Synthesis and photophysical properties of the biaryl systems of pyrrocytidine and furouridine with benzothiophene, benzofuran, and benzene as the aromatic extended moiety

Abstract

We have synthesized seven fluorescent pyrrocytidines (PyCs) and two furouridines (FuUs) with benzothiophene, benzofuran, and benzene as the aromatic extended moiety in the biaryl system. The benzothiophene and benzofuran extended moieties have a distinct influence on the photophysical properties of the pyrrocytidines and furouridines, such as their responses to polarity, pH and viscosity. Pyrrocytidine 4g with a methoxy in the benzene extended moiety exhibits a larger emission maximum and fluorescence quantum yield than the other nucleosides in most cases, indicating that the substituents in the benzene extended moiety in the biaryl system always play a key role in the photophysical properties.