Gerald Wurz

Sulphur-containing amides from Glycosmis species with different antifungal activity

Leaf extracts from different Sri Lankan provenances of Glycosmis mauritiana and G. pentaphylla have been compared by HPLC analyses and tested for antifungal activity. All collections of G. pentaphylla are uniformly characterized by the known alkaloids arborine, skimmianine and arborinine, whereas the different provenances of G. mauritiana differ by displaying chemical polymorphism of different sulphur-containing amides. Three new amides, named illukumbin B, methylillukumbin B and methylillukumbin A, have been isolated and their structures are described on the basis of spectroscopic evidence. They show different antifungal activities in bioautographic tests and appear to be accumulated mainly in individuals collected from more humid and elevated habitats.

Sulfur containing cinnamides with antifungal activity from glycosmis cyanocarpa

Abstract Bioassay guided analysis of the methanolic leaf extract of Glycosmis cyanocarpa (Rutaceae) led to the isolation of a new type of sulfur containing cinnamides with antifungal activity: sinharine (cinnamic acid methylsulfidoethylamide) (2) and the corresponding N-methyl derivative methylsinharine (4). In addition, the dominating furoquinoline kokusaginine (3) together with small amounts of skimmianine (5) and the carbazole glycozolidol (1) were also isolated. A series of quinolone and quinazolone alkaloids were detected as minor components by reversed phase HPLC. The structures of 2 and 4 were elucidated by means of spectroscopic methods (IR, UV, 1H NMR, 13C NMR, MS). Temperature dependent 1H NMR and lanthanide induced shifts (LIS) established the stereochemistry of the two conformers of 4.

Sulphones derived from methylthiopropenoic acid amides from Glycosmis angustifolia

Abstract Seven new sulphones derived from methylthiopropenoic acid amides have been isolated as dominant components from the methanolic leaf extract of Glycosmis angustifolia collected in Sri Lanka. All derivatives contained substituted phenethylamine moieties with prenyloxy (dambullins) or geranyloxy groups (gerambullins) in the para -position. Additional oxidation of the geranyl side chain leads to a diol (gerambullindiol) and to ketones (methylgerambullone and methylisogerambullone). The major component, methyldambullin, exhibited moderate antifungal activity.

Different types of sulphur-containing amides from Glycosmis cf. chlorosperma

Abstract Four new sulphur containing amides have been isolated from the methanolic leaf extract of the Malayan Glycosmis chlorosperma . Their structures and

Ritigalin, a new thiocarbonic acid imide fromGlycosmis species

SummaryFrom the lipophilic leaf extracts ofGlycosmis mauritiana andG. parviflora (Rutaceae-Aurantioideae), the novel thiocarbonic acid derived imide ritigalin was isolated as major component by MPLC and TLC. The structure was elucidated by spectroscopic evidence (1H,13C NMR; MS; IR; UV).ZusammenfassungAus den lipophilen Blatt-Extrakten vonGlycosmis mauritiana undG. parviflora (Rutaceae-Aurantioideae) wurde mit MPLC und DC das neue Methylthiocarbonsäureimid Ritigalin als Hauptkomponente isoliert. Seine Struktur wurde mit spektroskopischen Methoden aufgeklärt (1H-,13C-NMR; MS, IR; UV).

Structure and Synthesis of Phenaglydon, a new Quinolone Derived Phenanthridine Alkaloid from Glycosmis cyanocarpa

Abstract A novel quinolone derived alkaloid of the phenanthridine type, phenaglydon (2), has been isolated from the lipophilic leaf extract of Glycosmis cyanocarpa (Rutaceae) together with schinifoline (1), a prenylated 2-quinolinone characterized by a diene grouping in the side chain. Both structures have been elucidated on spectroscopic evidence. In the case of phenaglydon the proposed structure has additionally been confirmed by synthesis. The co-occurrence of these alkaloids suggests close biogenetic connections between the two compounds.

Synthesis and conformational behaviour of ditosyldiaza[2.2]orthometacyclophanes

SummaryThe N,N′-ditosyl-diaza[2.2]orthometacyclophanes5a, b were synthesized from N,N-ditosyl-metaphenylenediamine by reaction with (Z)-1,4-dichlorobutene and 1,2-bis-bromomethylbenzene, respectively. Low temperature NMR studies showed that the compound5b exists as a 1:1 mixture of chair and boat form of the strained (E,Z)-diazanonadiene ring. At room temperature all corresponding resonances are averaged on the NMR time scale (including all four ethylene bridge protons). Going to lower temperatures, in a first step the methylene bridge inversion is frozen (giving twoexo H and twoendo H, ΔG≠ ca. 52kJmol−1). In a second step the chair and boat form can be observed separately (ΔG≠ ca. 43.5 kJ mol−1 for the chair/boat flip). The assignments were confirmed by 2D NMR experiments.ZusammenfassungDie N,N′-Ditosyl-diaza[2.2]orthometacyclophane5a, b wurden aus N,N-Ditosylmetaphenylendiamin durch Umsetzung mit (Z)-1,4-Dichlorbuten bzw. 1,2-Bisbrommethylbenzol gewonnen. Tieftemperatur-NMR-Untersuchungen ergaben, daß5b als 1:1 Mischung einer Sessel- und einer Bootkonformation des gespanntenE,Z-Diazanonadienringes vorliegt. Bei Raumtemperatur ist die zugehörige Ringinversion schnell in der NMR-Zeitskala, die entsprechenden Protonen in beiden Konformeren, auch die aller CH2-Brückenprotonen, ergeben gemittelte Signale. Bei tiefen Temperaturen wird zunächst die Inversion der Methylenbrücken eingefroren (Signale für zweiexo- und zweiendo-CH2-Protonen werden erhalten, ΔG≠ ca. 52 kJ mol−1). Bei weiterer Temperatursenkung können nach Einfrieren eines zweiten dynamischen Prozesses Sessel- und Bootkonformer anhand von getrennten Signalsätzen identifiziert werden (die freie Aktivierungsenthalpie für den zugehörigen Sessel-Boot-Flip beträgt ΔG≠ ca. 43.5 kJ mol−1). Die Zuordnung der1H- und13C-NMR-Resonanzen wurde mit Hilfe von zweidimensionalen NMR-Experimenten gesichert.

Lanthanide induced shifts of aromatic 1,2,3-trimethoxy compounds: Conformational analysis of tetrahydrofurofuran-lignans in solution

SummaryThe solution conformations of 1,4-diaryl-tetrahydro-1H,3H-furo[3,4-c]furans were determined by means of the LIS technique using a modified LIS-simulation program specially designed for the requirements of the aromatic 1,2,3-trimethoxy arrangement as a bidentate coordination site for the NMR shift reagent. The resulting geometries were confirmed by force field calculations (MM2-87) and compared with X-ray derived structures. Reliable data for the conformations in solution allowed a quantitative estimation of the circular dichroism based on the coupled oscillator model.ZusammenfassungEs wurden mittels der LIS-Technik die Konformationen von 1,4-Diaryl-tetrahydro-1H,3H-furo[3,4-c]furanen in Lösung bestimmt. Dazu mußte ein modifiziertes LIS-Simulationsprogramm entworfen werden, das auf die besonderen Verhältnisse der aromatischen 1,2,3-Trimethoxy-Gruppierung eingeht, welche in den untersuchten Verbindungen als zweizähnige Koordinationsstelle für das NMR-Verschiebungsreagens fungiert. Die resultierenden Geometrien wurden mittels Kraftfeldrechnungen (MM2-87) überprüft und soweit vorhanden auch mit Röntgenstrukturdaten verglichen. Für die Lösungskonformationen wurde eine quantitative Abschätzung des Circulardichroismus auf der Basis des Modells für gekoppelte Oszillatoren durchgeführt.