Heterocyclic mesomeric betaines. Part 1. Synthesis and cycloaddition reactions of hetero derivatives of the phenalenide anion

Abstract

Conjugated heterocyclic mesomeric betaines (9; R = Ph, Me, and H) which are isoconjugate with the alternant phenalen-1-ide anion (1) have been synthesized. 8-Aminoquinoline and α-halogeno ketones yield the salts (10). These salts and triethylamine yield the conjugated heterocyclic mesomeric betaines (9) which cannot be isolated, but have been characterized by 1,3-dipolar cycloaddition with acetylenic and olefinic dipolarophiles. Dehydrogenation of some of the cycloadducts (11), (15), and (16) yield the corresponding conjugated cyclazine derivatives (12), (17), and (18). Hydrolysis of the esters (17) and (18) followed by thermal decarboxylation yields the novel cyclazines (21).