ChemWeb Newsletter

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This week, Argonne National Laboratory picks up three awards for innovative science, while elsewhere in Illinois, chemists have developed a novel catalytic approach that side-steps functional group modifications to streamline organic syntheses. The Alchemist also discovers that a serendipitous finding leads to a bright spot in observing electron transfer in single molecules under the scanning tunneling microscope. In Africa, extracts of the leaves of the so-called hemorrhage plant could provide medical science with a new approach to faster, cleaner wound healing. While mixed messages emerge regarding the safety of bisphenol A. Finally this week, upping the glucosinolate content of brassica crops might not only help cabbage, broccoli, and cauliflower ward off pests and so save on pesticide use, but could also boost the cancer-fighting powers of these foods for people who eat them.

Passive millimeter-wave spectroscopy developed by scientists working at Argonne National Laboratory is one of the top 100 developments in science and technology for 2006 as judged by R&D Magazine in its annual awards. The developers are Argonne Senior Electrical Engineer Sami Gopalsami, Electrical Engineer Sasan Bakhtiari, Department Manager Paul Raptis, Special Term Appointee Thomas W. Elmer and Senior Technician Ronald N. Lanham. This technology could be key in combating chemical weapons attacks by providing an early warning system that detects and identifies distant gas plumes based on their millimeter-wave emissions. Two additional ANL projects, Access Grid and ultra-high resolution mammography, were also cited in the Top 100.

University of Illinois chemists hope to meet the efficiency challenge in organic chemistry by exploiting a newly developed class of carbon-hydrogen catalyst. Christina White and her colleagues are creating a new chemical toolbox of highly selective and reactive catalysts that are tolerant of other functionality. "By offering fewer steps, fewer functional group manipulations and higher yields, this toolbox will change the way chemists make molecules," White claims. A palladium/sulfoxide catalyst provides the team with a selective method for directly inserting nitrogen functionality into relatively inert C-H bonds without having to manipulate functional groups. The team has reported streamlined syntheses of various compounds, including a peptidase inhibitor drug candidate, a nucleotide-sugar L-galactose, and the chemotherapeutic reagent acosamine. She and her colleagues are currently applying the technology to synthesizing the antibiotic erythromycin A.

Electron transfer reactions have been observed at the single molecule level for the first time on an electrode surface. The research could speed up developments in a wide range of areas including molecular electronics, electrochemistry, catalysis, information storage, and solar energy conversion. Eric Borguet of Temple University points out that chemistry is fundamentally about the transfer of electrons from one atom to another, so understanding how this happens is critical to understanding and exploit all kinds of reactions. The Temple researchers used scanning tunneling microscopy to study the transfer of electrons in a porphyrin film on a metal electrode. Electron transfer from a single porphyrin molecule makes the porphyrin appear darker in the STM while in the reduced state the molecule is bright.

A plant from African folkore has been tested successfully for its ability to stop bleeding. Aspilia africana is widespread across Africa and used traditionally to stop bleeding from wounds, clean sores, treat rheumatic pains, as well as bee and scorpion stings. Writing in the journal, BMC Complementary and Alternative Medicine, researchers from the University of Nigeria and the University of New South Wales, Australia, explain how extracts of the plant contain demonstrable bleeding inhibitors as well as being able to slow the growth of microbes, including Pseudomonas fluorescens and Staphylococcus aureus.

A clutch of papers raising concerns about the health effects and environmental impact of bisphenol A are discussed this week in the American Chemical Society magazine C&EN. The magazine reports that low levels of human exposure to bisphenol A (BPA), a compound widely used in the manufacture of polycarbonate and epoxy resins, could have adverse health affects. Four toxicology studies demonstrate health effects as diverse as increased rates of breast and prostate cancer, reproductive abnormalities, obesity, and insulin-dependent diabetes. The magazines also reports that, despite growing evidence of toxic effects in laboratory animals, manufacturers of BPA say the product is safe. In stark contrast with the papers highlighted in the article, C&EN also reports that the European Food Safety Authority stated recently that there are no adverse effects of BPA.

Masami Yokota Hirai and Kazuki Saito from RIKENÕs Plant Science Center in Yokohama have identified the genes controlling glucosinolate production in cabbage, broccoli and cauliflower. These compounds are natural pesticides but are also known to have potential antioxidant and anti-carcinogenic properties. The team combined data from two "omics" techniques - transcriptomics and metabolomics - to define the molecular biology of the glucosinolate biosynthetic pathway. The team suggests that breeding or engineering brasssica to overexpress glucosinolate production might reduce pesticide requirements as well as improve the nutritional value of these vegetables.