Autotransfer chromatography in the characterization of pyrroles. Chemistry of multiple-spot phenomena.

A characteristic pattern of five interconverting "component" zones is obtained on autotransfer chromatography when pure kryptopyrrole (KP) is adsorbed from aqueous solution onto charcoal and then eluted with methanol. Specific oxidation products (lactams) derived from synthetic KP matched four of the five zones. Zone 1 was obtained directly from the a'-hydroxy-a-lactam. Zone 3 was produced directly by the a'-methoxy-a-lactam, while zones 2 and 5 were formed as a consequence of its acid hydrolysis during equilibration and chromatographic development. The formation of the methoxy lactam itself depended upon the presence of added methanol in the extraction process. In the absence of methanol during extraction only zone 1 (sometimes accompanied by zone 4) was formed.