The structure of ervinceine
UV spectrum: Xma x (ethanol) 248, 328 m/l (log ~ 4.12, 4.26), which is characteristic for a -methylene indol ine alkaloids. The NMR spectrum of ervinceine with signals at 8 8, 88 (NH, singlet), 6 .14-6 .91 (aromatic protons, 3H), [ 3.69 (singlet, COOCHs), 3.66 (singlet, OCHs), and 0.58 (triplet, --C--C~Hs). I The reduction of ervinceine with zinc in methanoiic sulfuric acid gave dihydroervinceine, C2zHz0NzOz, mp 118:119" C (methanol), [a]~3 +3.3 (c 0.9; chloroform). Its IR spectrum; Xrnax (ethanol) 249, 305 mg (log ~ 3.78, 3.73) is characteristic of ind0tine bases. Its mass spectrum has the molecular peak M + 370 (16%) and also peaks of ions with m/e 339 (M--OCH~) + I0%, 2~4 (M--86) + 26% and 124 (I00%).
A study of the alkaloids ofSenecia krylovii
hydrated silica in the system mentioned above. Substance A gave a single spot on chromatography in a thin layer of KSK silica gel and hydrated silica in neutral, acid, and alkaline systems: chloroform--methanol--water (62 : 31 : 7), 1-butanol--acetic acid--water (4 : 1 : 2); and n-propanol-17% ammonia (8 : 2). The Rf values of substance A, its melting poiat (about 250* C), the melting point of the acetate (160-163" C), and the IR spectrum were identical with the same figures for samples of Primula saponin given to us by N. I. Libizov (VILR [All-Union Scientific-Research Institute for Medicinal and Aromatic Plants]).
BIOSYNTHESIS OF DAUNORUBICIN GLYCOSIDES: ANALYSIS WITH BLOCKED MUTANTS
ABSTRACT Daunorubicin (daunomycin; NSC 82151) is an anthracycline antibiotic that is useful in the treatment of human leukemias. Several Streptomyces species accumulate higher glycosides of daunorubicin, which can be converted to daunorubicin by simple hydrolysis. We isolated a number of mutants of a daunorubicin glycoside-producing streptomycete, and found that some were deficient in accumulation of daunorubicin glycosides. One such mutant accumulated no detectable anthracyclines, while other mutants accumulated anthracyclines or aglycones that have not been reported before or have been described as co-metabolites of daunorubicin glycosides. Some of these anthracyclines and aglycones were purified and used as substrates in bioconversion experiments with various mutants. The results allowed us to construct a proposed pathway for the biosynthesis of daunorubicin glycosides by this streptomycete. KEYWORDS Anthracycline; daunorubicin; biosynthesis; blocked mutants; biotransformation.