(Press-News.org) CHESTNUT HILL, MA (Feb. 14, 2013) – Chemists at Boston College have designed a new class of catalysts triggered by the charge of a single proton, the team reports in the most recent edition of the journal Nature. The simple organic molecules offer a sustainable and highly efficient platform for chemical reactions that produce sets of molecules crucial to advances in medicine and the life sciences.
Unearthing a reliable, truly general, efficient synthesis of single mirror-image isomers has proven elusive. Previous methods suffer from a combination of extreme temperatures, long reaction times, limited scope, low selectivity, the need for rare or precious metals and highly toxic elements.
The new catalysts are small organic molecules derived from the abundant and renewable amino acid valine and can be synthesized in four steps through the use of commercially available and inexpensive materials, according to lead author Amir Hoveyda, the Joseph T. and Patricia Vanderslice Millennium Professor of Chemistry at Boston College.
The catalyst, used in as little as one quarter of a percent, promotes reactions that are complete within two minutes to four hours typically at room temperature, according to the co-authors, which include Boston College Professor of Chemistry Marc Snapper, Senior Research Associate Fredrik Haeffner, post-doctoral researchers Sebastian Torker and Tatiana Pilyugina, and graduate students Erika Vieira and Daniel Silverio.
Products formed consist mainly of a single mirror-image isomer of a large assortment of amines and alcohols, which serve as building blocks for the preparation of molecules capable of advancing new drug therapies relevant to human healthcare.
The electronic activation sparked by the proton and internal hydrogen bonds play a key role in every stage during catalysis of the carbon-carbon bond forming process, according to the researchers. This includes achieving high enantioselectivities – favoring one mirror-image isomer – as well as unprecedented rates of catalyst regeneration and product release.
"A reaction that can be initiated by a minute amount of a readily accessible and inexpensive catalyst to afford valuable organic molecules with high selectivity and which requires only renewable resources, as opposed to precious and rare elements, is extremely important to future advances in medicine and the life sciences," said Hoveyda.
Efficient, selective, cost-effective and sustainable protocols for preparation of organic molecules offer realistic access to significant quantities of a range of biologically active entities. Enantioselective synthesis, preparation of one mirror-image isomer, is crucial in this regard since most important entities in biology and medicine have the property of being handed as well.
"Chemical transformations that are highly selective as well as economical are very important for both discovery and commercial development of new therapeutic and diagnostic agents," said Robert Lees, of the National Institutes of Health's National Institute of General Medical Sciences, which partly funded the work. "The catalysts developed by Dr. Hoveyda represent an impressive advance because they can be used to inexpensively and predictably produce either isomer of a mirror image pair of molecules using mild reaction conditions."
The small-molecule catalysts initiate reactions of readily available boron-containing reagents with easily accessible imines and carbonyls, producing amines and alcohols with a high degree of enantiomeric purity, the team reports. The catalyst's ability to provide access to these prized enantiomerically enriched organic compounds in a manner that is not only efficient and selective but also economical and sustainable for the long term, will be of enormous value to researchers developing anti-cancer agents, therapeutics that reverse multi-drug resistance or anti-viral drugs.
Hoveyda said the discovery will allow chemists to access many valuable organic molecules faster, cheaper and in a sustainable and economic fashion with minimal waste generation and without continuing to depend on diminishing reserves of precious metals.
"The new catalysts have all the key characteristics of a class of molecules that can serve as a blueprint for the invention of many additional important and useful reaction promoters in the future," said Hoveyda.
Sustainable new catalysts fueled by a single proton
Boston College team's new small-molecule catalysts offer a 'green' approach to fine chemical synthesis
ELSE PRESS RELEASES FROM THIS DATE:
'Significant' proportion of HIV positive patients may not be telling NHS staff about their infection
A significant proportion of HIV positive patients may not be disclosing their infection to NHS staff, when turning up for treatment at sexual health clinics, suggests preliminary research published online in the journal Sexually Transmitted Infections. If the findings reflect a national trend, this could have implications for the true prevalence of undiagnosed HIV infection in the population, which is based on the numbers of "undiagnosed" patients at sexual health clinics, say the authors. Currently, it is estimated that around one in four people in the UK who is HIV ...
Over a span of nearly 20 years, California's tobacco control program cost $2.4 billion and reduced health care costs by $134 billion, according to a new study by UC San Francisco. Additionally, the study -- covering the beginning of the program in 1989 to 2008 -- found that the state program helped lead to some 6.8 billion fewer packs of cigarettes being sold that would have been worth $28.5 billion in sales to cigarette companies. The study was designed to calculate the fiscal impact of California's large public health program on smoking prevalence and cigarette consumption. ...
We make choices about pretty much everything, all the time – "Should I go for a walk or grab a coffee?"; "Shall I look at who just came in or continue to watch TV?" – and to do so we need something common as a basis to make the choice. Dr John Fennell and Dr Roland Baddeley of Bristol's School of Experimental Psychology followed a hunch that the common quantity, often referred to simply as reward, was a representation of what could be gained, together with how risky and uncertain it is. They proposed that these dimensions would be a unique feature of all objects and ...
TEMPE, Ariz. – You may want to ramp up your romance this year by sharing a candlelight dinner, a walk on the beach, or even the scent of a perfume, but will that help you find your perfect mate? For one wasp species, it only takes a whiff of his special love potion to know whether he's "Mr. Right." Unlike humans, most insects rely on their sense of smell when looking for a mate. Scientists have found that sex pheromones play an important role in finding a suitable partner of the same species; yet, little is known about the evolution and genetic basis of these alluring ...
New York, NY (February 13, 2013) —For consumers of the typical Western diet—laden with levels of salt detrimental to long-term health—it may be hard to believe that there is such a thing as an innate aversion to very high concentrations of salt. But Charles Zuker, PhD, and colleagues at Columbia University Medical Center have discovered how the tongue detects high concentrations of salt (think seawater levels, not potato chips), the first step in a salt-avoiding behavior common to most mammals. The findings could serve as a springboard for the development of taste ...
CORVALLIS, Ore. – The greatest battle in Earth's history has been going on for hundreds of millions of years, isn't over yet, and until now no one knew it existed, scientists reported today in the journal Nature. In one corner is SAR11, a bacterium that's the most abundant organism in the oceans, survives where most other cells would die and plays a major role in the planet's carbon cycle. It had been theorized that SAR11 was so small and widespread that it must be invulnerable to attack. In the other corner, and so strange looking that scientists previously didn't ...
Penn geologists quantify, characterize sediment carried by Mississippi flood to Louisiana's wetlands
PHILADELPHIA — The spring 2011 flood on the Mississippi was among the largest floods ever, the river swelling over its banks and wreaking destruction in the surrounding areas. But a University of Pennsylvania-led study also shows that the flood reaped environmental benefits — transporting and laying down new sediment in portions of the Delta — that may help maintain the area's wetlands. The study, led by Ph.D. student Nicole Khan of the Department of Earth and Environmental Science, is the first to quantify the amount of sediment transported to wetlands by a flood on ...
COLUMBIA, Mo. – Research shows that married people have better mental and physical health than their unmarried peers and are less likely to develop chronic conditions than their widowed or divorced counterparts. A University of Missouri expert says that people who have happy marriages are more likely to rate their health as better as they age; aging adults whose physical health is declining could especially benefit from improving their marriages. Christine Proulx, an assistant professor in the MU Department of Human Development and Family Studies, examined the long-term ...
The structure of a man's face may indicate his tendency to express racially prejudiced beliefs, according to new research published in Psychological Science, a journal of the Association for Psychological Science. Studies have shown that facial width-to-height ratio (fWHR) is associated with testosterone-related behaviors, which some researchers have linked with aggression. But psychological scientist Eric Hehman of Dartmouth College and colleagues at the University of Delaware speculated that these behaviors may have more to do with social dominance than outright aggression. The ...
New research using combined records of ice measurements from NASA's Ice, Cloud and Land Elevation Satellite (ICESat), the European Space Agency's CryoSat-2 satellite, airborne surveys and ocean-based sensors shows Arctic sea ice volume declined 36 percent in the autumn and 9 percent in the winter over the last decade. The work builds on previous studies using submarine and NASA satellite data and confirms computer model estimates that showed ice volume decreases over the last decade, and builds a foundation for a multi-decadal record of sea ice volume changes. In a report ...