Quinolizinium-based fluorescent probes for formaldehyde detection in aqueous solution, serum, and test strip via 2-aza-Cope rearrangement.

Formaldehyde is an abundant contaminant in food and environments causing various diseases. Thus, the development of fast, simple, and selective formaldehyde detection is of great interest. Herein, novel quinolizinium-based fluorescent probes were designed based on a 2-aza-Cope rearrangement reaction and showed high selectivity to formaldehyde by fluorescence emission shift. We successfully reduced the detection time by increasing the bulkiness of the homoallylic moiety. The probes were applied to detect formaldehyde in aqueous solution, serum, and paper format.

Fluorescent Labelling of Glycans with FRET-Based Probes in a Gold(III)-Mediated Three-Component Coupling Reaction.

Single-site multifunctionalization of glycans is of importance in biological studies considering its crucial role in mediating biological events and human diseases. In this paper, a novel approach for multifunctional labelling of glycans has been developed featuring the use of fluorescence resonance energy transfer-based (FRET-based) probes for fluorescent labelling of glycans through a gold(III)-mediated three-component coupling reaction. Oxidation of glycans into aldehydes followed by the A3 -coupling reaction with FRET-based probes resulted in the single-site formation of fluorescent propargylamine products. The conversion of labelled glycans can be revealed by ratiometric analysis of the FRET signals. This labelling approach results in multifunctionalization of glycans with high selectivity and conversion between 66 and 69 %.