Selectivity, Speciation, and Substrate Control in the Gold-Catalyzed Coupling of Indoles and Alkynes was written by Epton, Ryan G.;Unsworth, William P.;Lynam, Jason M.. And the article was included in Organometallics in 2022.Safety of 6-Nitro-1H-indole This article mentions the following:
A convenient and mild protocol for the Au-catalyzed intermol. coupling of substituted indoles with carbonyl-functionalized alkynes to give vinyl indoles is reported. This reaction affords 3-substituted indoles in high yield, and in contrast to the analogous reactions with simple alkynes which give bisindolemethanes, only a single indole is added to the alkyne. The protocol is robust and tolerates substitution at a range of positions of the indole and the use of ester-, amide- and ketone-substituted alkynes. The use of 3-substituted indoles as substrates results in the introduction of the vinyl substituent at the 2-position of the ring. A combined exptl. and computational mechanistic study revealed that the Au catalyst has a greater affinity to the indole than the alkyne, despite the C-C bond formation step proceeding through an η2(π)-alkyne complex, which helps to explain the Stark differences between the intra- and intermol. variants of the reaction. Also the addition of a 2nd indole to the carbonyl-containing vinyl indole products is both kinetically and thermodynamically less favored than in the case of more simple alkynes, providing an explanation for the observed selectivity. Finally, a highly unusual Au-promoted alkyne dimerization reaction to form a substituted Au pyrylium salt was identified and studied. In the experiment, the researchers used many compounds, for example, 6-Nitro-1H-indole (cas: 4769-96-4Safety of 6-Nitro-1H-indole).
6-Nitro-1H-indole (cas: 4769-96-4) belongs to indole derivatives. Indole produced by Proteus, Pseudomonas, Escherichia and other species was shown to be a growth promoting factor in Arabidopsis thaliana.Indole was synthesized in moderate yield via an o-naphthoquinone catalyzed tandem cross-coupling of substituted aniline and benzylamine under aerobic oxidation conditions.Safety of 6-Nitro-1H-indole
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