Chemical modification of coriolin B

Several derivatives of 5-ketocoriolin B (8, 11, 12) chemically modified at C-8 have been synthesized. These derivatives showed antitumor and antibacterial activity of the same degree as 5-ketocoriolin B (4) and diketocoriolin B (5) which were the most active members of the known coriolin group antibiotics. These derivatives were more stable than 4 and 5 in acidic or alkaline solution.