Novel compounds useful as hypotensive agents are presented having the general formula I ##STR1## wherein R.sub.1 represents a lower aliphatic acyl group, a straight or branched chain alkyl or alkenyl group or an aralkyl group of the general formula ##STR2## wherein R.sub.2 represents hydrogen, a lower alkyl group or a halogen atom. Furthermore, new therapeutic compositions of matter are also described incorporating the above novel 3-substituted-2(1H)pyridone-6-carboxylic acids (I) as an active ingredient with carriers and showing uses as hypotensive agents. These new compounds of the formula I are prepared either by reacting D-glucaro-.delta.-lactam or its salt with an acid anhydride or by reacting 3-hydroxy-2(1H)pyridone-6-carboxylic acid with an acyl anhydride or alkyl halide, aralkyl halide and an alkenyl halide.