New synthetic approach to C-S-thiotrisaccharides form C-disaccharide enones

CARB 68

Zbigniew J. Witczak, zbigniew.witczak@wilkes.edu1, Joanne Danowski1, Jacqyelyn Dwyer1, Slawomir Jarosz, sljar@icho.edu.pl2, and Elzbieta Kozlowska2. (1) Dept.of Pharmaceutical Sciences, Wilkes University, School of Pharmacy, Wilkes-Barre, PA 18766, (2) Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
In an ongoing program to develop mimetic compounds for certain nonhydrolyzable C-S-oligosaccharides that are derived by the action of glycosidases, we have synthesized C-linked disaccharide analogue 1, specifically protected and functionalized to facilitate stereoselective Michael conjugate addition of reactive 1-thiosugar 2. The high reactivity of conjugate system of 1, under base catalysis (Et3N) is stereoselective producing the S-thiodisaccharide 3 in 89% yields. New C-S-trisaccharide 3, constitute first representative of new family thiotrisaccharides with pentose and hexose functionalized mimetics. The further functionalization by subsequent oximation/reduction/acetylation of the keto function of the conjugate link of 3, produced trisaccharide 4 in 65% overall yields. The final deprotection by cleavage of isopropylidene blocks and deacetylation produce crystalline and water soluble S-trisaccharide derivative 5. The scope and limitation of this novel combination approach of conjugate addition/reduction will be reported in details.

 

General Posters
6:00 PM-8:00 PM, Tuesday, March 27, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Carbohydrate Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007