Substituted (4-carboxyphenoxy) phenyl alkane compounds

A compound of the formula:

• ##STR34## wherein R.sub.1 is a C.sub.1 to C.sub.7 alkyl carbonyl unsubstituted or substituted with carboxyl or C.sub.1 to C.sub.6 alkoxy carbonyl group converted in the human body to a carboxylic acid group;
• R.sub.2 is hydrogen, lower alkyl or lower alkoxyl;
• R.sub.3 is hydrogen, halogen lower alkyl or lower alkoxyl;
• R.sub.4 is hydrogen, halogen, phenyl, lower alkyl, lower alkoxyl, halo-lower alkyl, nitro, or a carboxylic ester group;
• or R.sub.3 and R.sub.4 together form the residue of a benzene ring;
• Z is oxygen or sulphur;
• X is straight or branched chain lower alkylene or lower-alkylene-oxy;
• q is zero or an integer from 1 to 12;
• and
• one of m and n is zero and the other is one.