Geneserine and geneseroline revisited: acid-base catalyzed equilibria of hexahydropyrrolo-[2,3-b]-indole N-oxides with hexahydro-1,2-oxazino-[5,6-b]-indoles.

It is shown that geneserine [2] and geneseroline [4] convert with acid into salts of physostigmine N-oxide [3] and geneseroline N-oxide [5], respectively. Structure assignments were made on the basis of chemical conversions, 1H-nmr analysis of 2-5, and an X-ray analysis of 5 as its hydrochloride.