(R)-1,2,3,4-tetrahydro[1]benzothieno[2,3-c]pyridines: novel optically active compounds with strong 5-HT1A receptor binding ability exhibiting anticonflict activity and lessening of memory impairment.

(R)-1,2,3,4-Tetrahydro[1]benzothieno[2,3-c]pyridine derivatives (60-114) were synthesized. The (R)-isomers have affinity for the 5-HT1A receptor while the (S)-isomers have no such ability. The affinity of the (R)-isomers was discussed on the basis of structure-activity relationships between the affinity and hydrophobicity of the (R)-isomers. Compounds 71 and 107, which are representative derivative compounds, have anticonflict activity and lessening of memory impairment. In particular, compound 107 cannot bind to receptors other than the 5-HT1A receptor, demonstrating that it is a unique compound with a different mechanism of action from that of conventional anxiolytics.