[New stereoselective catalysts in doxycycline synthesis]. / Novye stereoselektivnye katalizatory v sinteze doksitsiklina.

Formation of the doxycycline diastereoisomer along with doxycycline during hydrogenation of the methacycline exocyclic double bond lowered the yield of the main product. The use of tris-(triphenylphosphine)-rhodium chloride (Wilkinson catalyst) as a catalyst provided higher stereoselectivity of the hydrogenation and resulted in predominant production of doxycycline. Inclusion of some ligands such as hydrazine or others into the composition of the compound rhodium catalyst increased its activity. The stereoselectivity during hydrogenation of the methacycline exocyclic double bond can be explained by different rates of hydrogen attachment to the two enantiomeric products of the compound rhodium catalyst addition to the exocyclic double bond.

[Study of conformation structure and molecular interactions of rosamycin by infrared spectrum analysis]. / Issledovanie konformatsionnoi struktury i molekuliarnykn vzaimodeistvii rozamitsina po IK-spektram.

IR spectra of rosamycin and its solutions in inert (CCl4 and C2Cl4), proton acceptor (tetrahydrofuran, hexametapol and diethylamine) and proton donor (CHCl3 and CH3OD) solvents were studied at various concentrations (0.1 to 0.001 mol/l) and temperatures (20 to 100 degrees C) in the region of the vC = O and vOH absorption bands (1600-1800 and 3200 3650 sm 1). It was found that the absorption bands at 3480 and 3560 sm-1 observed in the spectra of rosamycin diluted solutions in the inert solvents referred to variations of vOH...N of the aminosugar fragment and to vOH...O = C of the ester group of the macrocycle. Bands at 1697 and 1717 sm-1 referred to vC = O of the ketone and aldehyde carbonyl groups and band at 1728 sm-1 referred to vC = O of the ester group whose carbonyl was involved in the C = H...HO intramolecular hydrogen bond. Intensity of vC = O band (1745 sm-1) of the free ester group was nought. However, it increased with using the proton acceptor solvents. OH...N and OH...O = C intramolecular hydrogen bonds stabilized rosamycin molecule conformation. Mechanism of rosamycin interaction with the proton donor and acceptor molecules was elucidated. It was shown that tertiary nitrogen was the center of rosamycin molecule protonation.

[IR spectral research on erythromycin mono- and dihydrates]. / Issledovanie mono- i digidrata éritromitsina po IK-spektram.

The IR spectra of crystalline and amorphous forms of erythromycin monohydrate and dihydrate were investigated and their characteristic spectral features were described. Differences in the system of the intermolecular hydrogen bonds and in the level of perfection of the crystalline structures of the monohydrate and dihydrate were detected. It was shown that both crystallohydrates of erythromycin might exist in two polymorphous modifications. The crystalline structure of the low temperature modification of the monohydrate was of low perfection. At 75-80 degrees C irreversible polymorphous conversion of erythromycin monohydrate and erythromycin dihydrate accompanied by changes in the hydration water state was observed. The crystalline structures of high temperature modifications of the erythromycin crystallohydrates were identical.

[Infrared spectra and the molecular conformations of macrolide-group antibiotics in solution]. / Infrakrasnye spektry i knoformatsii molekul nekotorykh antibiotikov gruppy makrolidov v rastvore.

IR spectra (1,600-1,800, 3,100-3,700 cm-1) of tetrachlorethylene solutions of macrolide antibiotics such as erythromycin monohydrate and dihydrate, oleandomycin, erythrolose amine and anhydroerythromycin were obtained. The atoms and atomic groups included into the hydrogen bond were determined. It was shown that the antibiotic molecule conformations were stabilized by the intramolecular hydrogen bonds.

[Isolation and study of the antibiotics produced by a culture of Str. iverini (Gause et al., 1957) Pridham et al., 1958]. / Vydelenie i izuchenie antibiotikov, produtsiruemykh kul'turoi Str. iverini (Gause et al., 1957) Pridham et al., 1958.

An antibiotic complex consisting of echinomycin and triostin A was isolated from Str. iverini (Gauze et al., 1957) Pridham et al., 1958. Hydrolysis of the antibiotics resulted in formation of an aglycone identified with quinoxaline carboxylic acid. The UV spectrum of the aglycone and the antibiotics of the echinomycin-triostin group was studied.

[New anthracycline antibiotics taurimycins A and B produced by a Str. tauricus No. 7036-1 culture]. / Novye antratsiklinovye antibiotiki tavrimitsiny A i B, produtsiruemye kul'turoi Str. tauricus No. 7036-1.

Taurimycins A and B are new anthracycline antibiotics belonging to the group of glycosides. They were isolated from the mycelium of culture 7036-1 classified with Str. tauricus. The empiral formula of taurimycin A is C14H51O16N,M+813. The empirical formula of taurimycin B is C41H49O16N,M+811. The absorption maxima in the UV spectra of the antibiotics (in alcohol solutions) were observed at 235, 257, 292, 466, 482, 494, 515 and 527 nm. The IR spectra showed absorption bands at 3450, 2945, 2870, 1740 and 1610 cm-1. Hydrolysis of the antibiotics with hydrochloric acid resulted in formation of an aglycone identified as epsilon-pyrromycinone.

[Isolation of the new antibiotic variamycin B from the biosynthetic products of a Streptomyces olivovariabilis sp. nov. culture]. / Vydelenie novogo antibiotika variamitsina B iz produktov biosinteza kul'tury Streptomyces olivovariabilis sp. nov.

Variamycin B, a new antitumor antibiotic was isolated from metabolic products of Streptomyces olivovariabilis sp. nov. The empirical formula of variamycin B is C52H76O24, the melting point is 163-165 degrees C (dec.), (alpha)20D--30 +/- 2 degrees (C 0.5, alcohol), the UV-spectrum: lambda max 230, 279, 317, 330, 415 (lg E 4.27, 4.6, 3.83, 3.75, 3.95), IR-spectrum: 1080, 1170, 1380, 1570, 1640, 1720, 3400 cm-1. Variamycin B is classified as belonging to the group of antibiotic analogs of aureolic acid. Chromomycinone, tetrazide and residues of two 2,6-didesoxysugars, i.e. olivose and variose were obtained as a result of complete and partial acid degradation of variamycin B. It was shown with the data of quantitative analysis of the hydrolysates obtained on complete hydrolysis of variamycin B that the ratio between the residues of variose and olivose in the antibiotic molecule was 1 : 4. Oxidation of variamycin B with Fremi salt resulted in formation of chinone having chromomycinone-chinone, 2 residues of olivose and 1 residue of variose in its composition. Investigation of the products of partial hydrolysis provided isolation of a substance having aglicone-chromomycenone and 4 residues of olivose in its composition. A partial structure of variamycin B is proposed.

[Identification of the antibiotic formed by a Str. canulus 106/78 culture with antibiotic CC-1065]. / Identifikatsiia antibiotika, obrazuemogo kul'turoi Str. canulus 106/78, s antibiotikom CC-1065.

An antibiotic with a melting point of at least 340 degrees C, [alpha]D + 100 degrees (c 1 per cent in dimethylformamide) was isolated from the mycelium of Str. canulus 106/78. Calculated (%): C 60.63, H 4.69, N 13.6. The UV spectrum of the antibiotic (in methanol solution) showed the terminal absorption, shoulder at 265 nm and maximum at 375 nm. In dimethylformamide solution the UV absorption maximum was observed at 370 nm with E1 1% cm 845. The IR, FMR and 13C-NMR spectra of antibiotic 106 are analogous to the respective spectra of antibiotic CC-1065 which is indicative of their identity.

[Process of sodium fusidate inactivation as affected by oxygen and humidity]. / Izuchenie protsessa inaktivatsii fuzidata natriia pod vliianiem kisloroda i vlagi.

The effect of oxygen and moisture on stability of sodium fusidate was studied. It was shown that inactivation of the antibiotic in the atmosphere of oxygen was due to its oxidation in the preparations with low humidity levels. In the preparations with high humidity levels, the main cause of the antibiotic inactivation was hydrolysis with respect to C-16-O-acetyl group. When sodium fusidate was air stored, the salts of 24, 25-dioxy-and 24, 25-dioxy-11-monoketofusidic acids were identified among the products of its inactivation. The salts of 24,25-dioxy-11-monoketofusidic acid were also prepared by oxidation of fusidic acid with potassium permanganate in a weak alkaline medium. The possibility of using sodium sulfite and metabisulfite as stabilizers for th antibiotic storage was shown.

[New antibiotic, cinropeptin, from a culture of Act. cineraceus]. / Novyi antibiotik tsinropeptin iz kul'tury Act. cineraceus.

Cinropeptin, a new antibacterial antibiotic, was isolated from the mycelium of a culture classified as belonging to Act. cineraceus. Its empirical formula is C50H63N11O12S6, [alpha]D--169.4 degrees (C 0.36, CHCl3). The UV absorption maxima of the antibiotic in an alcoholic solution were observed at 218, 232, 304 and 365 nm. The IR absorption bands were recorded at 3370, 1660, 1600, 1530, 1140 and 1100 cm-1. Cystin, glycine and methylamine were detected in the acid hydrolysate of cinropeptin. Study on the products of the antibiotic partial oxidation with performic acid and comparison of the sulfur percentage and molecular weight showed that the molecule of cinropeptin contained 3 residues of cystin.

[A new antibiotic, corallomycin, from an Act. longispororuber]. / Novyi antibiotik korallomitsin iz kul'tury Act. longispororuber.

A new antibiotic named corralomycin (C34H28O9) was isolated from the mycelium of culture 6795-38 classified as belonging to Act. longispororuber. The maximum UV absorption spectra of the antibiotic in an alcohol solution were observed at the wavelengths of 228, 268 and 420 nm, the absorption bonds of 3400, 2980, 2865, 1710, 1625, 1595, 1165, 880 and 780 cm(-1) were recorded in the IR spectrum. Two acetyl derivatives of corallomycin, i.e. diacetate (C38H32O11) and tetraacetate (C42H36O13) were prepared.