Optically active derivatives of imidazolines. alpha-Adrenergic blocking properties

The synthesis and alpha-adrenergic blocking activity of a series of optically active 2,4-disubstituted imidazolines are presented. The substituted analogues of naphazoline, tolazoline, and clonidine possess moderate alpha-adrenergic blocking activity with -log KB values in the range from 4.77 to 6.57. The differences between the alpha-adrenergic blocking activity of the stereoisomers of the 2,4-disubstituted imidazolines were small or insignificant in the rabbit aortic tissue preparations.