Heterocyclic compounds with bridgehead nitrogen atoms. Part 8. The synthesis and properties of cyclopenta[4,5]azepino[7,1,2-cd]pyrrolizine (cyclopenta[H][2.2.4]cyclazine)

Abstract

The title compound is obtained (i) by the reaction of 5-(NN-dimethylaminomethylene)-1-(NN-dimethyliminiomethyl)cyclopenta-1,3-diene perchlorate with the conjugate base of 3H-pyrrolizine or (ii), in better yield, by the reaction of 3,5-bis-(NN-dimethylaminomethylene)-3H,5H-pyrrolizinium perchlorate with the conjugate base of cyclopentadiene. The compound resembles azulene in its visible and near-u.v. spectrum and in the ease of electrophilic attack in the five-membered carbocyclic ring (positions 6 and 8). Products of acylation, nitration, nitrosation, bromination, and NN-dimethylaminomethylation are described.