Pyranoindole and thiopyranoindole. Oxidative cyclization of 3-indolepropanol and 3-indolepropanethiol with N-bromosuccinimide, N-chlorosuccinimide, and singlet oxygen.
作者:TOHRU HINO、HIDETOSHI MIURA、RYOICHI MURATA、MASAKO NAKAGAWA
DOI:10.1248/cpb.26.3695
日期:——
Oxidative cyclization of 3-indolepropanethiol (6) and 3-indolepropanol (9) with N-bromosuccinimide or N-chlorosuccinimide (NCS) gave the corresponding thiopyrano-[2, 3-b] indole (7) and pyrano [2, 3-b] indole (10) in good yields. Reaction of 7 with NCS in carbon tetrachloride gave an unstable chloroindolenine (18) which transformed to a spirooxindole (19) on treatment with ethanolic hydrochloric acid. Reaction of 7 with NBS in carbon tetrachloride gave 7-bromo derivative (20) via the 3-bromoindolenine. Similarly pyranoindole (10) gave a spirooxindole (23) in good yield on treatment with NCS in methylene chloride followed by the addition of ethanolic hydrochloric acid. On the other hand reaction of 9 with two equivalents of NCS gave 23 and dichlorooxindole (24). Dye-sensitized photooxygenation of 3-indolepropanol (9) in benzene gave 4a-hydroxypyrano [2, 3-b] indole instead of 10.
3-吲哚丙硫醇(6)和3-吲哚丙醇(9)与N-溴代琥珀酰亚胺或N-氯代琥珀酰亚胺(NCS)氧化环化,得到相应的吡喃并-[2, 3-b]吲哚(7)和吡喃并[2, 3- b]吲哚(10),收率良好。 7 与 NCS 在四氯化碳中反应,得到不稳定的氯吲哚啉 (18),用盐酸乙醇溶液处理后,其转化为螺吲哚 (19)。 7与NBS在四氯化碳中反应,通过3-溴假吲哚得到7-溴衍生物(20)。类似地,吡喃吲哚(10)用二氯甲烷中的NCS处理,然后添加盐酸乙醇,以良好的收率得到螺吲哚(23)。另一方面,9与两当量的NCS反应得到23和二氯羟吲哚(24)。 3-吲哚丙醇 (9) 在苯中的染料敏化光氧化作用得到 4a-羟基吡喃并[2, 3-b]吲哚,而不是 10。