- Effect of fluorine substitution on the adrenergic properties of 3-(tert-butylamino)-1-(3,4-dihydroxyphenoxy)-2-propanol. Adejare, A., Nie, J.Y., Hebel, D., Brackett, L.E., Choi, O., Gusovsky, F., Padgett, W.L., Daly, J.W., Creveling, C.R., Kirk, K.L. J. Med. Chem. (1991)