Synthesis of the mannosyl erythritol lipid MEL A; confirmation of the configuration of the meso-erythritol moiety
摘要:
The total synthesis of the two possible diastereomers of mannosylerythritol lipid A, a novel biosurfactant from Candida antartica T-34 with promising anti-proliferative properties in several cell lines, is described. By comparison with an authentic sample, the natural material is confirmed as a single diastereomer with the 4-O-(beta -D-mannopyranosyl) D-erythritol configuration. (C) 2002 Elsevier Science Ltd. All rights reserved.
Method of forming glycosidic bonds from thioglycosides using an N,N-dialkylsulfinamide
申请人:——
公开号:US20040019198A1
公开(公告)日:2004-01-29
A method of forming a glycosidic bond utilizing an activated thioglycoside is disclosed. The thioglycoside is activated by an N,N-dialkylsulfinamide and trifluoromethanesulfonic anhydride. The method allows the facile synthesis of disaccharides, oligosacchraides, and polysaccharides in solution or on a polymer support.
The synthesis of isoxazolidinyl nucleosides based on the Vorbruggen nucleosidation of 5-acetoxyisoxazolidines 5 and 9 is reported. The 1,3-dipolar cycloaddition of D- ERYTHRO-nitrone 4 with vinyl acetate proceeded with respectable ANTI-facial (84:16) and ENDO-facial (72:28) diastereoselectivity to give the diastereomeric isoxazolidines 5- 7. The reaction of D- THREO-nitrone 8 with vinyl acetate is