Sulfonation of 3,3′‐Diformyl‐BINOL for Enantioselective Fluorescent Recognition of Amino Acids in Water
Feng Zhao, Yalin Wang, Xuedan Wu, Shanshan Yu, Xiao‐Qi Yu, Lin Pu
Abstract
Abstract Reaction of ( R )‐3,3′‐diformyl‐1,1′‐bi‐2‐naphthol with concentrated sulfuric acid gives the corresponding 6,6′‐disulfonated compound ( R )‐ 2 selectively. This provides a simple and efficient method to convert a water‐insoluble compound to a water‐soluble fluorescent probe. It is found that ( R )‐ 2 in combination with Zn 2+ shows a highly enantioselective fluorescent response toward various amino acids in the aqueous HEPES buffer solution at pH 7.4. For example, an enantioselective fluorescence enhancement ratio [ ef =Δ I D /Δ I L ] up to 35.8 is observed for the recognition of asparagine. NMR and mass spectroscopic investigations are conducted to explore the reaction of ( R )‐ 2 with asparagine.