Design and Synthesis of an Activity Probe for Protein Tyrosine Phosphatases

Abstract Protein tyrosine phosphatases (PTPases) are an important class of enzymes involved in the regulation of many cellular events. Here we describe the design and synthesis of an activity probe 2 targeting these PTPases. This mechanism‐based activity probe adopts a cassette‐like design; a phosphate group serves as the recognition head and a fluorescent diethylaminocoumarin derivative acts as the reporter group. Compound 3 was phosphorylated with diallyl phosphorochloridate and then fluorinated with DAST to give versatile intermediate 5. The Boc protective group of compound 5 was removed by TEA to make available the amino group where a diethylaminocoumarin chromophore was later attached. Final deprotection of the allyl group from the phosphate head gives our complete activity probe 2. It will be used in the labeling study of PTPases from various sources.