Phosphinyloxy propanaminium inner salt derivatives

The invention concerns the compounds of formula (I) where the substituents have various meanings, in free acid form or in salt, physiologically hydrolysable ester or pro-drug form. They can be prepared by various procedures, e.g. coupling accompanied by oxidation or thiolation and hydrolysis or thiolysis, or by reduction to amino of a nitro substituent on an aromatic ring. They possess hypoglycemic activity and are thus indicated for use in the treatment of diabetes.