An efficient route to prepare L-glucose and L-galactose is described. The L-sugars are achieved by using the strategy of switching the functional groups at C1 and C5 of D-glucose and D-mannose. The oxidation and reduction of the silyl enol ether at C1 and the lead（IV） tetraacetate mediated oxidative decarboxylation at C5 are the key steps. L-Glucose and L-galactose are prepared in a convenient and inexpensive way.
Tian-Yu XiaYang-Bing LiZhao-Jun YinXiang-Bao MengShu-Chun LiZhong-Jun Li
We utilized the glycosyl acceptor tagging method with ionic liquid support for synthesis of the core segment of Clostridium botulinum C2 toxin ligand through a divergent synthetic strategy without chromatographic purification.The total yield was 57.1% and the reaction was completed in 10 h.The efficient ionic liquid supported glycosylation and purification procedure was applied for the synthesis of branched glucosamine-containing oligosaccharides for the first time,which expanded the scope of ionic liquid supported synthesis of biologically important oligosaccharides.
Ze-Shen GaoSheng SunWei LiQing MaQing LiZhong-Jun Li
A new carrier containing three hydrophobic octadecyls was employed to improve the yield and purity of the synthesized oligosaccharides, and the applicability of hydrophobic carrier for HASP （hydrophobically assisted switching phase） was also explored. High performance liquid chromatography （HPLC） was used to analyze the purity of oligosaccharides and improve the elution efficiency. Elution system was optimized and replaced by isopropyl alcohol and water, in which the excess donor and other impurities had a better solubility than that in methanol.
Yunhe WangShuai MengTingting YueShuchun LiZhongjun Li
Three new iminosugar-containing KRN7000 （also referred to as α-GalCer） analogues were designed and syn- thesized. In the design, the galactose moiety of KRN7000 was replaced by iminosugars and the iminosugar struc- tures were connected with ceramide in different manners with a C-glycosidic bond instead of the O-glycosidic bond. To our knowledge, this is the first report in which iminosugars are incorporated in KRN7000 structure modifica- tions. The synthetic compounds were evaluated for their ability to stimulate cytokine release. The results may benefit better understanding of structure-activity relationships and facilitate future design of more KRNT000 derivatives.
By analyzing the key steps that restricted the industrial synthesis of salidroside, selective protection of tyrosol with different acylation reagents was adopted. The strategy facilitated the crystallization of intermediates, which allowed the scalable synthesis of salidroside. It included a reaction of penta-O-acetyl-β-D-glucose with acyl protected tyrosol in the presence of Lewis acid catalyst（ZnCl2）, followed by deacylation under basic condition（NaOMe/MeOH） to give the salidroside. The total yield of this three-step reaction was 47%. Final product and intermediates were purified by recrystallization, which significantly reduced the cost and made the large scale synthesis feasible.
