A series of pyridinyltetrahydropyridine derivatives was synthesized and evaluated as adrenoceptor and tetrabenazine
antagonists. 4-(3-Fluoro-2-pyridinyl)-1,2,5,6-tetrahydropyridpinroev ed to be the most potent and selective c y p -
adrenoceptor antagonist of the series as measured in vitro by displacement of [3H]clonidine and [3H]prazosin from
membrane binding sites of calf cerebral cortex and by antagonism of the effects of clonidine and methoxamine in
the rat isolated, field-stimulated vas deferens. In addition, this compound, and the corresponding desfluoro derivative,
blocked tetrabenazine-induced ptosis in the mouse.