Synthesis and immunological effects of heroin vaccines