Organocatalytic Aza-Michael/Michael Cyclization Cascade Reaction: Enantioselective Synthesis of Spiro-oxindole Piperidin-2-one Derivatives was written by Tang, Qing-Gang;Cai, Sen-Lin;Wang, Chuan-Chuan;Lin, Guo-Qiang;Sun, Xing-Wen. And the article was included in Organic Letters in 2020.Quality Control of 4-Bromoindoline-2,3-dione This article mentions the following:
A simple, direct and highly enantioselective synthesis of spiro-oxindole piperidin-2-one derivatives was achieved through an aza-Michael/Michael cyclization cascade sequence using a squaramide catalyst. The desired products were obtained in excellent yields (up to 99%) and good to high stereoselectivities (up to >20:1 dr and up to 99% ee) under mild conditions. In the experiment, the researchers used many compounds, for example, 4-Bromoindoline-2,3-dione (cas: 20780-72-7Quality Control of 4-Bromoindoline-2,3-dione).
4-Bromoindoline-2,3-dione (cas: 20780-72-7) belongs to indole derivatives. Indole, also called Benzopyrrole, a heterocyclic organic compound occurring in some flower oils, such as jasmine and orange blossom, in coal tar, and in fecal matter. It is used in perfumery and in making tryptophan, an essential amino acid, and indoleacetic acid (heteroauxin), a hormone that promotes the development of roots in plant cuttings.Quality Control of 4-Bromoindoline-2,3-dione
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