Integrating ReSET with Glycosyl Iodide Glycosylation in Step-Economy Syntheses of Tumor-Associated Carbohydrate Antigens and Immunogenic Glycolipids
作者:Hsiao-Wu Hsieh、Matthew W. Schombs、Jacquelyn Gervay-Hague
DOI:10.1021/jo402736g
日期:2014.2.21
Carbohydrates mediate a wide range of biological processes, and understanding these events and how they might be influenced is a complex undertaking that requires access to pure glycoconjugates. The isolation of sufficient quantities of carbohydrates and glycolipids from biological samples remains a significant challenge that has redirected efforts toward chemical synthesis. However, progress toward complex glycoconjugate total synthesis has been slowed by the need for multiple protection and deprotection steps owing to the large number of similarly reactive hydroxyls in carbohydrates. Two methodologies, regioselective silyl exchange technology (ReSET) and glycosyl iodide glycosylation have now been integrated to streamline the synthesis of the globo series trisaccharides (globotriaose and isoglobotriaose) and alpha-lactosylceramide (alpha-LacCer). These glycoconjugates include tumor-associated carbohydrate antigens (TACAs) and immunostimulatory glycolipids that hold promise as immunotherapeutics. Beyond the utility of the step-economy syntheses afforded by this synthetic platform, the studies also reveal a unique electronic interplay between acetate and silyl ether protecting groups. Incorporation of acetates proximal to silyl ethers attenuates their reactivity while reducing undesirable side reactions. This phenomenon can be used to fine-tune the reactivity of silylated/acetylated sugar building blocks.
New Disaccharide-Based Ether Lipids as SK3 Ion Channel Inhibitors
作者:Wilfried Berthe、Charlotte M. Sevrain、Aurélie Chantôme、Ana Maria Bouchet、Maxime Gueguinou、Yann Fourbon、Marie Potier-Cartereau、Jean-Pierre Haelters、Hélène Couthon-Gourvès、Christophe Vandier、Paul-Alain Jaffrès
DOI:10.1002/cmdc.201600147
日期:2016.7.19
The SK3 potassium channel is involved in the development of bone metastasis and in the settlement of cancer cells in Ca2+‐rich environments. Ohmline, which is a lactose‐based glycero‐etherlipid, is a lead compound that decreases SK3channel activity and consequently limits the migration of SK3‐expressing cells. Herein we report the synthesis of three new ohmline analogues in which the connection of
在富含Ca 2+的环境中,SK3钾通道参与了骨转移的发展和癌细胞的沉降。Ohmline是一种基于乳糖的甘油醚脂质,是降低SK3通道活性并因此限制了表达SK3的细胞迁移的先导化合物。在本文中,我们报道了三种新的欧姆线类似物的合成,其中研究了二糖部分的连接(1→6对1→4)和糖基键的立体化学。化合物2 [3-(十六烷氧基)-2-甲氧基丙基-6- ö -α- d吡喃葡萄糖基-β- d-galactopyranoside],其具有α-D-吡喃葡糖基(1→6)-β-D-吡喃半乳糖基部分,被发现以减少SK3电流幅度(70%抑制在10μ米),位移SK3蛋白小窝外,降低组成型的Ca 2 +进入(在300 n m处抑制50%)和SK3依赖性细胞迁移(在300 n m处抑制30%),其水平接近于基准化合物欧姆线。降低SK3通道(但不降低SK2通道)活性的化合物2是减少癌细胞迁移和预防骨转移的新药候选物。
Regioselective Silyl/Acetate Exchange of Disaccharides Yields Advanced Glycosyl Donor and Acceptor Precursors
作者:Hsiao-Wu Hsieh、Matthew W. Schombs、Mark A. Witschi、Jacquelyn Gervay-Hague
DOI:10.1021/jo4013805
日期:2013.10.4
exchange of silicon for acetate protecting groups occurs. Acid concentration, thermal conditions, and microwave assistance mediate the silyl/acetate exchange reaction. Regiocontrol is achieved by limiting the equivalents of aceticacid, and microwave irradiation hastens the process. We coined the term Regioselective Silyl Exchange Technology (ReSET) to describe this process, which essentially sets the