Synthesis and biological evaluation of 2-(arylethynyl)quinoline derivatives as mGluR5 antagonists for the treatment of neuropathic pain.

We described here the synthesis and biological evaluation of mGluR5 antagonists containing a quinoline ring structure. Using intracellular calcium mobilization assay (FDSS assay), we identified compound 5n, showing high inhibitory activity against mGluR5. In addition, it was found that compound 5n has excellent stability profile. Finally, this compound exhibited favorable analgesic effects in spinal nerve ligation model of neuropathic pain, which is comparable to gabapentin.

3-Hy-droxy-2-[(2E)-1-(2-hy-droxy-6-oxocyclo-hex-1-en-1-yl)-3-(2-meth-oxy-phen-yl)prop-2-en-1-yl]cyclo-hex-2-en-1-one.

In the title compound, C(22)H(24)O(5), each of the cyclo-hexenone rings adopts a half-chair conformation. The hy-droxy and carbonyl O atoms face each other and are orientated to allow for the formation of the two intra-molecular O-H⋯O hydrogen bonds which are typical of xanthene derivatives. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link mol-ecules into layers parallel to the ab plane.