Synthesis and biological evaluation of potential substrates for the isolation of the strigol receptor

A series of analogues derived from (+)-strigol, which is a germination stimulant for seeds of the parasitic weeds Striga and Orobanche, has been prepared. For the isolation and characterization of the strigol receptor, labelled analogues are required in which a photoreactive function may be incorporated. The synthetic strategy allows for the synthesis of a range of A-ring substituted analogues of GR24 (which is a strigol analogue), including fluorescent dansyl GR24 10. Bioassays reveal that the stimulatory activity of these analogues in the seed germination of Striga hermonthica is retained.