Synthesis of photoaffinity probes of tautomycin

Two types of photoaffinity probe, which possesses a benzophenone or a diazirine photophore on the 2-position of tautomycin, were prepared in order to prove the details of binding site to PP1. These photoaffinity probes were designed on the basis of the structure–activity relationship; thus, the diacid moiety is indispensable. The selective introduction of photolabeling units on the 2-position of tautomycin was achieved through the 2-oxime of tautomycin diacid.