Gilvocarcins, new antitumor antibiotics. 2. Structural elucidation

Gilvocarcin V(1), C27H28O9, m.p. 264 approximately 267 degrees C (dec.), and gilvocarcin M(2), C26H26O9, m.p. 245 approximately 248 degrees C (dec.), are new antitumor antibiotics produced by Streptomyces gilvotanareus. The structure of gilvocarcins has been determined by chemical degradation, nmr and mass spectra. They have a benzonaphtopyran-one system, to which the furanose moiety is linked through a C-C glycosyl bond.