Über die Struktur der makrocyclischen Spermidin-Alkaloide Oncinotin,Neooncinotin und Isooncinotin. 151. Mitteilung über Alkaloide

Three spermidine alkaloids – oncinotine ( 1 ), neooncinotine ( 3 ), and isooncinotine ( 2 ) – have been isolated from the stem bark of Oncinotis nitida BENTH . (Scheme 1); 1 and 3 are so far an unseparable mixture. However, by treatment of this mixture with K-t-butoxide, neooncinotine is completely converted into isooncinotine, and oncinotine, the main alkaloid, is obtained in pure form. The structural assigment of these alkaloids is based on chemical and spectral evidence. Thus oncinotine ( 1 ) has been degraded via 24 (Scheme 4) and 32 to the putrescine derivative 35 and the piperidine derivative 34 (Scheme 5). Similarly neooncinotine ( 3 ) and isooncinotine ( 2 ), have given 34 along with the 1, 3-diaminopropane derivative 36 (Scheme 5). The major decomposition pathways of 24 , 35 and 36 in the mass spectra are described in Schemes 8, 6 and 7 respectively. The absolute configuration of 1 , 2 and 3 is derived by chiroptical correlations with (R)-(?)-N-methylconiine ( 38 ).     

Über die Wanderung der Carboxylatgruppe bei der Benzilsäureumlagerung. 26. Mitteilung über Reduktone und Tricarbonylverbindungen

The benzilic acid rearrangement of ethyl α,β-dioxo-butyrate was studied by NMR.-and UV.-techniques. In weak alkaline media (pH < 10) the ester group is hydrolyzed first, then the carboxylate group migrates to form methyltartronate. The migration of the carboxylate group was proved by radioactive labeling. At higher pH-values (pH > 11,5) the intakt ester group migrates, with ester hydrolysis occuring as a second step.     

Über die Dicyanierung der 1,4-Diaminoanthrachinone und die Reaktivität der 1,4-Diamino-9,10-dihydroanthracen-2,3-dicarbonitrile gegenüber nucleophilen Reagenzien 3. Mitteilung über Arylierungen und Heterocyclisierungen von Anthrachinonsystemen

The Dicyanation of 1,4-Diaminoanthraquinones and the Reactivity of 1,4-Diamino-9,10-dioxo-9,10-dihydroanthracene-2,3-dicarbonitriles towards Nucleophilic Reagents The reaction of 1-amino-9, 10-dioxo-4-phenylamino-9,10-dihydroanthracene-2-sulfonic acid ( 1 , R?C₆H₅) with cyanide in water yields a mixture of 1-amino-9,10-dioxo-4-phenylamino-9,10-dihydroanthracene-2-carbonitrile ( 3 , R ? C₆H₅) and 1-amino-4-(phenylamino)anthraquinone ( 4 , R ? C₆H₅) under the usual reaction conditions (Scheme 1). In dimethylsulfoxide, however, a second cyano group is introduced, and 1-amino-9,10-dioxo-4-phenylamino-9,10-dihydroanthracene-2,3-dicarbonitrile (7) is formed (Scheme 2). The cyano groups are very reactive towards nucleophiles. The cyano group in 2-position can be substituted by hydroxide and aliphatic amines (Schemes 5 and 6). The cyano group in 3-position can be eliminated by aliphatic amines and hydrazine (Scheme 7). Nucleophilic attack at the cyano C-atom of the 2-cyano group by suitable reagents leads to ring formation, yielding e.g. 2-(Δ²-1, 3-oxazolin-2-yl)-, 2-(benz[d]imidazol-2-yl)- and 2-(1H-tetrazol-5-yl)anthraquinones (Schemes 8 and 10).     

Über die relative Reaktivität von Nucleophilen. Vorläufige Mitteilung

For a number of nucleophiles L an approximate linear correlation between the logarithms of the stability constants of methylmercury-complexes of L and the nuclear spin-spin-coupling constants J of Ch₃HgL was found.     

Über die Synthese von Verbindungen mit dem Skelett der Homoproaporphine. 7. Mitteilung über natürliche und synthetische Isochinolinderivate

The synthesis of the tetracyclic spiro compounds 11, 12, 13, 14, 17, 18, 19 and 20 with homoproaporphine skeleton is described. Crucial intermediates are the secondary alcohols 10 and 16 . The structure of the spiro compounds is proved by transformation of 11 into the dihydronaphthalene derivative 24 and NMR.-spectroscopic studies of the latter.     

Synthese und ungewöhnliche Reaktivität eines Cyclotrisilans

Reductive coupling of dichlorosilane 1 with magnesium yields the stable, highly moisture sensitive cyclotrisilane 2a. The hydrolysis products, 1,3-siloxanediol 3 and disilane 4 corroborate the proposed structure of 2a. The reaction with typical silylene trapping agents like benzyl, benzophenone or 2,2′-bipyridyl results in cleavage of all three endocyclic bonds of 2a, yielding the formal silylene addition products 8, 9 and 10.     

Über die Konstitution von Loroglossin. Vorläufige Mitteilung

The Constitution of Loroglossine. Loroglossine, a characteristic constituent of orchids, is shown to be bis-[4-(β-D -glucopyranosyloxy)-benzyl]-(2 R, 3 S)-2-isobutyl-tartrate ( 1 ). Hydrolysis and esterification gave 1 mol-equiv. of dimethyl (+)-2-isobutyl-erythro-tartrate ((+)-3) and 2 mol.-equiv. of a glucoside which, after acetylation, gave 4 , identical with a synthetic sample. The erythro configuration of (+)- 3 by oxidation of isobutyl-maleic acid with osmium tetroxide and subsequent esterification. The absolute configuration of (+)- 3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 7 and 8 with S (+)- and R (?)-α-phenylbutyric acid respectively.     

Über die Struktur von geschmolzenem Selendioxid

About the Structure of Molten Selenium Dioxide The Raman spectra of molten and gaseous selenium dioxide are nearly identical. The number of bands indicates the existence of a temperature depending equilibrium of monomeric and dimeric selenium dioxide in the molten and the gaseous state. A chain structure as in the crystal could not be found. An oxygen-bridged planar ring seems most likely for the structure of the dimer. Broadening of bands two intense, polarized lines at ν = 955/966 cm^?1 indicate an equilibrium of the trans-(C_2h) with the cis-structure (C_2v).     

Über die Struktur eines neuartigen Indolalkaloids,des Talbotins. 141. Mitteilung über Alkaloide [1]

From the leaves of the African Apocynacea Pleiocarpa talbotii Wernham a novel indole alkaloid, talbotine, C₂₁H₂₄N₂O₄, has been isolated. Talbotine ( 1 ) contains a secondary N_(b)-atom and a cyclic hemiacetal group. Catalytic hydrogenation leads to 19, 20-dihydrotalbotine ( 6 ), hydrogenation in the presence of formaldehyde gives N_(b)-methyl-19, 20-dihydrotalbotine ( 8 ). In the presence of sodium methoxide and methanol, 1 is converted into the lactone 12 and the methyl ester 13 . In these reactions carbon 17 is lost as formic acid. These data, together with the analyses of the NMR. spectra of talbotine and its derivatives as well as the interpretation of the various types of the mass spectral fragmentation, lead to formula 1 for the alkaloid. Dehydrogenation of talbotine methyl ether ( 3 ) with palladium and maleic acid gives the ß-carboline derivative 26 . The N_(b)-methiodide of the latter is converted into N_(b)-methyl-talbotine methyl ether on reduction with sodium borohydride. From these data as well as from the analyses of NMR. and IR. spectra the complete relative stereochemistry of talbotine could be derived. Application of the Horeau method to the nitrogen atom b of the methyl ether 3 on the one hand and to the hydroxyl group on C17 in N_(b)-methyl-19, 20-dihydrotalbotine ( 8 ) on the other hand gives consistent results and establishes S configuration of centre 15.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 50. Eine ungewöhnliche Organolanthanverbindung

Contributions to the Chemistry of Transition Metal Alkyl Compounds. 50. A non-common Organolanthanum Compound Lanthanum reacts with dibenzyl mercury in tetrahydrofuran as a solvent with splitting of solvent molecules and with formation of ethylene and a benzyl hydrido vinyloxide lanthanum complex of the composition C₆H₅CH₂La(H)OCH?CH₂ · 2 THF. This complex, primary well soluble in tetrahydrofuran, is extremely sensitive against air and moisture and undergoes a fast coordination polymerisation with a strong decrease of the solubility. The compound was characterized by elementary analysis, the hydrolysis and deuterolysis reaction, and by the i.r. spectra.     

Über die chemische Konstitution der mit Divinylsulfon vernetzten Cellulose. 12. Mitteilung über textilchemische Untersuchungen

Cotton and viscose fibres treated with divinyl sulphone under alkaline conditions were degraded in sulphuric acid. By column chromatography degradation products have been identified which contain two glucose units on mono- and dimeric sulphone derivatives, i.e. glucose ethers of 2,2′-dihydroxyethylsulphone and of 2,2′-bis-(hydroxyethylsulphonyl)-diethylether. This is the first direct chemical proof of the existence of cross-linkages in cellulose treated with bifunctional reagents.     

Über die rolle der Aminogruppen der Faser für die Sorption von anionischen farbstoffen: Versuche mit Amino- und Hydroxypolypropylen 15. Mitteilung über textilchemische Untersuchungen [1]

(1) Three anionic mono azo dyes (Orange I, Orange II and Orange 8) and a 1:2 metal complex dye (Cibalan Grey BL) are dyed onto aminopolypropylene. With all the dyes, a Langmuir isotherm with a stoichiometric relation between the dye adsorbed and the concentration of amino groups on the substrate is obtained.