用2D NMR确定黄酮醇-3-O-L-吡喃鼠李糖(1→2)-L-呋喃阿拉伯糖甙的双糖结构

用2D NMR (¹H-¹H COSY和¹H-¹³C COSY)技术研究了从鹰瓜花中分离到的黄酮醇-3-O-吡喃鼠李糖基呋喃阿拉伯糖甙的双糖结构,明确其双糖为1→2连接.     

Directing/protecting groups mediate highly regioselective glycosylation of monoprotected acceptors

A directing/protecting group designed for regioselective functionalization of partially-protected glucopyrannosides has been successfully used to prepare disaccharides in high yields. Most importantly, it has been demonstrated that highly regioselective and stereoselective glycosylation can be achieved when disarmed donors are employed. This study demonstrates the ability of directing/protecting group to induce regioselective glycosylation of carbohydrates and opens the field to the design of other DPGs for other monosaccharides.     

黄酮醇-3-O-D-木糖(1→2)-L-鼠李糖甙类化合物的NMR谱研究

用2D NMR技术研究了从朝鲜淫羊藿中分离的一个黄酮醇-3-O-D-木糖-鼠李糖甙的结构,确定其双糖为1→2连接,并明确了判断同类黄酮醇-3-O-木糖基(1→2)-鼠李糖甙的简易标准.     

1,3-Dipolar cycloaddition of exo-methylenesugars with nitrone: approach to new amino-C-ketosyl disaccharides

Stereoselective 1,3-dipolar cycloadditions of exo-methylenesugars 1a-c to a sugar nitrone 2 were carried out with refluxing a toluene solution and afforded the corresponding cycloadducts, ketosyl spiro-isoxazolidine disaccharides 3a and 4a-c. Followed by reductive cleavage of the N-O bond of the isoxazolidine ring with the treatment of Zn-AcOH-Ac₂O or with catalytic hydrogenation (Pd(OH)₂/C), the cycloadduct 3a could be readily converted into a novel amino-C-disaccharide possessing a ketose form, providing an access to a novel amino-C-ketosyl disaccharides.     

临床肝素类药物酶解分析二糖组成

肝素是一类结构复杂的高分子糖类,以N-硫酸、6-O硫酸氨基葡萄糖和2-O硫酸艾杜糖醛酸为主要成分组成二糖。常见的肝素注射液是以未分级肝素为原料纯化灭菌制备而来,在临床上使用更为广泛的是将肝素降解得到的低分子片段,低分子肝素保留了肝素糖链基本结构,但是不同制备工艺导致其具有不同的还原及非还原端。本研究以肝素类药物为研究对象,使用肝素裂解酶玉,域及芋将肝素注射液、低分子肝素注射液(达肝素、那屈肝素、依诺肝素)、化学合成的类肝素(磺达肝素)进行酶催化降解产生二糖,结合强阴离子交换色谱( Strong anion exchange high performance liquid chromatography,SAX-HPLC)以及紫外检测器在线分析,使用市售肝素二糖标准品确定各种二糖结构。此外,使用反向离子对色谱和电喷雾质谱联用分析磺达肝素中的甲基二糖以及达肝素和那屈肝素中的脱氨二糖结构,为肝素以及类肝素药物的质量控制提供更为精确的结构信息。     

Syntheses of glucose-containing E5564 analogues and their LPS-antagonistic activities

Lipid A analogues containing a glucose moiety on their non-reducing end were synthesized, and their LPS-antagonistic activities were measured. The inhibitory activities (IC₅₀) on LPS-induced TNFα production of these six compounds, 26, 33, 44β, 52β, 59, and 61, toward human whole blood cells were 0.49, 0.65, 0.51, 0.98, 0.46, and 1.11 nM, respectively. Inhibitory doses (ID₅₀) of compounds 26, 33, 44β, 59, and 61 on TNFα production induced by coinjection of galactosamine and LPS in C3H/HeN mice were measured. The ID₅₀ values of these compounds were 0.45, 0.96, <0.2, 1.08, and <0.2 mg/kg, respectively. Moreover, C3H/HeN mice preinjected with compounds 26, 33, and 44β were protected from lethality induced by coinjection of galactosamine and LPS. Out of eight mice preinjected with 1 mg/kg of compounds 26, 33, and 44β, five, eight and six mice were protected, respectively.     

Synthesis of Analogs of Anacardosidefrom Sem ecarpusAnacardium

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Synthesis of the C‐Glycoside of Methyl α‐d‐Altropyranosyl‐(1→4)‐α‐d‐glucopyranoside

The C‐glycoside of methyl α‐d‐altropyranosyl‐(1→4)‐α‐d‐glucopyranoside 2 was prepared in a convergent fashion, from readily available precursors, 4‐O‐tert‐butyldiphenylsilyl‐1,2‐O‐isopropylidene‐d‐erythro‐S‐phenyl monothiohemiacetal 13 (five steps from D‐ribose) and the known acid, methyl 2,3,6‐tri‐O‐benzyl‐4‐C‐(carboxymethyl)‐4‐deoxy‐α‐d‐glucopyranoside 17 (seven steps from methyl α‐d‐glucopyranoside). The key reactions in the synthesis are the oxocarbenium ion cyclization of thioacetal‐enol ether 19 to a C1 substituted glycal 20, and the stereoselective hydroboration of 20 to the α‐C‐altroside 21.