1-(Heterocyclylalkyl)-1,3-dihydro-2H-benzimidazol-2-ones, their preparation, their pharmaceutical compositions and their use as beta-adrenergic receptor blockers
Novel 1-(heterocyclylalkyl)-1,3-dihydro-2H-benzimidazol-2-ones, wherein said heterocyclyl group is a 3-pyrrolidinyl or 3-piperidinyl group, each substituted in the 1-position with a 3-aryloxy-2-hydroxypropyl, 3-arylthio-2-hydroxypropyl or 2-(2,3-dihydro-1,4-benzodioxin-2-yl)-2-hydroxyethyl group, said compounds having useful .beta.-adrenergic receptor blocking activity.