Iodine-Catalyzed Oxidative Cross-Coupling of Indoles and Azoles: Regioselective Synthesis of <i>N</i>‑Linked 2‑(Azol-1-yl)indole Derivatives

A highly efficient iodine-catalyzed regioselective oxidative cross-coupling of an indole C–H bond and azole N–H bond is described. This metal-free reaction can be easily carried out at room temperature under mild and environmentally friendly conditions and provides a series of <i>N</i>-linked 2-(azol-1-yl)­indole derivatives in moderate to excellence yields

Synthesis of 8-(1,2,3-triazol-1-yl)-7-deazapurine nucleosides by azide–alkyne click reactions and direct C H bond functionalization

Treatment of toyocamycin or sangivamycin with 1,3-dibromo-5,5-dimethylhydantoin in MeOH (r.t./30 min) gave 8-bromotoyocamycin and 8-bromosangivamycin in good yields. Nucleophilic aromatic substitution of 8-bromotoyocamycin with sodium azide provided novel 8-azidotoyocamycin. Strain promoted click reactions of the latter with cyclooctynes resulted in the formation of the 1,2,3-triazole products. Iodine-mediated direct C8-H bond functionalization of tubercidin with benzotriazoles in the presence of tert-butyl hydroperoxide gave the corresponding 8-benzotriazolyltubercidin derivatives. The 8-(1,2,3-triazol-1-yl)-7-deazapurine derivatives showed moderate quantum yields and a large Stokes shifts of ~ 100 nm