This project will continue work on the chemistry of organic compounds of sulfur, selenium and tellurium, including development of an environmentally benign nematicide based on garlic oil, study of angiogenesis by compounds related to garlic-derived ajoene, chalcogen-containing molecular wires for use in nanotechnology, completion of the total syntheses of thiarubrine E (an antibiotic from Asteracea plants) and of lentinic acid (novel poly-sulfur compound from shiitake mushrooms), study of sequential one-electron oxidation of 1,5-dichalcogenacyclooctanes, and synthesis of thiacorrannulene and of trifluoromethylselenomethionine (a novel amino acid homologue).
With this award, the Organic and Macromolecular Chemistry Program is supporting the research of Professor Eric Block of the Department of Chemistry at the University at Albany, SUNY. Professor Block's research efforts seek to advance knowledge and develop practical uses of organic compounds of the chalcogen elements (sulfur, selenium and tellurium). The proposed research will contribute to environmentally benign methods for agricultural pest control. Successful development of the proposed methodology will have an impact on agricultural industries. Other projects could lead to the development of new pharmaceuticals as well as new materials for use in nanotechnology.
Consider the senses of sight, hearing and smell. In vision, wavelength translates into color while in audition, frequency translates into pitch. By contrast, the connection between chemical structure and smell is essentially unknown. In previous NSF-sponsored research, the PI and his colleagues discovered how mice signal availability for mating. Thus, fertile male mice excrete in their urine a molecule with a garlic-like aroma called 2-(methylthio)methanethiol, or MTMT for short. Female mice find the smell of MTMT highly attractive and seek out the male mouse to mate. This work was published in Nature in March 2005 (vol. 434, 470-477), and has been highly cited. In following up this work, the PI and his colleagues have now identified the specific mouse olfactory receptor (OR) for MTMT and have discovered that copper ions are required for detection of MTMT by this OR. This work, reported in a forthcoming issue of the Proceedings of the National Academy of Sciences (2012), is the first demonstration of the role of metal ions in mammalian olfaction and has important implications for the field of olfaction and for the detection of volatile odorants in general. Other research supported by this NSF grant involved detection for the first time of a key, elusive intermediate known as a sulfenic acid, formed when garlic is cut or crushed. The sulfenic acid has a lifetime of only a fraction of a second before it self-condenses forming allicin, the key antibiotic flavorant having the smell of fresh garlic. Sulfenic acids are believed to be important antioxidants, which may explain antioxidant properties of garlic and related alliums. The sulfenic acid as well as a variety of other never before detected sulfur compounds were discovered by crushing the tissues of several different Allium species utilizing an instrument known as a DART (Direct Analysis in Real Time) mass spectrometer. This work was published in two papers in the Journal of Agricultural and Food Chemistry (2010, 58, 1121, 4617) as well as in several review articles. Another specialized technique, X-ray fluorescence spectroscopy, was used to determine the cellular location of key sulfur-containing flavor compounds in live onion cells. This work was published in Biochemistry (2009, 48, 6846). The above studies have important applications in the fields of flavor chemistry, crop and pesticide science and agriculture, in addition to basic areas of chemistry, biochemistry and phytochemistry. A detailed discussion of much of the science associated with garlic and related plants, based on 30 years of NSF research support to this investigator, is found in the book, Eric Block, Garlic and Other Alliums: The Lore and the Science, Royal Society of Chemistry, Cambridge, 2010. The book received a very favorable review in the New York Times (www.nytimes.com/2010/06/09/dining/09curious.html) and has been featured on NPR’s Science Friday (7/2/2010), on Wisconsin Public Radio’s Here on Earth (7/9/2010), as well as in various public lectures and book signings in the U.S. and Europe. www.npr.org/templates/story/story.php?storyId=128268496 Based on Eric Block’s continuing NSF-sponsored research in agriculturally related areas, he has been selected by the U.S. Department of Agriculture as the Sterling B. Hendricks Memorial Lecture Awardee for 2012, with the address to be presented in Philadelphia in August 2012.
