Indole β-nucleophilic substitution. Part 3. Synthesis of four isomeric pyrido[x′,y′:5,6]oxepino[3,2-b]indolones

Abstract

Condensations of 2-lithio-1-phenylsulphonylindole with the four pyridine analogues of phthalide gave 1-phenylsulphonylindol-2-yl o-hydroxymethylpyridyl ketones, from which on treatment with base were obtained the title compounds, by a process of intramolecular Indole β-nucleophilic substitution. This new aspect of Indole chemistry is discussed in the context of other related processes.