Chemists devise better way to prepare workhorse molecules

Jun 09, 2011 by Terry Devitt

In chemistry, so-called aromatic molecules compose a large and versatile family of chemical compounds that are the stuff of pharmaceuticals, electronic materials and consumer products ranging from sunscreen to plastic soda bottles.

Writing in the current online issue (June 9) of the journal Science, a team led by University of Wisconsin-Madison chemistry Professor Shannon Stahl reports a new, environmentally friendly way to make substituted aromatic molecules that can be customized for different industrial needs.

As college chemistry students know, aromatic molecules have a special stability conferred by a ring of six with alternating single and . "The ultimate utility of these molecules depends on the chemical groups attached at the corners of this hexagonal platform," explains Stahl. "Interest in preparing substituted aromatic molecules traces back to the dawn of ."

In fact, the 2010 Nobel Prize in Chemistry was awarded for catalytic chemical reactions that allow the introduction of specific groups to the periphery of aromatic molecules. These methods, and older traditional methods, rely on modifying an existing aromatic molecule, Stahl explains. But the stability of aromatic molecules can make such approaches difficult, and existing methods also have many limitations in the types and patterns of chemical groups that can be installed.

The method devised by Stahl and Wisconsin colleagues Yusuke Izawa and Doris Pun owes its success to the discovery of a new palladium catalyst. The catalyst gives chemists a way to peel off hydrogen from cyclic molecules to form aromatic products with the desired substitution patterns already in place. The hydrogen removed by the palladium catalyst is combined with oxygen, and water is formed as the only .

The Wisconsin team demonstrated the utility and efficiency of the new process on phenols, aromatic compounds that are produced on a large scale as precursors to many kinds of industrial materials and pharmaceutical agents. While the new catalytic method can be used to make a broad spectrum of aromatic molecules of interest to science and industry, the new work will be of most immediate practical use to drug companies, according to Stahl. For example, an anticancer agent that was difficult to make using previously known methods was efficiently produced using the strategy devised by the team.

Stahl notes that the work published today in Science will require more development before it is suitable for large-scale industrial production, but he emphasizes that concepts introduced by the new work will have broad utility. "Many new catalysts, reaction conditions and target molecules can be envisioned. Overall, this route to substituted aromatic molecules has a lot of potential," he says.

Explore further: Simulations for better transparent oxide layers

Related Stories

A new way to prepare fluorinated pharmaceuticals

Aug 13, 2009

(PhysOrg.com) -- A team of MIT chemists has devised a new way to add fluorine to a variety of compounds used in many drugs and agricultural chemicals, an advance that could offer more flexibility and potential cost-savings ...

Coal Liquefaction

Jan 09, 2006

The tightening of worldwide oil reserves is causing the price of oil to escalate — and makes coal, which is much more abundantly available, an interesting starting material for liquid fuels and chemical raw materials. Researchers ...

Molecules Dress for Success

Sep 25, 2006

An enormous challenge to science is the generation of two individual molecules that are not chemically bound to each other but are mechanically wedged together to form a tight link. A team of British and American researchers ...

Recommended for you

Simulations for better transparent oxide layers

18 hours ago

Touchscreens and solar cells rely on special oxide layers. However, errors in the layers' atomic structure impair not only their transparency, but also their conductivity. Using atomic models, Fraunhofer ...

Team pioneers strategy for creating new materials

Aug 29, 2014

Making something new is never easy. Scientists constantly theorize about new materials, but when the material is manufactured it doesn't always work as expected. To create a new strategy for designing materials, ...

Plug n' Play protein crystals

Aug 29, 2014

Almost a hundred years ago in 1929 Linus Pauling presented the famous Pauling's Rules to describe the principles governing the structure of complex ionic crystals. These rules essentially describe how the ...

User comments : 0