The invention provides compounds of the formula: ##STR1## wherein each of R.sub.1, R.sub.2 and R.sub.3, which can be the same or different, is hydrogen, chloro, bromo, fluoro, methyl, ethyl, methoxy, amino, hydroxy or nitro; R.sub.4 is hydrogen or alkyl of 1 to 7 carbons atoms; X is ##STR2## (R.sub.5 is hydrogen or hydroxy) and n is 1-4; and their non-toxic pharmaceutically acceptable acid additions salts. These compounds exhibit valuable pharmacological activity and are useful in the treatment of mammals, especially as anti-hypertensive agents. Furthermore, some of the compounds have proved to possess diuretic, .beta.-blocking activity and/or antithrombotic activity. The compounds may be made by a variety of methods and may be incorporated in pharmaceutical compositions also comprising a compatible pharmaceutically acceptable carrier.