Synthesis and Intracellular Localization of 5,6‐Disubsutituted Pyrido[1′,2′;2,3]imidazo[5,1‐a]isoquinolinium Iodides

Abstract

AbstractNovel pyrido[1’,2’;2,3]imidazo[5,1‐a]isoquinolinium iodides independently substituted at their 5‐ and 6‐position were prepared from 5‐iodopyrido[1’,2’;2,3]imidazo[5,1‐a]isoquinolinium iodides using Suzuki‐Miyaura cross‐coupling reaction. The desired coupling products had cationic extended π‐conjugated skeletons and fluoresced strongly in the 420–460 nm region in methanol. In cell staining assay, the 5‐styryl‐substituted compounds, which showed lower fluorescence quantum yields in methanol, emitted high fluorescence in the intracellular environment and were specifically distributed to the endoplasmic reticulum.