Synthesis of Furan and Thiophene Analogs of Duocarmycin SA.
作者:Hideaki MURATAKE、Kazuaki OKABE、Michiko TAKAHASHI、Miyuki TONEGAWA、Mtsutaka NATSUME
DOI:10.1248/cpb.45.799
日期:——
Total synthesis of furan and thiophene analogs 6 and 7 of duocarmycin SA was achieved in racemic forms, starting from methyl 4, 5-dibromo-2-furan- and thiophenecarboxylates (15a and 15b). Lithio derivatives 12a (a series : X=O) and 12b (b serie : X=S) were reacted with the aldehyde 22 for preparation of 25a and 25b, and successive synthetic operations, including Heck reaction of 25a and 25b to obtain 26a+27a and 26b+27b, and B ring aromatization, 28a and 28n→31a and 31b, based on our previous total synthesis of duocarmycin SA, afforded 36a and 36b. Treatment of 36a and 36b with potassium carbonate in methanol directly afforded cyclopropapyrroloindole derivatives 38a and 38b, whose condensation with the 5, 6, 7-trimethoxy-2-indolecarbonyl unit completed the synthesis of (±)-6 and (±)-7.
实现了二重霉素 SA 的呋喃和噻吩类似物 6 和 7 的全合成,起始于甲基 4, 5-二溴-2-呋喃和噻吩羧酸酯(15a 和 15b)的外消旋形式。锂衍生物 12a(一系列:X=O)和 12b(二系列:X=S)与醛 22 反应,制备了 25a 和 25b,随后的合成操作包括对 25a 和 25b 的 Heck 反应,得到 26a+27a 和 26b+27b,以及 B 环芳香化 28a 和 28n→31a 和 31b,基于我们之前的二重霉素 SA 全合成,得到 36a 和 36b。用碳酸钾在甲醇中处理 36a 和 36b 直接得到环丙烯基吡咯并吲哚衍生物 38a 和 38b,它们与 5, 6, 7-三甲氧基-2-吲哚羧酰基单元的缩合完成了 (±)-6 和 (±)-7 的合成。