Inhaltsstoffe des Osmanthus-Absolues. 1. Mitteilung: 2,5-Epoxy-megastigma-6,8-dien

Constituents of Osmanthus Absolute, Ist communication:2,5-Epoxy-megastigma-6,8-dienes Besides some further ionone derivatives we identified two new bicyclic oxacompounds ( 1a / 1b ) of the megastigmane type in the Osmanthus absolute. Isolation, special features of their spectral datas and synthesis starting from ethyl α-safranate are described. The synthetic pathway choosen allowed the additional identification of four substances occurring in the same natural substrate, because some synthetic by-products formed int he reaction sequence exhibited corresponding spectra and GLC. retention as the hitherto unknown components of the Osmanthus absolute.     

Inhaltsstoffe des Osmanthus-Absolues. 5. Mitteilung. (8E)-4, 7-Epoxymegastigma-5(11),8-dien

Constituents of Osmanthus absolute, 5th communication. (8 E )-4,7-Epoxymegastigma-5(11),8-diene The title compound 1 has been identified as trace constituent in Osmanthus absolute. The synthesis of 1 was performed by reaction of α-ionone-epoxide ( 4 ) with aluminum tri (isopropylate) in 2-propanol at 130°. Besides 1 we found another bicyclic ether 5 in the lower boiling part of the reaction mixture, and ten further substances with interesting structural features from the less volatile part. Formation mechanism as well as some spectral particularities are discussed in more detail.     

Inhaltsstoffe des Osmanthus-Absolues. 3. Mitteilung: Derivate der theaspirane

Constituents of Osmanthus-Absolute, 3rd communication: Derivatives of Theaspiranes Four isomeric new 7-oxo-dihydrotheaspiranes were identified in Osmanthus absolute. Their configuration was proved by synthetic correlations with racemic as well as optically active theaspiranes A and B. These two compounds also occurring in the same natural substrate were first correlated with the (?)-theaspirone A of known absolute configuration and the (+)-theaspirone B, respectively, thus giving the background for all further stereochemical relationship work. In depth studies in the ¹H- and ¹³C-NMR.-spectroscopy field including all possible and now synthetically available hydroxy derivatives of the new oxo compounds enabled us to unambiguously assign structures 1 to 4 to the natural products. Some further constituents bearing the same spirocyclic skeleton were also detected in Osmanthus absolute.     

Inhaltsstoffe des Osmanthus-Absolues. 4. Mitteilung: Megastigma-5, 7 (E), 9-trien-4-on und Megastigma-5, 8 (E)-dien-4-on

Constituents of Osmanthus Absolute, 4th Communication. Megastigma-5, 7 (E), 9-triene-4-one and Megastigma-5, 8 (E)-diene-4-one In continuation of our communications on constituents of Osmanthus absolute, we now report on the occurrence of the two title compounds 1 and 2a in this natural substrate (0.01-0.02% each). Their structures were confirmed by synthesis starting from β-ionone via the common intermediate 4-oxo-β-ionol ( 9 ). Some further minor components bearing corresponding structural features are tabulated in view of possible biogenetic pathways leading to 1 or 2a , respectively. In order to clarify the olfactory behaviour, we also synthesized some analogous derivatives in the irone series, these substances being not yet found in nature.     

Inhaltsstoffe des Osmanthus-Absolues 6. Mitteilung. (7S, 10S, 5E)- und (7R, 10S, 5E)-2,6,10-Trimethyl-7,10-epoxy-2,5,11-dodecatrien

Constituents of Osmanthus Absolute, 6th Communication. (7 S , 10 S , 5 E ) - and (7 R , 10 S , 5 E )-2,6,10-Trimethyl-7,10-epoxy-2,5,11-dodecatriene Two novel sesquiterpenoid oxides 1a and 1b from Osmanthus absolute have been identified. Their structural proof is based on pectral data and synthesis starting from the known methyl [5-methyl-5-vinyl-tetrahydrofur-1-yl] ketones ( 4a and 4b , respectively), whose configuration is well established. The thus obtained compounds 1a / 1b identical with the natural products, were accompanied by their corresponding 6-methylidene isomers 3a and 3b which could not be detected in the natural substrate.     

Über den einfluss von chlor-substituenten auf die bildungstendenz und bindungsverhältnisse des tricarbonyl(buta-1,3-dien)eisen: Tricarbonyl(2,3-dichlorbuta-1,3-dien)eisen und tricarbonyl(2-chlorbuta-1,3-dien)eisen

Frequencies of carbonyl stretching vibrations and relative yields in syntheses of tricarbonyl(2,3-dichlorobuta-1,3-diene)iron and tricarbonyl(2-chlorobuta-1,3-diene)iron are discussed with respect to possible steric effects of chloro-substituents on the formation of tricarbonyl(hexachlorobuta-1,3-diene)iron.     

Synthese von 2,7-Dioxa-isotwistan und 2,7-Dioxatwistan. Vorläufige Mitteilung

The syntheses of 2,7-dioxa-isotwistane ( 14 ), 2,7-dioxa-twistane ( 19 ), and some of their derivatives ( 6 – 13 and 15 – 18 ) are described. The twistane-skeleton was obtained by a molecular rearrangement starting from the iodo-iso-twistane compound 8 .     

Automerisierung von 1,3,5,5-Tetramethylcyclohexa-1,3-dien. Vorläufige Mitteilung

1,3,5,5-Tetramethylcyclohexa-1,3-diene, specifically deuterated in all positions except the gem.-dimethyl groups ( 11 ), was synthesized and found to undergo a rearrangement in the gas phase at 560°, which leads to a statistical distribution of the 6 hydrogen atoms to all 16 positions. This shows that the title compound ( 2 ) automerizes under these conditions and that the reaction proceeds via a series of ring openings (to 5 ) followed by degenerate [1,7]-H-shifts and rig closures (back to 2 ) rather than via [1,5]-CH₃-shifts. It is suggested that the previously studied rearrangement of 5,5-dimethylcyclohexa-1,3-diene ( 1 ) to 1,5-dimethylcyclohexa-1,3-diene ( 3 ) takes its course by the same reaction pathway.     

Isoswerosid,ein neues Secoiridoidglycosid aus den Wurzeln des Zwergholunders Sambucus ebulus L. (Caprifoliaceae). 2. Mitteilung über die Inhaltsstoffe der Zwergholunderwurzel

Isosweroside, a New Secoiridoid Glycoside from the Roots of Sambucus ebulus L. (Caprifoliaceae) The paper describes the isolation and structure elucidation of isosweroside (6-(β-D - glucopyranosyloxy)-methyl-9-vinyl-2,8-dioxabicyclo[3.3.1]non-6-en-3-one), the first Valeriana-type secoiridoid glycoside from the roots of Sambucus ebulus L. along with the two known glycosides ebuloside and morroniside.     

Inhaltsstoffe des Verbenaöls. 1. Mitteilung. Natürliches Vorkommen der Photocitrale und einiger ihrer Derivate

Natural Occurrence of Photocitrals and some of their Derivatives (Constituents of Verbena Oil, 1st communication). The analysis of natural verbena oil of authentic origin has revealed the presence of the synthetically known photocitral isomers 2a , 2b , 3 and 6 . They are accompanied by 2,5-dimethyl-2-vinyl-4-hexenal ( 7 ), several oxides 8–12 and some other constituents well known to occur in nature. A new sesquiterpene ether will be discussed in the following publication. The corresponding reduced compounds 15a , 15b and 16 of the photocitral isomers are also present in the essential oil.     

Über Oxidhydroxide des vierwertigen Mangans mit Schichtengitter 2. Mitteilung: Mangan (III)-manganat (IV)

The preparation and probable structure of managanese (III)-manganate (IV) Mn₇O₁₃, 5H₂O (a₀ = 2,84, c₀ = 7,27 Å) and manganous (II)-manganate (IV) Mn₇O₁₂, 6H₂O are described. Both consist of platelets. Digesting in diluted HNO₃ leads to γ-MnO₂ (nsutite). Manganese (III)-manganate (IV) is much less stable than the sodiummanganese (II, III)-manganate-(IV) described earlier and looses water easily when heated or in vacuo. Water loss results in breaking down of the double layer lattice, and the product is only two-dimensionally ordered, producing only prism reflections on the X ray diagramm. Heating results in a continuous transition to the two-dimensionally ordered phase, then to a finely divided and very disordered γ-MnO₂, and eventually to a finely divided and disordered β-MnO₂ (pyrolusite). The transition is topotactical so far, but further heating produces δ-Mn₂O₃ without obvious topotactical relations to the earlier products. The so-called ‘δ-MnO₂’ (birnessite) appears to be a family of finely divided and very disordered varieties of such manganates (IV) with part of the Mn³⁺ substituted by Mn⁴⁺. Since such products usually contain remarkable amounts of alkali ions, they are rather varieties of the earlier described sodiummanganese (II, III)-manganate (IV). A provisional explanation of the streaking in the electron diffractions of these manganate (IV). A provisional explanation of the streaking in the electron diffractions of these manganates (IV) is given. With respect to these results the so-called ‘δ-MnO₂’ can no longer be attributed to the true manganese dioxides.     

Photochemische Reaktionen. 88. Mitteilung [1]. Zur Photochemie des Iso-methyl-β,(E)-jonon-epoxids

Photolysis of iso-methyl-β,(E)-ionone-epoxide On n, π*-excitation (λ ≥ 347 nm) the title compound 7 isomerizes to the (Z)-enone-epoxide 8 , which yields the bicyclic alkohol 9 in a second photochemical step. The photoisomerization 8 → 9 is a further example for the influence of a methyl substituent at C(α) of an enone-chromophore on the nature of the photochemical processes. On UV. irradiation in the presence of traces of hydrochloric acid 7 gives quantitatively the furane 10 .     

Die Struktur des Harpagosids. 2. Mitteilung über Iridoide

The structure and configuration of harpagoside, a bitter principle from the roots of Harpagophytum procumbens DC, have been elucidated by degradation reactions and NMR. spectra. The hitherto uncertain position of a secondary hydroxyl group could be assigned to C-6 of the aglycone moiety. As earlier postulated, harpagoside ( 1 ) as well as its saponification product, harpagide ( 12 ), belong to a series of natural enol ethers known as iridoids.     

Inhaltsstoffe des Verbenaöls. 2. Mitteilung. Caryophyllan-2,6-β-oxid,eine neue Sesquiterpenverbindung aus dem Öl von Lippia citriodora KUNTH

Caryophyllane-2,6-β-oxide, a New Sesquiterpenoid Compound from the Oil of Lippia citriodora KUNTH . (Constituents of Verbena Oil, 2nd communication). Caryophyllane-2,6-β-oxide ( 2 ), a new sesquiterpenoid ether, was identified in Verbena oil. Configuration as well as synthesis from known Kobusone ( 10 ) are discussed together with the preparation of the corresponding caryophyllane-2,6-α-oxide ( 8 ) not occurring in the cited essential oil. Verbena oil contains also caryophyllene, isocaryophyllene, their epoxides and trace amounts of Kobusone ( 10 ).