Effect of Alkynyl Group on Reactivity in Photoaffinity Labeling with 2-Thienyl-Substituted alpha-Ketoamide

Minimalist photo-reactive probes, which consist of a photo-reactive group and a tag for detection of target proteins, are useful tools in chemical biology. Although several diazirine-based and aryl azide-based minimalist probes are available, no keto-based minimalist probe has yet been reported. Here we describe minimalist probes based on a 2-thienyl-substituted alpha-ketoamide bearing an alkyne group on the thiophene ring. The 3-alkyne probe showed the highest photo-affinity labeling efficiency.