Syntheses of novel photoaffinity probes for bioorganic studies on nyctinasty of leguminous plants

Novel and non-radioactive photoaffinity probes (1 and 2) for the bioorganic study of nyctinasty are designed and synthesized based on potassium isolespedezate (3), which induce leaf-opening against the leaf of Cassia mimosoides L. These probes bear a trifluoromethyldiazirine or diazophenyl group for photoaffinity and a biotin subunit for affinity chromatography and chemiluminescent detection. Probes (1 and 2) showed leaf-opening activity at 5×10−5 mol/L with leaves of C. mimosoides; thus, they would be an important tool for the identification of a receptor protein for 3.