Elektrodynamik der anisotropen Medien in der speziellen Relativitätstheorie

Ohne ZusammenfassungAusführlicher über die hier zu besprechende Frage wird der eine von uns a. and. O. berichten (Journ. Russ. Phys.-Chem. Gesellschaft). Nachdem diese Abhandlung schon abgeschlossen war, erfahren wir, daß Herr Prof. Frederiks (Leningrad) unabhängig von uns analoge Betrachtungen angestellt hat.     

Substitution and elimination reactions in aluminum oxide: 1-alpha- and 1-beta-benzoyloxy-delta-2-cholestene and 3-beta-chlor-delta-1-cholestene

The formerly discribed [1] unknown substance CHT 208, which was obtained as side product when 3β-benzoyloxy-Δ¹-cholestene ( 3 ) was treated with ‘neutral’ activated alumina in an unpolar solvent, has been recognized as consisting of ca. 67% 3β-hydroxy-Δ¹-cholestene ( 6 ) and of ca. 33% 3β-hydroxy-Δ¹-cholestene ( 4 ) (molecular compound 2:1). Analogous treatment of 3β-chloro-Δ¹-cholestene ( 5 ) with alumina yielded the same mixture of the allylic alcohols 4 and 6 as substitution products and of Δ^1,3-cholestadiene ( 2 ) as elimination product in equal amounts.     

Isolation and structure of the antibiotics Phomin and 5-dehydrophomin

From cultures of a Phoma species (strain S 298) (Fungi imperfecti) two new antibiotics, phomine ( 1 ) and 5-dehydrophomine ( 4 ) have been isolated. Phomine and 5-dehydrophomine represent a novel type of macrolide antibiotics, the large lactone ring being fused to a highly substituted octahydro-isoindole system. Both show cytostatic activity.     

Synthesis, structural investigation, and theoretical study of pentaf luoroethyl derivatives of [60]fullerene

Pentafluoroethyl derivatives of [60]fullerene C₆₀(C₂F₅)_n (n = 6, 8, and 10) were synthesized by the reaction of C₆₀ with C₂F₅I in glass ampoules at 380–440 °C. Isomers of composition C₆₀(C₂F₅)₆ (one isomer), C₆₀(C₂F₅)₈ (five isomers), and C₆₀(C₂F₅)10 (two isomers) were isolated by chromatographic separation. Their molecular structures were established by X-ray diffraction. The relative stabilities of isomers were compared by density functional theory calculations. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 881–887, May, 2007.     

20, 21-Azirdin-Steroide: Reaktion von Derivaten der Oxime von 5-Pregnen-20-on,9β,10α-5-Pregnen-20-on und 9β,10α-5,7-Pregnadien-20-on mit Lithiumaluminiumhydrid und von 3β-Hydroxy-5-pregnen-20-on-oxim mit Grignard-Verbindungen

20, 21-Aziridine Steroids: Reaction of Derivatives of the Oximes of 5-Pregnen-20-one, 9β, 10α-5-Pregnen-20-one and 9β, 10α-5,7-Pregnadiene-20-one with Lithium Aluminium Hydride, and of 3β-Hydroxy-5-pregnen-20-one Oxime with Grignard Reagents. Reduction of 3β-hydroxy-5-pregnen-20-one oxime ( 2 ) with LiAlH₄ in tetrahydrofuran yielded 20α-amino-5-pregnen-3β-ol ( 1 ), 20β-amino-5-pregnen-3β-ol ( 3 ), 20β, 21-imino-5-pregnen-3β-ol ( 6 ) and 20β, 21-imino-5-pregnen-3β-ol ( 9 ). The aziridines 6 and 9 were separated via the acetyl derivatives 7 and 10 . The reaction of 6 and 9 with CS₂ gave 5-(3β-hydroxy-5-androsten-17β-yl)-thiazolidine-2-thione ( 8 ). Treatment of the 20-oximes 12 and 15 of the corresponding 9β,10α(retro)-pregnane derivatives with LiAlH₄ gave the aziridines 13 and 16 , respectively. Their deamination led to the diene 14 and triene 17 , respectively. Reduction of isobutyl methyl ketone-oxime with LiAlH₄ in tetrahydrofuran yielded 2-amino-4-methyl-pentane ( 19 ) as main product, 1, 2-imino-4-methyl-pentane ( 22 ) as second product and the epimeric 2,3-imino-4-methyl-pentanes 20 and 21 as minor products. – 3β-Hydroxy-5-pregnen-20-one oxime ( 2 ) was transformed by methylmagnesium iodide in toluene to 20α, 21-imino-20-methyl-5-pregnen-3β-ol ( 23 ) and 20β, 21-imino-20-methyl-5-pregnen-3β-ol ( 26 ). Acetylation of these aziridines was accompanied by elimination reactions leading to 3β-acetoxy-20-methylidene-21-N-acetylamino-5-pregnene ( 30 ) and 3β-acetoxy-20-methyl-21-N-acetylamino-5,17-pregnadiene ( 32 ). The reaction of oxime 2 with ethylmagnesium bromide in toluene gave 20α, 21-imino-20-ethyl-5-pregnen-3β-ol ( 24 ) and 20α,21-imino-20-ethyl-5-pregnen-3β-ol ( 27 ). Acetylation of 24 and 27 led to 3β-acetoxy-20-ethylidene-21-N-acetylamino-5-pregnene ( 31 ), 3β-acetoxy-20-ethyl-21-N-acetylamino-5,17-pregnadiene 33 and 3β, 20-diacetoxy-20-ethyl-21-N-acetylamino-5-pregnene ( 37 ). With phenylmagnesium bromide in toluene the oxime 2 was transformed to 20β, 21-imino-20-phenyl-5-pregnen-3β-ol ( 25 ) and 20β,21-imino-20-phenyl-5-pregnen-3β-ol ( 28 ). Acetylation of 25 and 28 yielded 3β-acetoxy-20-phenyl-21-N-acetylamino-5, 17-pregnadiene ( 34 ) and 3β,20-diacetoxy-20-phenyl-21-N-acetylamino-5-pregnene ( 39 ). LiAlH₄-reduction of 39 gave 3β, 20-dihydroxy-20-phenyl-21-N-ethylamino-5-pregnene ( 41 ). – The 20, 21-aziridines are stable to LiAlH₄. Consequently they are no intermediates in the formation of the 20-amino derivatives obtained from the oxime 2 .     

Biosynthesis of cytochalasins. II Building blocks of cytochalasun D

A number of potential ¹⁴C- and ³H-labelled precursors were fed to growing cultures of Zygosporium masonii after the rate of formation of cytochalasin D had been measured. By chemical degradation of [¹⁴C]- and [³H, ¹⁴C]-cytochalasin D the distribution of the radioactivity originating from incorporated [4′-3H, U-¹⁴C]-L -phenylalanine and [CH₃-¹⁴C]-L -methionine was determinated. The results demonstrate that the building blocks of cytochalasin D are 1 unit of pheylalanine, 3 units of methionine and acetate units.     

Nuclear magnetic resonance spectroscopy of bufadienolides (steroidal toad poisons)

The NMR. spectra of nearly all bufadienolides (steroidal toad poisons) of known structure (aglycones and acetyl derivatives) were measured (some in various solvents) and evaluated. The results obtained allow the application of the principle of the self-consistent chemical shift values (‘rule of additivity’) for the calculation of the chemical shifts of the 18- and 19- methyl groups. The frequencies of resonance and the coupling of the protons of the 17β-pentadienolide ring and of the α-protons of the functional groups were analysed. For the determination of the NMR. spectra of polyhydroxylated bufadienolides and cardenolides d₆-dimethylsulfoxide proved to be the most suitable solvent. In this solvent not only the nature but also the relative positions of several hydroxyl groups can be recognized, the rule of additivity being also applicable. On the basis of the data recorded the position and stereochemistry of functional groups in steroidal toad poisons of unknown structure can be determined with a high degree of probability.