Diterpenoide Drüsenfarbstoffe: Coleone S und T aus Plectranthus caninus ROTH(Labiatae), ein neues Diosphenol/trans-A/B-6,7-Diketon-Paar aus der Abietanreihe

Leaf-gland Pigments: Coleons S and T from Plectranthus caninus ROTH (Labiatae), New Hydroquinones of the Abietane Series with a Diosphenol/trans-A/B-6,7-Diketone Structure. Coleons S and T were isolated from the more polar fractions from extracts of the above mentioned plant. Coleon S, C₂₀H₂₆O₆, has been shown to have structure 1a , and coleon T, C₂₀H₂₆O₆, structure 2 .     

Diterpenoide Drüsenfarbstoffe aus Labiaten: 11 Coleone und Royleanone aus Coleus carnosus HASSK

Diterpenoid Leaf-Gland Pigments: 11 Coleons and Royleanones from Coleus carnosus HASSK . The above mentioned plant has been investigated for its leaf-gland pigments. The following diterpenoids have been isolated (listed according to their elution from Sephadex LH-20, SiO₂ and polyamide; in parentheses the yield of each product in g/kg dried leafs): royleanone ( 1 )/6,7-dehydroroyleanone ( 2 ) (0.004, as a mixture); 7α-acetyloxyroyleanone ( 3 , 0.009); a novel dimeric diterpene of hitherto unknown structure (0.03); horminone ( 4 , 0.08); 6β-hydroxyroyleanone ( 5 , 0.04, new as a natural product); 7α-acetyloxy-6β-hydroxyroyleanone ( 6 , 5.45); 6β, 7α-dihydroxyroyleanone ( 7 , 1.20); 7α-acetyloxy-6β, 20-dihydroxyroyleanone ( 8 , 0.046, a novel compound); coleon U ( 9 , 1.32); coleon V ( 10 , 13.84); carnosolone (6α, 11, 12-trihydroxy-6,20-epoxymethano-abieta-8, 11, 13-trien-7-one ( 11 ), 1.25, a novel compound). Therefore, this plant is one of the richest one in royleanones and coleons so far investigated by us (pure crystalline compounds 2,3%, estimated total amount > 3% of dry weight). Among the isolated compounds carnosolone ( 11 ) is of special interest being the first of a group of colourless diterpenoids from Coleus- and Plectranthus- species turning blue on TLC. Its oxydation product 12 is one of the rare 4-acyl-ortho-quinones having high reactivity and characteristic spectral properties.     

Diterpenoide Drüsenfarbstoffe aus Labiaten: 3β-Acetoxyfuerstion,Nilgherron A und Nilgherron B,neue Chinomethane aus Plectranthus nilgherricus BENTH.; absolute Konfiguration von Fuerstion

Leaf-gland Pigments: 3β-Acetoxyfuerstione, Nilgherron A and Nilgherron B, New Quinomethanes from Plectranthus nilgherricus BENTH . (Labiatae); Absolute Configuration of Fuerstione We have isolated from leaf-glands of the above mentioned plant the following deeply coloured quino-methane derivatives: (1) traces of the already known fuerstione ( 1a ); 11,15-dihydroxy-5,7,9 (11), 13-abietatetraen-12-one; (2) the new 3β-acetoxy-fuerstione ( 1b ); (3) nilgherron A ( 5a , I or II), a new dimeric diterpenoid quinomethane, C₄₀H₅₂O₇, formed in the plant obviously by cycloaddition of the o-quinone 8 (9aS, 11R)-11 -hydroxy-2-(1-hydroxy-1-methylethyl-9,9-dimethyl-3,4,7,8,9,9a,10,11- octahydro-5H-dibenzo [a, d]cycloheptene-3,4-dione) with fuerstione; (4) nilgherron B ( 5b , I or II), C₄₂H₅₄O₉, likewise a new compound, formed by the same type of cycloaddition (heterodiene synthesis) of 8 with 3β-acetoxyfuerstione. On the basis of ¹H-NMR. shift arguments structure I is slightly preferred to II for 5a and 5b . Model experiments have shown the easy formation of the dihydrodioxin ring by reaction of an o-benzoquinone with p-quinomethanes. The absolute configuration of fuerstione and 3β-acetoxyfuerstione has been determined by chiroptical methods.     

Diterpenoide Drüsenfarbstoffe aus Labiaten: Coleone U,V, W und 14-O-Formyl-coleon-V sowie 2 Royleanone aus Plectranthus myrianthus BRIQ.; cis- und trans-A/B-6, 7-Dioxoroyleanon

Leaf-gland Pigments: Coleons U, V, W, 14- O -Formyl-coleon-V, and two Royleanones from Plectranthus myrianthus BRIQ. ; cis - and trans -A/B-6,7-Dioxoroyleanones From leaf-glands of the South-African P. myrianthus (Labiatae) the following diterpenoids have been isolated and their structures established: coleon U, C₂₀H₂₆O₅ (6, 11, 12, 14-tetrahydroxy-abieta-5, 8, 11, 13-tetraene-7-one, 2a ); coleon V, C₂₀H₂₆O₅ (11, 12, 14-trihydroxy-abieta-8, 11, 13-triene-6, 7-dione, 4a ); coleon W, C₂₂H₂₈O₈ (16(or 17)-acetoxy-6, 11, 12, 14, 17 (or 16)-pentahydroxy-abieta-5, 8, 11, 13-tetraene-7-one, 6 ); 14-O-formyl-coleon-V, C₂₁H₂₆O₆ (14-formyloxy-11, 12-dihydroxy-abieta-8, 11, 13-triene-6, 7-dione, 4b ); 7α-formyloxy-6β-hydroxyroyleanone, C₂₁H₂₈O₆ (7α-formyloxy-6β, 12-dihydroxy-abieta-8, 12-diene-11, 14-dione, 1a ); the already known 6β, 7α-dihydroxyroyleanone ( 1c ) and a dimeric abietane derivative whose structure is not yet elucidated. This is the first record of a co-occurrence of coleons and royleanones in the same plant. In the course of chemical investigations of 4a and 4b the highly oxidized trans- and cis-A/B-6,7-dioxoroyleanones ( 5a and 5b ) were obtained.     

Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus Oxo-isophoron. I. Modifizierung der Kienzle-Mayer-Synthese von (3S 3′S)-Astaxanthin

Technical Procedures for the Synthesis of Carotenoids and Related Compounds from 6-Oxo-isophorone. I. Modification of the Kienzle-Mayer-Synthesis of (3S, 3′S)-Astaxanthin An efficient synthesis of (3S, 3′S)-astaxanthin ( 1a ) in high yield and optical purity starting from (4R, 6R)-4-hydroxy-2,2,6-trimethylcyclohexanone ( 4 ) is reported. The absolute configuration of 1a , previously derived from ORD. data, has been confirmed by X-ray analysis of 5 , a derivative of 6-oxo-isophorone ( 2 ). The key features of the improved synthesis are the two-step conversion of 4 to the key intermediate (4S)-2,6,6-trimethyl-4-hydroxy-2-cyclohexen-1-one ( 14 ), a new method for the partial reduction of the sterically hindered triple bond of (S)-6-hydroxy-3-(5-hydroxy-3-methyl-3-penten-1-ynyl)-2,4,4-trimethyl-2-cyclohexen-1-one ( 32 ), and Wittig olefination of the dialdehyde 1,6-dimethyl-1,3,5-octatrienedial ( 38 ) using phosphonium salt 37 with a free hydroxyl group.     

Coleone C,D, I,I′ aus einer madegassischen Plectranthus sp. nov. Interkonversion von cis- und trans-A/B-6,7-Diketoditerpenen

Coleons C, D, I, I′, obtained from a Madagascan Plectranthus sp. nov.. Interconversion of cis- and trans-A/B-6,7-Diketoditerpenes. Fairly large amounts of Coleons C and D, as well as Coleons I and I′ (3-O-formyl derivative of Coleon I) can bc isolated from the orange glands of an unclassified North Madagascan Plectranthus sp. A reversible transformation of cis- and trans-A/B-6,7-dioxo-abietane via its diosphenol has been achieved for the first time. CD.-Spectra of these compounds are presented. Hydrogenolysis of Coleon D leads to 6β,16-dihydroxy-royleanone.     

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.     

N(a)-Demethylseredamin,ein neues Alkaloid aus Rauwolfia sumatrana; absolute Konfiguration von Seredamin. 140. Mitteilung über Alkaloide

From Rauwolfia sumatrana Jack (Apocynaceae) the two new indole alkaloids serpentinine and N_(a)-demethylseredamine were isolated. By chemical and spectroscopic evidence and by correlation experiments the latter was shown to have structure 2 . the exact position of the aromatic methoxyl group was established by an investigation of the brominated derivative 12 . The aromatic ORD. Cotton effect of N_(a)-acetyl-N_(a)-demethyl-seredamine ( 5 ) and its O-acetyl derivative 4 as well as the ketone Cotton effect of purpeline ( 9 ) suggest that all the alkaloids of the seredamine group have the same absolute stereochemistry as ajmaline ( 1 ). This was confirmed by a direct chemical correlation of seredamine ( 7 ) with ajmaline.     

Mechanismus der Bildung und des Zerfalls von Amidkomplexen,I Kupfer (II) und N,N′-Diglycylpropylendiamin

The kinetics of the formation and dissociation of the copper (II) complex with N, N′-Diglycyl-propylendiamine has been studied. In the formation reaction an intermediate was observed, the structure and reactivity of which is discussed. The rate of dissociation of the complex is proportional to [H⁺]². This is explained by a rapid proton addition to one of the amino groups, followed by the slow reaction of a second proton with the coordinated amide group. The effect of acetate buffer, which increases the dissociation rate, is discussed.     

Zur Kenntnis der Indolreaktion nach Fischer,I. Thermische und Säurekatalysierte Reaktionen von N,N′-Dimethyl-N-phenyl-N′-alkenylhydrazinen

N,N′-dimethyl-N-phenyl-N′-alkenylhydrazines 9a–9f (Scheme 2) have been prepared by three different routes. These compounds yield N-methyl-indols 14a–14f (Scheme 3) upon thermolysis at 110° or upon treatment with dilute acid in anhydrous solvents at room temperature. The rate of the acid catalysed reaction varies by several orders of magnitude within the range of the examples studied. The observed structure-reactivity relationship can be rationalized as reflecting the different tendency of the alkenylhydrazines 9a–9f for protonation on carbon vs. protonation on nitrogen (Scheme 4), the nitrogen protonated tautomer undergoing a rapid charge induced [3,3]-sigmatropic rearrangement leading ultimately to indol.     

Löslichkeitskonstanten und Freie Bildungsenthalpien von Metallsulfiden, 2. Mitt.: Die Bestimmung von ΔG Tl2S aus Potential- und Löslichkeits-messungen

For the redetermination of the standard potential Tl(Hg)/ TL⁺ _(3M) at 25°C emf-measurements were performed using the cells

$$ - Tl(Hg) | Tl^ + || AgCl, Ag + $$     

Zwei weitere Iridoid-glycoside und ein Monoterpen-glycosid aus Sambucus ebulus L. (Caprifloiaceae). 3. Mitteilung über die Inhaltsstoffe der Zwergholunderwurzel

New Iridoid Glycosides and a Monoterpene Glycoside from Sambucus ebulus L. (Caprifloiaceae) From the roots of Sambucus ebulus L., two novel valeriana-type ester iridoid glycosides, 6′-O-apiosylebuloside ( 1 ) and 7,7-O-dihydroebuloside ( 3 ), along with the open-chain monoterpene glycoside 5 were isolated. Their structure elucidation is based mainly on one- and two-dimensional NMR methods. ¹H,¹H-COSY experiments permitted complete assignment of signals arising from the disaccharide unit in 1 . Biogenetically, 3 seems to represent the equivalent of loganin in the valeriana-type series of iridoid glycosides.     

Synthetische Verwendung von Epoxynitronen. I. N-(2,3-Epoxypropyliden)-cyclohexylamin-oxid,ein neues Reagens zur Synthese von α-Methyliden-γ-lactonen aus Olefinen

Synthetic Application of Epoxynitrones I. Nitrone, a New α-Methylidene-γ-lactone Annelating Reagent The N-(2, 3-epoxypropyliden)-cyclohexylamine-N-oxide/CF₃SO₃SiR₃ reagent descried in this communication opens a new and interesting entry to the versatile N-substituted N-propenylnitrosonium ions of type b (Scheme 6). One of the uses of this reagent is shown to be the synthesis of α-methylidene-γ-lactones from olefins. This new method shows similar features as the method based on 2, 3-dichloropropylidenamine-oxide/AgBF₄ originally developed for the same purpose by Petrzilka, Felix and Eschenmoser. Epoxynitrone 18 can be transformed to the positively charged heterodiene of type b (Scheme 5) using the highly electrophilic reagents CF₃SO₃SiMe₃ ( 23 ) and CF₃SO₃Si (t-Bu)Me₂ ( 24 ), respectively. Low temperature ¹H- and ¹³C-NMR. spectroscopy at ?78° showed the sole formation of the nitrone-O-silyl-ethers a (Scheme 5). Epoxid opening leading to the diene b and subsequent reactions are observed only at about ?30°. The diene b prepared in situ, adds to isolated double bonds by way of an inverse Diels-Alder reaction to afford cycloadducts of type 27 (Scheme 7). Their stable cyanoderivatives, e.g. 28 (Scheme 7), can be isolated and transformed via 31 , 44 and 54 into cis annelated α-methylidene-γ-lactones of type 55 (Scheme 11). Using trisubstituted olefins, substitution at the lower substituted olefinic C-atom competes efficiently with the cycloaddition (e.g. 34 , Scheme 8).     

Stoffwechselprodukte von Mikroorganismen. 218. Mitteilung. Versuche zur Strukturaufklärung von Niphimycin, 1. Teil. Reinigung und Charakterisierung der Niphimycine Iα und Iβ sowie Abbau mit Salpetersäure

On the Structure Elucidation of Niphimycin, Part I. Purification and Characterization of the Niphimycins Iα and Ib?; Degradation by Nitric Acid From a sample of niphimycin the pure components, niphimycin Iα and Ib?, were isolated by column chromatography and droplet counter-current chromatography. They were characterized by UV., IR., ¹H-NMR. (300 MHz) and ¹³C-NMR. spectra. A vigorous degradation of niphimycin with nitric acid, followed by esterification with diazomethane, gave a complex mixture, from which many components could be isolated and identified. Several of the degradation products were synthesized, one of them (dimethyl 2,4-dimethyladipate) in a stereospecific manner, establishing the configuration of two of the centers of chirality of niphimycin. Niphithricin was identified with copiamycin and yielded with nitric acid a degradation mixture very similar to that from niphimycin. The structures of the degradation products are in good agreement with a macrolide-type structure of niphimycin and copiamycin. Further work for structure elucidation of niphimycin and copiamycin is in progress.     

Cycloviolaxanthin (= (3S,5R,6R,3′S,5′R,6′R)-3,6:3′,6′-Diepoxy-5,6,5′,6′-tetrahydro-β,β-carotin-5,5′-diol), ein neues Carotinoid aus Paprika (Capsicum annuum)

Cycloviolaxanthin (= (3S,5R,6R,3′S,5′R,6′R)-3.6:3′,6′-Diepoxy-5,6,5′,6′-tetrahydro-β,β-carotene-5,5′-diol), a Novel Carotenoid from Red Paprika (Capsicum annuum) From red paprika (Capsicum annuum var. longum nigrum) cycloviolaxanthin was isolated as a minor carotenoid and, based on spectral data, assigned the symmetrical structure 8 .