Mild and Selective Ru-Catalyzed Formylation and Fe-Catalyzed Acylation of Free (N-H) Indoles Using Anilines as the Carbonyl Source was written by Wu, Wenliang;Su, Weiping. And the article was included in Journal of the American Chemical Society in 2011.Electric Literature of C9H6ClNO This article mentions the following:
Indoles undergo regioselective formylation and acylation reactions with N-methylaniline or N-benzylanilines in the presence of either ruthenium(III) or iron(II) chlorides using tert-Bu hydroperoxide as the oxidant to give 3-formyl or 3-benzoylindoles in 34-86% yields. The processes are operationally simple and compatible with a variety of functional groups. Reaction of indole with N-(13C-methyl)aniline yields 3-(13C-formyl)indole in 70% yield, unambiguously establishing that the carbonyl carbon in the formylation products originates from the Me group of N-Me aniline. In the experiment, the researchers used many compounds, for example, 5-Chloroindole-3-carboxaldehyde (cas: 827-01-0Electric Literature of C9H6ClNO).
5-Chloroindole-3-carboxaldehyde (cas: 827-01-0) belongs to indole derivatives. Indole could be stereoselectively alkylated with chiral cyclopentyl sulfone reagent. Due to this activity, the indole ring system has become an important component or intermediate in the synthesis of heterocycles.Electric Literature of C9H6ClNO
Referemce:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles