Hemisynthesis of anthocyano-ellagitannin hybrids.

15/12/2003 · DNA Topoisomerase Inhibitor Acutissimin A and ..
Photo provided by Flickr

Ellagitannin Chemistry - Chemical Reviews (ACS …

Ken Feldman was born and raised in Miami Beach, FL. In 1978, he obtained his B.S. degree in chemistry while exploring the ipso nitration reaction of substituted aromatics in Philip Myhre's lab at Harvey Mudd College. His Ph.D. work at Stanford University with E. E. van Tamelen focused on biomimetic syntheses of marine and terrestrial natural products. After a year-long stint as a post-doctoral fellow at Dupont, he joined the faculty of the chemistry department at Penn State as an assistant professor in 1984. His current research interests include the chemistry and biology of the ellagitannin class of secondary plant metabolites, and the rational synthesis of multidimensional periodic organic networks that may exhibit “zeolitic” properties.

15/12/2003 · DNA Topoisomerase Inhibitor Acutissimin A and Other ..
Photo provided by Flickr

and other flavano-ellagitannins are formed ..

FEATURE ARTICLE 3880 Synthesis of Biaryl-Containing Medium-Ring Systems by Organocuprate Oxi dation: Applications in the Total Synthesis of Ellagitannin Natural Products

All five ellagitannin derivatives ..
Photo provided by Flickr

An extraction procedure and an analytical method have been developed to detect and quantify for the first time a series of ellagitannin derivatives formed in wine during aging in oak barrels. The method involves a preliminary purification step on XAD7 HP resin followed by a second purification step on TSK 40 HW gel. The resulting extract is analyzed for compound identification and quantitative determination by high-performance liquid chromatography−electrospray ionization−mass spectrometry in single ion recording mode. Reference compounds, which are accessible through hemisynthesis from the oak -glycosidic ellagitannin vescalagin, were used to build calibration curves, and chlorogenic acid was selected as an internal standard. This method enabled us to estimate the content of four flavano-ellagitannins and that of another newly identified wine polyphenol, β-1--ethylvescalagin, in a Bordeaux red wine aged for 18 months in oak barrels. All five ellagitannin derivatives are derived from the nucleophilic substitution reaction of vescalagin with the grape flavan-3-ols catechin and epicatechin or ethanol.

15/05/2013 · Hydrolyzable Tannins: Gallotannins and Ellagitannins
Photo provided by Flickr