XCIII.—Polynuclear heterocyclic aromatic types. Part I. Some indenoquinoline derivatives

Abstract

leads to the conclusion that many aromatic types as yet unknown should be capable of existence, and in the present series of investigations it is proposed to survey the field of the heterocyclic substances from this point of view and with the particular object of throwing light on the conditions underlying the manifestation of the phenomenon of cyclic conjugation. At the present time, authentic derivatives of pentamethine, (CH),, the lower ring homologue of benzene, are