Synthesis and Characterization of Fluorescent Brightening Agents with Chiral 2(5H)-Furanone and Bis-1,2,3-triazole Structure

Abstract

The multifunctional fluorescent brightening agents (FBAs) simultaneously possessing chiral 2(5H)-furanone and bis-1,2,3-triazole moieties are synthesized as designed via the Click reaction of N-[(5S)-5-menthoxy-2(5H)-furanonyl] amino acid propargyl esters with 4,4′-diazidostilbene-2,2′-disulfonate sodium salt tetrahydrate in high yields (over 90%). Their structures are systematically characterized. In addition, the testing results of their properties from fluorescence spectroscopy, photoisomerization, and ultraviolet (UV) protection factor (UPF) test show that the novel FBAs have excellent fastness to acid and light, as well as UV resistance. Especially, when a larger alkyl group in the side chain of amino acid moiety is introduced into the structure of the FBA, the designed compound has a better fluorescent brightening effect as anticipated. Moreover, in the experiments of its sorption on paper fibers, the scanning electron microscopy (SEM) images with it show a rough surface, while others without it sho...