RESEARCH GROUPS

Head of Department

Dr. John StephensPhoto of John Stephens research group

Synthetic Organic and Medicinal Chemistry

 

Dr. John Stephens
Phone: + 353 (0)1 7086942
Email: john.stephens@nuim.ie
Fax: + 353 (0)1 7083815
Room: 2.66

 

 

Research Interests

The Stephens group carries out research in synthetic organic chemistry with a focus on medicinal chemistry and asymmetric synthesis.

Medicinal chemistry: Medicinal chemistry involves the design, synthesis and development of new pharmaceutical drugs that are suitable for therapeutic use. Dr Stephens has a particular interest in diabetes, neurological disorders and microbial infections and is currently investigating new routes to novel chemical therapies. These projects are interdisciplinary and involve collaborative work with Prof Findlay, Dr Kinsella and Dr Kavanagh in the biology department at NUI Maynooth. Please watch the video below for further information on this research.

 


Asymmetric synthesis: Dr Stephens’ interest in asymmetric synthesis lies in the efficient control of selectivity (enantio-, diastereo, regio-, and chemo-) in bond making reactions, particularly C-C bond making processes. The demand for new and economical asymmetric reactions is being driven by the pharmaceutical industry due to the chiral nature of many pharmaceutical products. Dr Stephens collaborates with Prof Alexakis, University of Geneva, on these projects.

Fluorescent probes: Dr Stephens is also interested in the design, synthesis and application of novel fluorophores. Dr Stephens employs cycloaddition chemistry in the generation of new fluorescent heterocycles and investigates their photophysics in collaboration with Dr Alan Ryder at NUI Galway.

Biosynthetic pathways: Dr Stephens is also involved in the investigation and elucidation of biosynthetic pathways in microorganism and carries out collaborative research with Prof Sean Doyle, biology department at NUI Maynooth, into the biosynthetic pathways of Aspergillus fumigatus.

 

Research Collaborators:

 

Prof Alexandre Alexakis (University of Geneva): Organocatalytic asymmetric reactions.

 

Dr Gerard McGlacken (University College Cork): Asymmetric catalytic transformations.


Dr Alan Ryder (NUI Galway): Photophysics and fluorescent studies of new organic fluorophores.


Prof John Findlay (Biology, NUIM): Development of new therapeutics for type II diabetes.


Dr Gemma Kinsella (Biology, NUIM): Development of new therapeutics for type II diabetes.


Prof Sean Doyle (Biology, NUIM): Investigating the biosynthetic pathways of Aspergillus fumigatus.


Dr Kevin Kavanagh (Biology, NUIM): The design, synthesis and evaluation of novel antimicrobial agents.


Dr John McGinley (Chemistry, NUIM): The design, synthesis and evaluation of novel antimicrobial agents.


Dr Malachy McCann (Chemistry, NUIM): The design, synthesis and evaluation of novel antimicrobial agents.

 

 

Selected Publications

 

Theoretical characterization of pentazole anion with metal counter ions. Calculated and experimental N-15 shifts of aryldiazonium, -azide and -pentazole systems. L.A. Burke, R.N. Butler, J.C. Stephens, J. Chem. Soc. Perkin 2, 2001, 1679.

 

First generation of pentazole (HN5, pentazolic acid), the final azole, and a zinc pentazolate salt in solution: A new N-dearylation of 1-(p-methoxyphenyl) pyrazoles, a 2-(p-methoxyphenyl) tetrazole and application of the methodology to 1-(p-methoxyphenyl) pentazole. R.N. Butler, J.C. Stephens, L.A. Burke, Chem. Commun., 2003, 1016.

 

First Reversible Protonation of a 1-Arylpentazole. R.N. Butler, J.C. Stephens, J.M. Hanniffy, Tetrahedron Lett., 2004, 45, 1977.

 

Sulfonic Acid and Libraries Attained Through Opening of 2-Sulfobenzoic Acid Anhydride. R.I. Robinson, J.C. Stephens, S.M. Worden, A.J. Blake, C. Wilson, S. Woodward, Eur. J. Org. Chem., 2004, 4596.

 

Investigations into the Utility of High-Surface Area Silica Pellets as Potential Solid-Phase Synthesis Supports. R.S. Timofte, J.J. Titman, L. Shao, J.C. Stephens, S. Woodward, Tetrahedron, 2005, 61, 51-59.

 

New Reactive Fluorophores in the 1,2,3-Triazine Series. R. N. Butler, A. M. Fahy, A. Fox, J. C. Stephens, P. McArdle, D. Cunningham, A. G. Ryder, Tetrahedron Lett., 2006, 47, 1721.

 

One-Pot Synthesis of Fluorescent 2,5-Dihydro-1,2,3-triazine Derivatives from a Cascade Rearrangement Sequence in the Reactions of 1,2,3-Triazolium-1-aminide 1,3-Dipole with Propiolate Esters. R. N. Butler, A. M. Fahy, A. Fox, J. C. Stephens, P. McArdle, D. Cunningham, A. G. Ryder, J. Org. Chem., 2006, 71, 4596

 

Demonstration of promoted zinc Schlenk equilibria, their equilibrium values and derived reactivity, A. J. Blake, J. Shannon, J. C. Stephens, S. Woodward, Chem. Eur. J., 2007, 13, 2462.

 

A Ceric Ammonium Nitrate (CAN) N-Dearylation of N-p-Anisylazoles Applied to Pyrazole, Triazole, Tetrazole and Pentazole Rings: Release of Parent Azoles. Generation of Unstable Pentazole, HN5/N5-, in Solution, R. N. Butler, J. M. Hanniffy, J. C. Stephens, L. A. Burke, J. Org. Chem., 2008, 73, 1354.

 

Self-Protection against Gliotoxin- A Component of the Gliotoxin Biosynthetic Cluster, GliT, Completely Protects Aspergillus fumigatus Against Exogenous Gliotoxin. M. Schrettl, S. Carberry, K. Kavanagh, H. Haas, G. Jones, J. O’Brien, A. Nolan, J. Stephens, O. Fenelon, S. Doyle. PLoS Pathogens, 2010, 6, e1000952.

 

The Role of Glutathione S-Transferase GliG in Gliotoxin Biosynthesis in Aspergillus fumigates, C. Davis, Stephen Carberry, M. Schrettl, I. Singh, J. C. Stephens, S. M. Barry, K. Kavanagh, G. L. Challis, D. Brougham and S. Doyle, Chemistry & Biology 2011, 18, 542.

 

Asymmetric Organocatalytic 1,6-Conjugate Addition of Aldehydes to Dienic Sulfones, J. J. Murphy, A. Quintard, P. McArdle, A. Alexakis and J. C. Stephens, Angew. Chem. Int. Ed. 2011, 50, 5095.

 

Organocatalytic enantioselective Michael addition of β-diketones to β-nitrostyrene: The first Michael addition of dipivaloylmethane to an activated olefin, D. P. Gavin and J. C. Stephens, Arkivoc 2011, (ix), 407.

 


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