Synthesis of chlorine-substituted naphtho- and benzisoindolinium salts by base-catalyzed intramolecular cyclization of ammonium salts
It was shown that ammonium salts containing a propargyl group together with 3-α-naphthyl-2,3-dichloroallyl or 3-p-tolyl-2,3-dichloroallyl groups undergo cyclization-dehydrochlorination in an aqueous alkaline medium, forming chlorine-substituted naphthisoindolinium and benzisoindolinium salts. If the 3-phenylpropargyl and 3-p-tolyl-2,3-dichloroallyl groups are both present in the molecule of the ammonium salt the latter group enters exclusively into cyclization as diene fragment.