Zur Konfiguration der Jaborosalactone, ein neuer Abbauweg für Withanolide

Tschesche, Rudolf; Annen, Klaus; Welzel, Peter

doi:10.1002/cber.19711041120

Cited by 10 publications

(7 citation statements)

References 27 publications

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“…The immunosuppressive activity of withaferin A is evident from its ability to inhibit adjuvant arthritis in rats and the graft versus host reaction in chicks (251). Similar activity was also shown by withanolide D (68). The immunosuppressive effect of Lycium substance A (5) was demonstrated by BAHRand HANSEL (252) who studied its ability to inhibit proliferation of murine spleen cell cultures.…”

Section: Biological Activity Of Withasteroidsmentioning

confidence: 61%

“…Attempts to introduce 17J3-hydroxyl group by addition of appro- References pp. [93][94][95][96][97][98][99][100][101][102][103][104][105][106] Since syntheses of various other withanolides have been discussed by GLOTTER in a recent review (J 3), the present article provides only an outline of the synthesis ofphysalolactone B (55) and withanolide D (68) in Charts 8 and 9, respectively.…”

Section: Synthesis Of Withanolidesmentioning

confidence: 99%

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Withasteroids, a Growing Group of Naturally Occurring Steroidal Lactones

Ray¹,

Gupta²

1994

Fortschritte Der Chemie Organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

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Section: Biological Activity Of Withasteroidsmentioning

confidence: 61%

Section: Synthesis Of Withanolidesmentioning

confidence: 99%

Withasteroids, a Growing Group of Naturally Occurring Steroidal Lactones

Ray¹,

Gupta²

1994

Fortschritte Der Chemie Organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

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“…Jaborosalactone U [4] had *Hand 13C-nmr data markedly different from the previous compounds but closely resembling those of trechonolide A [5] for rings A-D (10). The 13C-nmr spectra showed the presence of only two sp2 carbons which corresponded to C-2 and C-3.…”

mentioning

confidence: 62%

“…Further, three rotamers around the C-22-C-23 bond are possible in each case; thus, the twelve structures were generated and their geometry optimized by molecular modeling using the AMI semiempirical method. NOESY experiments carried out on jaborosalactone U [4], showed that at short mixing times (0.7 sec) extremely weak or no nOe cross-peaks were observed between protons over 3.0 Á apart. Under these conditions, strong cross-peaks were observed for the pairs H-28/H-23, H-21/H-23, H-28/H-22, and H-21/H-22 (Table 2).…”

mentioning

confidence: 97%

“…Chemical shifts are given in ppm downfield from TMS as internal standard, and assignments were confirmed by COSY-45, DQF COSY, and HETCOR spectra. Low-resolution eims were measured on a VG FIGURE 2. Stereoscopic views of the predominant conformer of jaborosalactone U [4] as predicted by AMI calculations and nmr data (nOe and !H-'H couplings). Trio-2 at 70 eV by direct inlet; fabms and hreims were measured on a VG ZAB-BEQQ mass spectrometer.…”

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confidence: 99%

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Novel Withanolides from Jaborosa sativa

Bonetto¹,

Gil²,

Oberti³

et al. 1995

J. Nat. Prod.

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Four new withanolides [1-4] have been isolated from the aerial parts of Jaborosa sativa. Jaborosalactones R [1], S [2], and T [3] contain a hemiketal (or ketal) ring formed between a 21-hydroxyl and a 12-ketone and the characteristic -lactone side-chain of the withanolides. Jaborosalactone U [4] possesses an epoxy-"y-lactone side-chain and was identified as the 24,25-epoxy analogue of trechonolide A [5]• Jaborosa Miers is a South American genus belonging to the Solanaceae that comprises about 23 different species which grow mainly in Argentina (1). To date, sixJaborosa spp.have been reported to contain withanolides, namely,J. integrifolia (2-4),J. leucotricha (5-7),J. bergii (8),J. odonelliana (9),J-laciniata (formerly in the genus Trechonaetes) (10), and J. magellanica (11)(12)(13)(14)). These C2S steroidal lactones have been isolated from several genera of the Solanaceae and many of these compounds exhibit interesting biological activities, such as cytotoxic, immunosuppressive, anti-inflammatory, insecticidal, and antifeedant properties (15).FromJaborosa sativa (Miers) A.T. Hunziker & G. Barbosa (Trechonaetes sativa Miers), we have isolated four new withanolides. Three of them, jaborosalactones R [1], S [2], and T [3] incorporate, in addition to the typical -lactone side-chain, a six-membered hemiketal (or ketal) ring involving what must have been originally a C-12 keto group and a C-21 hydroxyl functionality, a novel arrangement in the withanolide class of compounds. The fourth withanolide, jaborosalactone U [4} was characterized as the 24,25-epoxy analogue of trechonolide A [51 (10). The epoxy-'y-lactone side-chain found in 4 has no precedent among the withanolides, although epoxy-b-lactones (and epoxy--lactols) and unsaturated -lactones are commonly found among this group of compounds (8,13). Preliminary biological testing has shown that jaborosalactone S has strong antifeedant activity on larvae of Tenebrio molitor (R.

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Zur Hydrogenolyse einiger 6 β‐Acetoxy‐ und 6β‐Hydroxy‐Steroid‐ Δ ⁴ ‐Olefine

1973

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Die Hydrogenolyse der Verbindungen 1, 4, 8, 9 und 10 iiber einem Palladium-Katalysator lieferte ein Gcmisch der entsprechenden A4-und As-Olefine. Die Ergebnisse kiinnen so intcrpretiert werden, daIJ intermediir ein x-Allyl-Komplex auftritt, der zum A4-und zum A5-Olefin reduziert wird. Uber Platin in Eisessig ergab 8 die beiden 5P-Steroide 6 und 7. The Hydrogenolysis of Some 6P-Acetoxy-and 6P-Hydroxy-Steroid A4-OlefinsThe hydrogenolysis of the compounds 1, 4, 8, 9, and 10 with palladium as catalyst furnished a mixture of the corresponding A4-and As-olefins. The results can be rationalized by assuming the formation of an intermediate n-ally1 complex which is reduced to form the A4-and the @olefin. Hydrogenation of 8 with platinum in acetic acid gave the two 5p-steroids 6 and 7.Kurzlich gelang uns die Verknupfung von Jaborosalacton D (19) mit 20-0x0-5apregnan und damit die Konfigurationsbestimmung der Jaborosalactonele), die zur Gruppe der in den letzten Jahren in der Natur aufgefundenen (22s-Steroide mit einer Lacton-Seitenkette gehoren 1).Der Abbau von 19 verlief uber die A4-6P-Acetoxy-Verbindung 1. aus der die allylstandige Acetoxy-Gruype hydrierend entfernt wurde. Dabei entstand ein chromatographisch einheitlich erscheinendes Olefin, dessen spektroskopische Figenschaften nicht entscheiden liden, ob es sich urn die b4-Vcrbindung 2, das As-Isomere 3 oder eine Mischung beider handelte.Literaturangaben lieferten keine sicheren Hinweise, ob bei der Hydrogenolyse von 1 eine Verschiebung der Doppelbindung aus der 4in die 5-Position zu erwarten war. So fanden Dauben et al.2), daR die hydrogenolytische offnung des Lactonringes in $.&intonin uiiter Verschiebung der Doppelbindung eintritt. Andererseits wurden aus den Derivaten 1) Bisherige Arbeiten uber die Jaborosalactone: l a ) R. Tschesche, H. Schwang und G. Legler, Tetrahedron [London] 22, I121 (1966). -Ib) R. Tscheschc, H. Schwang, H.-W. Fehlhaber und G Snatzke. ebenda 22, 1125 (1966). --1~) R. Tschesche, M. Bautngarth und P. Webel, ebenda 24, 5169 (1968). -Id) G. Snatzke, H.

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Zur Konfiguration der Jaborosalactone, ein neuer Abbauweg für Withanolide

Cited by 10 publications

References 27 publications

Withasteroids, a Growing Group of Naturally Occurring Steroidal Lactones

Withasteroids, a Growing Group of Naturally Occurring Steroidal Lactones

Novel Withanolides from Jaborosa sativa

Zur Hydrogenolyse einiger 6 β‐Acetoxy‐ und 6β‐Hydroxy‐Steroid‐ Δ ⁴ ‐Olefine

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Zur Konfiguration der Jaborosalactone, ein neuer Abbauweg für Withanolide

Cited by 10 publications

References 27 publications

Withasteroids, a Growing Group of Naturally Occurring Steroidal Lactones

Withasteroids, a Growing Group of Naturally Occurring Steroidal Lactones

Novel Withanolides from Jaborosa sativa

Zur Hydrogenolyse einiger 6 β‐Acetoxy‐ und 6β‐Hydroxy‐Steroid‐ Δ 4 ‐Olefine

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Zur Hydrogenolyse einiger 6 β‐Acetoxy‐ und 6β‐Hydroxy‐Steroid‐ Δ ⁴ ‐Olefine