Syntheses of fluorescence-labeled artificial leaf-opening substances, fluorescent probe compounds useful for bioorganic studies of nyctinasty

In a previous paper, the syntheses of potassium galactolespedezate (1) and potassium galactoisolespedezate (2), artificial leaf-opening substances useful for bioorganic studies of nyctinasty were reported. The fluorescent probe compounds, fluorescence-labeled galactoisolespedezates (3, 10, 13), designed on the basis of 1 and 2, were prepared. In particular, compound 3 was bioactive at 5×10−5 M, one-fiftieth as strong as the natural leaf-opening substance. This fluorescent probe would be useful for bioorganic studies of nyctinasty.