Synthesis and biological evaluation of 6-aryl-6H-pyrrolo[3,4-d]pyridazine derivatives as high-affinity ligands of the alpha(2)delta subunit of voltage-gated calcium channels.

A novel class of 2H-pyrrolo[3,4-c]pyridazine ligands of the alpha (2) delta subunit of voltage-gated calcium channels is described. Compound 4a with high affinity toward alpha (2) delta was identified through structure-activity relationship studies of the lead compound. Tritiated ligand [(3)H]-4b was synthesized to demonstrate that this ligand binds to the same site as Gabapentin toward alpha (2) delta subunit of voltage-gated calcium channels.