Preparation of a Colorimetric TLC Stain for Amines from Furfural

High Resolution Image Download MS PowerPoint Slide A laboratory experiment was developed for the preparation of a thin-layer chromatography stain from the condensation of furfural and N -methylbarbituric acid. The experiment allows for the introduction of the concepts of selective TLC staining and colorimetric detection of amines. The stain is based on the formation of donor–acceptor-Stenhouse-adducts (DASAs), and its preparation and application allow the introduction of organic chemistry concepts such as the Knoevenagel condensation, ring opening, and Nazarov electrocyclization, as well as photochromic systems. The cheap reagents required for this work and easy setup allow for a straightforward introduction of the work in various settings, including academic laboratories. The use of biomass-derived furfural reinforces the importance of green chemistry and sustainable practices in organic chemistry.