A novel route to isoannulated heteroaromatic compounds 2. – The dipole route to furo/thieno pyrroles and α-pyridones, and their benzo derivatives was written by Bussenius, Jorg;Laber, Norbert;Muller, Thomas;Eberbach, Wolfgang. And the article was included in Chemische Berichte in 1994.COA of Formula: C8H4Br2S This article mentions the following:
A new methodol. involving 1,7-dipolar cyclizations of conjugated dipoles followed by a multistep rearrangement affording ring-contracted products has been employed for the synthesis of various examples of the title compounds Under different thermolysis conditions the annulated alkynyl nitrones are converted into isoannulated pyrroles and α-pyridones, resp., with yields up to 90%. The product distribution is strongly influenced by the nature of a terminal substituent R, hence supporting a mechanism with oxo carbenes as central intermediates which undergo either 6-π cyclization to the pyrrole systems of Wolff rearrangement leading to conjugates ketenes, the precursors of the observed α-pyridones. Diels-Alder reactions were performed with a benzofuropyridone derivative, naphthopyridone derivative, as well as with the corresponding dihydronaphtho compounds Whereas tert-Bu derivatives are rather un-reactive against dienophiles, they are easily transformed into cyclic imides under the influence of oxygen and light suggesting the formation and subsequent [4+2] cycloaddition of 1O2 as important steps. In the experiment, the researchers used many compounds, for example, 2,3-Dibromobenzo[b]thiophene (cas: 6287-82-7COA of Formula: C8H4Br2S).
2,3-Dibromobenzo[b]thiophene (cas: 6287-82-7) belongs to benzothiophene derivatives. Benzothiophene is used as starting material for the synthesis of bioactive molecules. The core structure is a part of various pharmaceutical substances and natural products. The different substitution patterns in these heterocycles offer new opportunities for drug discovery and other applications in materials science.COA of Formula: C8H4Br2S
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem