Studies on chemical modification of monensin IX. Synthesis of 26-substituted monensins and their Na+ ion transport activity

The C-26 modified monensin derivatives, 26-O-benzoylmonensin (3), 26-O-benz ylmonensin (4) and 26-phenylaminomonensin (5) were prepared from monensin ( 1), Na+ ion transport activity through biological membrane and antibacteria l activity of 3-5 were evaluated and compared with the activities reported for a 26-phenylurethane derivative (2), Among these compounds, 5 showed the largest Na+ ion transport and antibacterial activities. In these compounds , the formation of head-to-tail hydrogen bonds was suggested to be an impor tant factor for Na+ ion transport and antibacterial activities.