Organic & Biomolecular Chemistry Blog

Victor Pike and colleagues from the National Institute of Mental Health in Bethesda (Maryland, USA) have devised novel and efficient methods to readily access 18F-labelled mGluR5 PET radioligands that are useful for molecular imaging with positron emission tomography (PET).

While iodonium based compounds are considered promising for the preparation of PET radiotracers, very few examples of applications have been realised so far. Now, Pike and colleagues have designed appropriate diaryliodonium tosylates as precursors for introducing fluorine-18 into simple arenes to radiosynthesise standard PET radiotracers. These would otherwise be poorly accessible via traditional aromatic nucleophilic substitution reactions with the [18F]fluoride ion, due to the weak activation of the aryl ring.

The referees and the OBC Editorial office very much enjoyed this excellent paper, and we hope you will too! Read it for FREE for the next 4 weeks.

Syntheses of mGluR5 PET radioligands through the radiofluorination of diaryliodonium tosylates
Sanjay Telu, Joong-Hyun Chun, Fabrice G. Siméon, Shuiyu Lu and Victor W. Pike
Org. Biomol. Chem., 2011, Advance Article
DOI: 10.1039/C1OB05555K, Paper

This hot article from Julio Casado and colleagues at the University of Salamanca provides the first study of the alkylating ability of p-nitrostyrene oxide (pNSO), which is widely used in the pharmaceutical industry as a chiral building block for a variety of drugs.  pNSO is also used as a substrate to study the activity of epoxide hydrolases and in polymer production.

4-(p-nitrobenzyl)pyridine (NBP), a model nucleophile for DNA bases, was used to study the alkylating effects of pNSO.  They found that although pNSO is a strong alkylating agent, it has low efficacy – probably due to the instability of the  NBP-pNSO adduct formed.  A previously unreported pNSO-guanosine adduct was also detected.

For the full details of this interesting study download the article – it’s currently free to access for 4 weeks:

Reactivity of p-nitrostyrene oxide as an alkylating agent. A kinetic approach to biomimetic conditions
Marina González-Pérez, Rafael Gómez-Bombarelli, M. Teresa Pérez-Prior, José A. Manso, Isaac F. Céspedes-Camacho, Emilio Calle and Julio Casado
Org. Biomol. Chem., 2011, Advance Article
DOI: 10.1039/C1OB05909B