1H-Benz (de) isoquinoline -2 (3H) -acetic acid derivatives, processes for their preparation, pharmaceutical compositions containing same and their use

The invention concerns new compounds of formula I in which X and Y are independently O or S, with the proviso both are not O or S, and Z is H or thiophenyl, a therapeutically acceptable organic or inorganic salt thereof or an ester thereof. The acids and salts are useful in the treatment of diabetes in mammals and the invention includes pharmaceutical compositions containing the active compounds. Processes for the preparation of the compounds are also described. The invention also includes the esters of the acids of formula I, from which the acids may prepared by hydrolysis.