Synthesis of novel benzoic acid derivatives with benzothiazolyl subunit and evaluation as aldose reductase inhibitors.

Several methyl benzothiazolyloxybenzoates, S-isosters, and the corresponding benzoic acids were synthesized and tested as aldose reductase inhibitors (ARIs). Out of this series, the ester derivative 2a-7 was found to exhibit the highest enzyme-inhibitoric activity. In order to investigate this unexpected result, further modifications were carried out which allowed us to explain this finding and to open a path to a novel class of ARIs.