Development of NK3R Antagonists with a Labile Functional Group in the Natural Environment

For development of novel NK3R antagonists with reduced environmental toxicity, a structure-activity relationship study of an NK3R antagonist, talnetant, was conducted. Among several talnetant derivatives with labile functional groups in the natural environment, a 3-mercaptoquinoline derivative exhibited comparable biological activity to that of the parent talnetant. Additionally, 3-mercaptoquinoline was converted into the disulfide or isothiazolone form by air-oxidation, both of which showed no binding affinity to NK3R.