No abstract

Very recently, ToMITA and coworkers' 2) have reported the fermentation, isolation and structure elucidation of gilvocarcins V (1) and M (2). They note that I was previously described under the name of toromycin by HORII et al.3) although the structure of toromycin was not elucidated. Recently we have isolated 1 and 2 and a related compound gilvocarcin E (3) from a culture of Streptomyces anandii subsp. araffinosns strain C-22437 (ATCC-31431).* The producing culture was isolated at BristolLaboratories from a soil collected in Katpadi, Madras, India. We report here the isolation, structure elucidation and biological activities of compounds 1. 3. Isolation of Gilvocarcins V, M and E

The 13C NMR spectra at 25.2 MHz of the Zn(II) and Cu(II) complexes of the antitumor antibiotic bleomycin A2 are discussed. Complexation of the drug to Zn(II) causes 38 of the 52 resonance lines of bleomycin A2 to shift to new positions. All but ten of these shifted lines have been assigned in the Zn(II) bleomycin complex. Although the specific donor sites of the drug cannot be identified from the 13C NMR data, the analysis clearly shows that the pyrimidine-imidazole portion of the molecule is affected by chelation. This finding is in agreement with the previously reported metal-binding site of the antibiotic. The analysis also shows that carbon atoms which have large through-bond distances from the binding site can experience substantial chemical-shift changes upon metal binding. Complexation of the drug to Cu(II) eliminates 23 resonances from the spectrum of the molecule. All of these resonances emanate from carbon atoms which are located in the pyrimidine-imidazole portion of the drug.

While screening cultures of actinomycetes for novel antitumor substances we have isolated an anthracycline mixture, bohemic acid complex, from Actinosporangium sp. strain C36145 (ATCC 31127).1 In addition to the known antibiotics cinerubins A and B2 and pyrromycin,3

The structures of four new anthracyclines (rudolphomycin (11), collinemycin (12), mimimycin (13), alcindoromycin ( 14)) have been determined by a combination of chemical degradations and spectral interpretation. The use of ,3C NMR spectroscopy has been extensive and assignments to the 13C NMR spectra of these compounds have been made.