STRUCTURES OF NEW ANTIBIOTICS NAPYRADIOMYCINS

Abstract

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-[[(1 R, 3S)-3-chloro-2, 2-dimethyl-6-methylenecyclohexyl]methyl]-3, 10a-dihydro-6, 8-dihydroxy-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.