Thermal oxidation initiated in explosive detonation products by exothermal pyrolysis of metal acetylacetonates

Physics of the Solid State - Thermal interactions between solid-phase mixtures of metal acetylacetonates with ultradispersed diamond and explosive detonation products are investigated. It is shown...     

Analysis of glycosides of the dammarane series in natural and synthetic methods by high-performance liquid chromatography

The possibility has been shown of using the Milikhrom domestic microcolumn liquid chromatograph for the quantitative determination of glycosides of the dammarane series in commercial forms of ginseng and synthetic mixtures. To calculate the amounts of individual ginsenosides by the internal-standard method it is proposed to use dammar-24-ene-3,12,17,20(S)-tetraol 3,20-di-O--D-glucopyranoside as the internal standard.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 57–61, January–February, 1990.     

Triterpenoids from the leaves ofBetula costata

From the unsaponifiable part of an ethereal extract of the leaves ofBetula costata four triterpenoids of the dammarane series have been isolated. For the previously unknown triterpenoids A and C the structures of dammar-24-ene-3α,17α,20-triol and of betulafoliene-tetraol oxide, respectively, have been proposed.     

Cyclic lipopeptides with fungicidal activityfrom the sea isolate of the bacterium Bacillus subtilis

A mixture of cyclic lipopeptides with fungicidal activity was extracted from the sea isolate of the bacterium Bacillus subtilis (KMM 457). HPLC separation gave two main individual peptides of this mixture (M = 1030 and 1044 Da). According to amino acid analysis and ¹H and ¹³C NMR data, they belong to iturin antibiotics and are cyclic systems composed of the same seven -amino acids (2 Asn, Glu, Tyr, Pro, Thr, and Ser) and one -amino acid (3-aminotetradecanoic or 3-amino-13-methyltetradecanoic acid, respectively). The sequence of amino acids in these peptides was determined for the first time using tandem electrospray ionization mass spectrometry.     

A bioglycan from the gastropod mollusc Rapana thomasiana

A bioglycan — rapanan — has been isolated from the mantle of the gastropod molluscRapana thomasiana, the main carbohydrate chain of which is constructed of -(1 4)-bound D-glucose residues with a small number of side chains attached by -(1 6)-glucosidic bonds to the main chain of the bioglycan.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 25–28, January–February, 1986.