Chemical modification of the ester group of diketocoriolin B

5,8-Di-O-tetrahydropyranylcoriolin B (2) was synthesized and its two expoxide groups were found to be resistant to alkaline hydrolysis to give di-O-tetrahydropyranldihydrocoriolin (3). Acylation or alkylation of the free hydroxyl group at C-1 of 3 followed by hydrolysis of the tetrahydropyranylether groups and oxidation of the hydroxyl groups at C-5 and C-8 afforded a numer of 1-O-acyl or alkyl analogs of diketocoriolin B. All of them showed antibacterial and antitumor activities.