Abstract: Novel quinolones of formula I ##STR1## and pharmaceutically acceptable acid addition salts thereof in which the dotted line between positions 2 and 3 of the quinolone ring represents an optional bond, R is hydrogen, 1-methyl or 2-lower alkyl; R.sub.1 is lower alkyl; R.sub.2 is hydrogen, halo, lower alkyl, lower alkoxy, trifluoromethyl, cyano, difluoromethoxy, methylsulphinyl, phenylsulphinyl or the group --NR.sub.4 R.sub.5 or the N-oxide thereof wherein R.sub.4 and R.sub.5, which may be the same or different, are lower alkyl or, together with the nitrogen atom to which they are attached form a pyrrolidino, piperidino or morpholino radical; and R.sub.3 is hydrogen, fluoro, lower alkyl or lower alkoxy provided that, when R.sub.3 is lower alkoxy, R.sub.2 is other than lower alkoxy have utility as antihypertensive agents. Processes for preparing the quinolones and pharmaceutical compositions containing them are disclosed.