Synthesis of linear-B saccharopeptides via enzymatic galactosylation of non-natural glucosamide acceptors
摘要:
A series of D- and L-glycopyranuronic acids are coupled to glucosamines to give saccharopeptides. These 'disaccharides'. in which the acetyl moiety of the natural N-acetyl-glucosamine is replaced by various sugar acids, turned out to be surprisingly good substrates for beta (1-4)-galactosyl-transferase and alpha (1-3)-galactosyl-transferase. The enzymes transfer successively two galactose units from the donor UDP-galactose onto these acceptor substrates. despite the far reaching, alterations, regio- and stereospecifically in the expected manner to give linear-B saccharopeptides. (C) 2001 Elsevier Science Ltd. All rights reserved.
General methods for the synthesis of glycopyranosyluronic acid azides
作者:Laiqiang Ying、Jacquelyn Gervay-Hague
DOI:10.1016/s0008-6215(03)00042-9
日期:2003.4
converted to glycosyl iodides and subsequently reacted with an azide source to achieve the stereoselective synthesis of beta-D-glycosyl azides after deacetylation. Low-temperature (4 degrees C) TEMPO oxidation of the monosaccharides provided the corresponding uronic acids, which were purified as the free acids. Oxidation of the lactosyl- and cellobiosyl azides resulted in diacid formation. However, 4',6'-O-benzylidene