Studies on the photocyclization reaction of 8‐styryl‐substituted coralyne derivatives

Abstract

Listen

Translate article

AbstractThe photoreactivity of four 8‐styryl‐substituted coralyne derivatives was examined by UV/VIS‐ and 1H‐NMR‐spectroscopy. Except for the dimethylamino‐substituted derivative, these cationic azoniaheterocyclic dyes undergo photocyclization that most likely proceeds through an initial E‐Z‐isomerization of the double bond. Subsequent oxidation of the intermediates under aerobic conditions gave the pyrrolo‐annelated quinolizinium derivatives as final products, thus providing a useful synthetic route to polycyclic azoniahetarene derivatives. The 6‐(4‐chlorophenyl)‐substituted pyrroloquinolizinium derivative was isolated on a preparative scale, and the investigation of its photophysical properties revealed significantly red‐shifted absorption (λabs = 465–480 nm) and emission bands (λfl = 550–562 nm) in comparison to the parent coralyne and the styryl‐substituted derivatives.