Yoshikawa M, Shimada H, Yagi N, Murakami N, Shimoda H, Yamahara J, Matsuda H
Kyoto Pharmaceutical University, Japan.
Chem Pharm Bull (Tokyo). 1996 Oct;44(10):1890-8. doi: 10.1248/cpb.44.1890.
Lactonization reaction of 2-carboxystilbene mediated by copper(II) chloride proceeded regiospecifically to give the five-membered lactone, while the bromolactonizations using N-bromosuccinimide and anodic oxidation were found to furnish the six-membered lactone. Using these regiospecific lactonization reactions as a key step, antiallergic and antimicrobial isocoumarins and the benzylidenephthalides thunberginols A and F and their 3'-deoxyanalogs were synthesized from phyllodulcin and hydrangenol. Two phthalides called hydramacrophyllols A and B were isolated from Hydrangeae Dulcis Folium and their stereostructures were determined on the basis of physicochemical and chemical evidence, which included the syntheses of hydramacrophyllols A and B from hydrangenol by the application of the lactonization method using copper(II) chloride. In addition, hydramacrophyllols A and B were found to exhibit an inhibitory effect on the histamine release from rat peritoneal exudate cells induced by antigen-antibody reaction.
由氯化铜（II）介导的2-羧基芪的内酯化反应区域特异性地进行，生成五元内酯，而使用N-溴代琥珀酰亚胺的溴内酯化反应和阳极氧化反应则生成六元内酯。以这些区域特异性内酯化反应为关键步骤，从根皮苷和氢化根皮素合成了抗过敏和抗菌的异香豆素以及亚苄基苯酞类化合物桑皮素A和F及其3'-脱氧类似物。从甜茶中分离出两种名为水合大叶素A和B的苯酞类化合物，并根据物理化学和化学证据确定了它们的立体结构，其中包括通过应用氯化铜（II）的内酯化方法从氢化根皮素合成水合大叶素A和B。此外，发现水合大叶素A和B对抗原-抗体反应诱导的大鼠腹腔渗出细胞组胺释放具有抑制作用。
