The structure of the antibiotic hedamycin—III

A structural investigation of the antibiotic rubiflavin. Preliminary communication

“…spectrum of the crude 'rubiflavin' obtained from Aszalos et al further indicated its close relation to the pluramycin antibiotics. The spectrum displayed all the resonances of the two tetrahydropyran rings E and F as in the corresponding spectra of hedamycin (1) and kidarnycin (2) [6]. These data show that rings E and F are not acetylated in 'rubiflavin', which is consistent with the IR.…”

“…The 13C-NMR. signals of 'rubiflavin' in the region of sp2-hybridized C-atoms also corresponded more or less to those usually observed in pluramycin antibiotics [6]. However, here as well as in the methyl region, signal clusters were observed, indicating that 'rubiflavin' was a mixture, the components of which seemed to differ only in the side chain at C (2).…”

The Antibiotics of the Pluramycin Group (4 H-Anthra [1,2-b] pyran Antibiotics)

“…It must be pointed out that when the phenol is acetylated C(12) seems to have an extremely long relaxation time. The signal of this carbon becomes very weak and is easily lost in the noise when the spectral parameters such as flip angle and pulse repetition time are not adjusted appropriately (50,86).…”

“…The compound proved to be rather interesting in connection with the structure determination of kidamycin (29), the conformational analysis of ring F (86), and some first experiments towards an understanding of the structure-activity relationship with the pluramycins (24).…”

Isolation and Structure Elucidation of Some Components of the Antitumor Antibiotic Mixture ‘Rubiflavin’

“…This spectrum fully corroborated the structural features derived so far. The resonances of the aromatic and of the two sugar moieties were identical with the corresponding signals of hedamycin (1) [9]. The resonances of the side-chain C-atoms were observed at 134.0 and 123.3 ppm (C(18) and C(17), double bond), at 61.1 and 59.1 ppm (C(16), C (14), epoxide), and at 14.5 and 13.8 pprn (C(15), C(19), CH, groups).…”