Exocyclic-endocyclic N-acyliminium ion equilibration via an intramolecular α-thioamidoalkylation in the synthesis of fused N,S-heterocyclic systems: Some new parameters was written by Hucher, Nicolas;Pesquet, Anthony;Netchitailo, Pierre;Daich, Adam. And the article was included in European Journal of Organic Chemistry in 2005.Category: indole-building-block This article mentions the following:
The reactivity of N-[aryl(or alkyl)thio(or seleno)]alkylamidals bearing the N-(CH2)n-X-(CH2)m-Ar functionality towards neat TFA has been examined These substrates give both the products of the “expected” π-cyclization process and “unexpected” products resulting from a new tandem heteroamidoalkylation/isomerization/π-cyclization. E.g., TFA catalyzed the reactions of α-hydroxy lactam I to give a mixture of II and III (92% yield, ratio 5.5:4.5). The composition of the final isomeric mixture depends on the temperature of the reaction, with a high selectivity in favor of the “expected” π-cyclization product as a thermodn. isomer. Furthermore, the results demonstrate again the relevance of TFA catalysis and support two reaction pathways involving the formation of an aza-sulfonium cation as a valuable intermediate which undergoes the π-cyclization process alone or in tandem with the thiocyclization/isomerization to give the cyclized products cited above. For the latter tandem reaction, we have established clearly that the n value should be equal to 1, the process can be performed independently for both the succinimide and phthalimide series, the reaction depends on the nucleophilicity of the heteroatom, and can be generalized to other heterocycles. Only the role of the benzene substitution has still to be totally elucidated. In the experiment, the researchers used many compounds, for example, 2-(Phenylthio)isoindoline-1,3-dione (cas: 14204-27-4Category: indole-building-block).
2-(Phenylthio)isoindoline-1,3-dione (cas: 14204-27-4) belongs to indole derivatives. Indole, first isolated in 1866, and it is commonly synthesized from phenylhydrazine and pyruvic acid, although several other procedures have been discovered. Moreover, it is known that it controls biofilm formation. However, the role of indole in the cell has not been fully elucidated.Category: indole-building-block
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