A structural investigation of the antibiotic rubiflavin. Preliminary communication

Abstract

SummaryRubiflavin is shown to be a mixture of antibiotics. The main components have been named rubiflavin A (3) and rubiflavin B (2) and are identified by NMR. spectroscopy as desacetylpluramycin A and kidamycin, respectively.

Functional Evaluation of Penile Hemodynamics

“…The organic group achieved no complete rigidity after an identical papaverine injection following a prolonged response time. These results as well as those by Nadig, 20 and Jünemann 21 and Sidi 22 and their associates are compatible with our results. Buvat and associates 23 performed the papaverine test (80 mg.) recommended by Virag and associates 19 following dynamic cavernosography.…”

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

“…The chromophore, ring E and the side chain were clearly the same as in pluramycin A. The configurations of the epoxide and the double bond in the side chain were determined unambiguously from the IH_ and 13C-NMR spectra (67). Peracetylation of rubiflavin A (10) gave a compound whose IH-NMR spectrum was virtually the same as that of diacetyl pluramycin A (12) (65).…”

“…Many years later, the investigation of a prepurified sample of rubiflavin by HPLC and NMR-spectroscopy clearly indicated that it was a complex mixture (67). So far, nine components have been identified from this mixture.…”

“…Hence the structural differences amenable to separation techniques are rather small and the isolation of pure compounds is accordingly very difficult. Compounds, which earlier were thought to be uniform now prove to be mixtures when subjected to modern chromatographic techniques such as HPLC (67).…”

Determination of the Relative Configurations in the Side Chains of the Antibiotics Hedamycin and Pluramycin A; Synthesis and NMR. Data of Suitable Model Compounds

“…Confirmation came from the carbonyl chemi-cal shifts: the C=O of 17 appears at higher field than the one of 16, as expected. Reinvestigation of the assignments of the olefinic C-resonances in these compounds by selective H-decoupling experiments revealed, that the assignments given in our preliminary communications on hedamycin [3], pluramycin A [2] and rubiflavin [22] should be interchanged. Three ways may be envisaged to solve this problem: transformation of the diepoxy esters to derivatives whose configurations can be more readily determined, stereoselective synthesis instead of the rather general and unselective routes described above, and comparison with related substances of known configuration.…”