New, Concise Route to Indoles Bearing Oxygen or Sulfur Substituent at the 4-Position. Synthesis of (.+-.)- and (S)-(-)-Pindolol and (.+-.)-Chuangxinmycin.
作者:Hiroyuki ISHIBASHI、Susumu AKAMATSU、Hiroko IRIYAMA、Kyoko HANAOKA、Takashi TABATA、Masazumi IKEDA
DOI:10.1248/cpb.42.271
日期:——
A new method for the synthesis of 4-alkoxy- and 4-[alkyl (or aryl)thio]indoles has been developed by using the indolone 3 as a common intermediate. The indolone 3 was prepared from N-(phenylsulfonyl)pyrrole (7) and the α-chlorosulfide 8 in four steps. Heating of a mixture of 3 and an appropriate alcohol in the presence of p-toluenesulfonic acid and cupric chloride afforded the 4-alkoxyindoles 11a-d. The method was applied to the synthesis of (±)-pindolol (19) and (S)-(-)-pindolol (20). Thiols also reacted with 3 in the presence of boron trifluoride to give 4-[aryl (or alkyl)thio]indoles 12, 21a, b, and 22a-d. The (indol-4-ylthio)acetate 22c was employed as a key intermediate for a concise total synthesis of (±)-chuangxinmycin (27).
一种新的合成4-烷氧基和4-[烷基(或芳基)硫代]吲哚的方法已被开发出来,该方法使用吲哚酮3作为共同中间体。吲哚酮3是通过N-(苯磺酰基)吡咯(7)和α-氯磺化物8经过四步反应制备的。在甲苯磺酸和氯化铜的存在下,将3与适当的醇混合并加热,得到了4-烷氧基吲哚11a-d。该方法被应用于合成(±)-吲哚洛尔(19)和(S)-(-)-吲哚洛尔(20)。硫醇在氟硼酸的存在下也能与3反应,生成4-[芳基(或烷基)硫代]吲哚12、21a、b以及22a-d。(吲哚-4-基硫代)乙酸酯22c被用作合成(±)-创新霉素(27)的关键中间体。