Studies on the Synthesis of Indothiazinone and Its Derivatives via Direct 3-Acylation of Indole

<div><p></p><p>Indothiazinone is a natural 3-acylindole alkaloid, isolated from a culture of myxobacterial strain. It was found to possess antibacterial activity against yeast and filamentous fungi. Indothiazinone is also structurally related with a mammalian endogenous aryl hydrocarbon receptor ligand, (2-(1′<i>H</i>-indole-3′-carbonyl)thiazol-4-carboxylic acid methyl ester (ITE). In this article, the synthesis of indothiazinone has been disclosed for the first time. Key feature includes direct and selective 3-acylation of indole in the presence of Lewis acid. In addition, an efficient preparation of <i>N</i>-substituted indothiazinone derivatives has been demonstrated.</p></div>