The Witkop-Winterfeldt oxidation converts tetrahydropyridoindoles into pyrroloquinolones and cinnolines by an unprecedented scaffold rearrangement was written by Mentel, Matthias;Peters, Martin;Albering, Joerg;Breinbauer, Rolf. And the article was included in Tetrahedron in 2011.Application of 33439-27-9 This article mentions the following:
The Fischer indole reaction between phenylhydrazines and N-tosyl-4-piperidone furnishes tetrahydropyrido[4,3-b]indoles. In a Witkop-Winterfeldt oxidation using ozone, such indole derivatives are converted into medium-sized dicarbonyl ring systems, which cyclize to pyrroloquinolones. A detailed study of the reaction intermediates and the characterization of a cinnoline betaine side product formed by an unprecedented ring closure mechanism are reported. In the experiment, the researchers used many compounds, for example, 1-Tosylpiperidin-4-one (cas: 33439-27-9Application of 33439-27-9).
1-Tosylpiperidin-4-one (cas: 33439-27-9) belongs to piperidine derivatives. Piperidine is a saturated organic heteromonocyclic parent, an azacycloalkane, a secondary amine and a member of piperidines. Piperidine prefers a chair conformation, similar to cyclohexane. Unlike cyclohexane, piperidine has two distinguishable chair conformations: one with the N–H bond in an axial position, and the other in an equatorial position.Application of 33439-27-9
Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem