Structures of new antibiotics napyradiomycins

Structures of novel antibiotics, napyradiomycins A, B1, B2, B3, C1 and C2 were determined. By X-ray crystallography, napyradiomycin B2 was determined to be (3R,10aR)-3-chloro-10a-[[(1R,3S)-3-chloro-2, 2-dimethyl-6-methylenecyclohexyl]methyl]-3,10a-dihydro-6,8-dihydro xy-2, 2-dimethyl-2H-naphtho[2,3-b]pyran-5,10-dione. The structures of other napyradiomycins were elucidated by NMR studies. Napyradiomycins C1 and C2 have unique structures which contain 14-membered ring cyclized by carbon-carbon bond.