三氯乙酰亚胺酯法合成紫草素-1′-O-β-D-吡喃葡萄糖苷

Synthesis of shikonin-1′-O-β-D-glucopyranoside by the trichloroacetimide ester method

目的:采用三氯乙酰亚胺酯法合成紫草素-1′-O-β-D-吡喃葡萄糖苷。方法:以β-D-吡喃葡萄糖为起始原料制得糖基供体2,3,4,6-四-O-乙酰基-β-D-吡喃半乳糖酰基2,2,2-三氯乙酰亚胺酯,然后与紫草素反应得1-(1-(5,8-二羟基-1,4-萘醌-2-基)-4-甲基-3-戊烯氧基)-2,3,4,6-四-O-乙酰基-β-吡喃葡萄糖苷,最后在甲醇钠/甲醇体系下醇解脱去乙酰基得到目标化合物,采用核磁共振波谱(NMR)和电喷雾-质谱(ESI-MS)表征其结构。结果:NMR和ESI-MS鉴定目标化合物为紫草素-1′-O-β-D-吡喃葡萄糖苷。三氯乙酰亚胺酯法合成紫草素-1′-O-β-D-吡喃葡萄糖苷总收率为38.9%,HPLC测定纯度为96.7%。结论:本方法合成紫草素-1′-O-β-D-吡喃葡萄糖苷具有高立体选择性和高收率的优点,为紫草素糖基化修饰产物的化学合成提供了参考。

Objective:To synthesize shikonin-1′-O-β-D-glucopyranoside by the trichloroacetimide ester method.Methods:The glycosyl donor 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoyl-2,2,2-trichloroacetyl was prepared fromβ-D-glucopyranose as starting material.The imine ester was then reacted with shikonin to obtain1-(1-(5,8-dihydroxy-1,4-naphthoquinone-2-yl)-4-methyl-3-pentenoxy)-2,3,4,6-tetra-O-acetyl-β-glucopyranoside,and finally alcoholyzed to remove the acetyl group under the sodium methoxide/methanol system to obtain the target compound.The structure of the target compound was elucidated by nuclear magnetic resonance spectroscopy(NMR)and electrospray ionization mass spectrometry(ESI-MS).Results:The target compound was identified as shikonin-1′-O-β-D-glucopyranoside by NMR and ESI-MS.The total yield of shikonin-1′-O-β-D-glucopyranoside synthesized by the trichloroacetimide ester method was 38.9%,and the purity determined by HPLC was 96.7%.Conclusions:The method has the advantages of high stereoselectivity and high yield.It can be used for the synthesis of shikonin-1'-O-β-D-glucopyranoside,and provide a reference for the chemical synthesis of shikonin glycosylation modified products.