Role of Caffeic Acid Sugar Esters in Tree Defense-Repair Processing

咖啡糖酯在损伤反应中起防御修复作用，这是基于观察到毛蕊糖苷在泡桐和马萝卜过氧化物酶的粗酶制备下变成一种聚合物质：这种物质强烈抵抗酸或碱水解。为了在体外和体内证实这一观点，计划制备一种含有^<13>C原子标记的牛油果苷。合成方案从d -葡萄糖开始，共14步：第7步，合成（3′，4′-二乙酰氧基）-乙基2-0-苯甲酰-4,6-0-苄基-3-0-（2,3,4-三-0乙酰- α - l-鼠李糖基）- β -d -葡萄糖吡喃苷，平均产率为80.2%。下一步正在进行中。在侧链的β位置标记有^<13>C原子的咖啡酸从藜芦醇开始，分9步制备。制备了（3′，4′-二羟基苯基）-乙基β -d -葡萄糖作为解释酶氧化毛苷水解行为的模型化合物之一：以（3,4-二羟基苯基）乙酸为起始原料，共6步合成，平均产率为70.2%。

Caffeic sugar esters were postulated to play a role of defense-repair processing in response to wounding, based on the observation that acteoside changed to a polymeric substance, catalyzed by a crude enzyme preparation from paulownia and horse radish peroxidase : This substance was strongly resisted to acid or base hydrolysis. A preparation of acteoside of which the caffeoyl moiety is labelled with ^<13>C atom was planned to confirm this view in vitro and in vivo.A synthetic scheme comprises 14 steps, starting with D-glucose : in the 7th step, (3', 4'-diacetoxyphenyl)-ethyl2-0-benzoyl-4,6-0-benzylidene-3-0- (2,3,4-tri-0 acetyl-alpha-L-rhamnophyranosyl)-beta-D-glucopyranoside was prepared with an average yield of 80.2%. The further step is now inprogress.Caffeic acid labelled at the beta position of the side chain with ^<13>C atom is to be prepared in 9 steps, starting with veratrol.(3', 4'-dihydroxyphenyl)-ethyl beta-D-glucose was prepared as one of the model compounds to interpret the hydrolysis behavior of an enzymatically oxidized acteoside : It was synthesized in the 6 steps with an average yield of 70.2%, starting with (3,4-dihydroxyphenyl) acetic acid.