1,3-Dihydro-2,1,3-benzothiadiazol-2,2-diones and 3,4-dihydro-1H-2,1,3-benzothidiazin-2,2-diones as ligands for the NOP receptor.

Abstract A series of 1,3-dihydro-2,1,3-benzothiadiazol-2,2-diones ( I ) and 3,4-dihydro-1 H -2,1,3-benzothidiazin-2,2-diones ( II ) were prepared. While the five-member ring series ( I ) did not show good affinity for opioid receptors, the six-member ring series ( II ) exhibited extremely high affinity and selectivity for the NOP receptor and showed full agonist activity, as determined by stimulation of GTPγ[ 35 S] binding.