A research group led by Dr. Kazuaki Ishihara, a professor at Nagoya University, has established a new method of chemically modifying ketones in a way that ensures that optically active cyanohydrins are obtained, enabling efficient production of pharmaceutical precursors at a high yield and with good selectivity.
In the production of pharmaceuticals, it is extremely important to produce molecules that have the right kind of symmetry. Even products that have the same composition, but are mirror images of each other, can have different effects in the body.
Considerable interest has been generated by a recent advance made by scientists at Nagoya University, which was reported online in the journal Angewandte Chemie. Specifically, these researchers managed to modify molecules called ketones by adding new chemical groups in a way that produces more of a single mirror image of the same type of molecule.
This study extends previous work on modifying ketones to produce cyanohydrins, which are useful molecules because they are precursors of carboxylic acids and some amino acids, which are the building blocks of life. The similarity of cyanohydrins and their derivatives to amino acids means that they have important pharmaceutical properties.
However, in previous studies, the modification of ketones to produce cyanohydrins was inefficient, time-consuming, could only produce a small amount of desired product, and was only available for a narrow range of compounds.
These obstacles have now been overcome by an innovative new reaction. “Using a new catalyst, chiral lithium(I) phosphoryl phenoxide, we have been able to add a cyano group with excellent enantioselectivity on ketones using lithium dicyanotrimethylsilicate(IV),” says Dr. Manabu Hatano, an associate professor and the first author. “This reaction had a high yield despite only a weak Lewis acid catalyst being used.”
Previous studies in which efforts were made to produce optically active cyanohydrins encountered difficulties when using ketones rather than aldehydes as the molecules to be cyanosilylated because they are less reactive. This was overcome by the new approach, which was demonstrated by synthesizing a key intermediate for the production of (+)-13-hydroxyisocyclocelabenzine, a pharmaceutical that has antibacterial and antitumor effects.
“Another advantage of our new method is that the reaction time is much shorter, lasting only 2 to 9 hours rather than 1 to 2 days,” according to Katsuya Yamakawa, another member of the research team. “This would be helpful in the pharmaceutical industry when attempting to produce the desired products on a large scale for medical use.”
After the demonstration of this new catalytic system in a large-scale reaction, it is hoped that it can be applied widely for more effective cyanosilylation, enabling cheaper and more accurate production of pharmaceutical products.
The article “Enantioselective Cyanosilylation of Ketones with Lithium(I) Dicyanotrimethylsilicate(IV) Catalyzed by a Chiral Lithium(I) Phosphoryl Phenoxide” was published online in Angewandte Chemie, at doi: 10.1002/anie.201510682
Angewandte Chemie, at doi: 10.1002/anie.201510682
Numbers count in the genetics of moles and melanomas
16.08.2019 | University of Queensland
Working out why plants get sick
16.08.2019 | Institut für Pflanzenbiochemie
Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.
Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...
Researchers at TU Graz are working together with European partners on new possibilities of measuring vehicle emissions.
Today, air pollution is one of the biggest challenges facing European cities. As part of the Horizon 2020 research project CARES (City Air Remote Emission...
Over the next three years, researchers from the Vrije Universiteit Brussel, University of Cambridge, École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI-Paris) and Empa will be working together with the Dutch Polymer manufacturer SupraPolix on the next generation of robots: (soft) robots that ‘feel pain’ and heal themselves. The partners can count on 3 million Euro in support from the European Commission.
Soon robots will not only be found in factories and laboratories, but will be assisting us in our immediate environment. They will help us in the household, to...
Scientists at the University of Leeds have created a new form of gold which is just two atoms thick - the thinnest unsupported gold ever created.
The researchers measured the thickness of the gold to be 0.47 nanometres - that is one million times thinner than a human finger nail. The material is regarded...
An international team of scientists involving the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) in Hamburg has unraveled the light-induced electron-localization dynamics in transition metals at the attosecond timescale. The team investigated for the first time the many-body electron dynamics in transition metals before thermalization sets in. Their work has now appeared in Nature Physics.
The researchers from ETH Zurich (Switzerland), the MPSD (Germany), the Center for Computational Sciences of University of Tsukuba (Japan) and the Center for...
16.08.2019 | Event News
14.08.2019 | Event News
12.08.2019 | Event News
16.08.2019 | Life Sciences
16.08.2019 | Physics and Astronomy
16.08.2019 | Medical Engineering