The nuclei of ordinary hydrogen atoms contain only a single proton. If a neutron is added, the hydrogen becomes deuterium. In principle, molecules that contain deuterium in place of hydrogen atoms are chemically identical. However, there can be significant differences.
Thus “heavy water”, water with molecules that contain deuterium in place of hydrogen, is toxic because it disrupts highly sensitive biochemical processes in the body and leads to metabolic failure. As researchers report in the journal Angewandte Chemie, when the hydrogen atoms of pyridine are replaced with deuterium, it adopts a crystalline form that can only be achieved under high pressure with “normal” pyridine. Perhaps the minimal differences responsible for this type of effect can be implemented to improve the spectrum of properties available to pharmaceutical agents.
Pyridine is a six-membered ring with five carbon atoms and one nitrogen atom. The carbon atoms are each attached to one hydrogen atom. These can be replaced with deuterium. Researchers led by Roland Boese at the University of Duisburg–Essen have discovered that deuterated pyridine crystallizes at about –85 °C with a different crystal structure than that usually adopted by pyridine. In parallel, British researchers working with Simon Parsons determined that non-deuterated pyridine also adopts this structure under high pressure, because it occupies a smaller volume than pyridine’s usual structure.
The replacement of hydrogen by deuterium clearly changes the strength of interactions between individual groups of atoms in neighboring molecules, making other arrangements more energetically favorable. Such interactions between groups of atoms also play an important role in pharmaceuticals, such as when a drug is meant to fit into the binding cavity of an enzyme. Subtle changes can result in significant changes in a drug’s activity. This is why Boese and his team are interested in deuterated pyridine: pyridine is an important starting material for pharmaceuticals, and its basic framework is found in many medications. Boese thinks it likely that deuteration will allow for the development of drug variants that are more specific or have fewer side effects than their conventional precursors.
Author: Roland Boese, Universität Duisburg-Essen (Germany), http://www.structchem.uni-duisburg-essen.de/Dateien/Mitarbeiter/Boese/FR_Boese_en.htm
Title: Isotopic Polymorphism in Pyridine
Angewandte Chemie International Edition 2009, 48, No. 4, 755–757, doi: 10.1002/anie.200803589
Roland Boese | Angewandte Chemie
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences