Sarverogenin,vermutliche Struktur. Glykoside und Aglykone, 314. Mitteilung

Sarverogenin is most probably a 3β, 11β, 14β-trihydroxy-7, 8β-epoxy-12-oxo-5β-card-(20:22)-enolide ( 3 ). This follows from IR., NMR., and mass spectra together with former chemical results.     

Die vermutliche Struktur der Anodendroside. Glykoside und Aglykone, 331. Mitteilung

Five crystalline compounds (anodendrosides) have been isolated from Anodendron paniculatum (Roxb.)A. DC. (Apocynaceae). They represent glycosides containing unusual sugars. Tentative structures for anodendroside-A ( 155 ), ?E₁ ( 3 ), ?E₂ ( 84 ), ?F ( 144 ) and ?G ( 115 ) are now presented. These structures are based on UV., IR., but mostly on high resolution mass spectra. NMR.-spectra could be performed with A, O-acetyl-E₂ and O-acetyl-G, which are in good agreement with the suggested structures. The unusual methylendioxy group postulated in the sugar moiety of A, E₁ and E₂ was also established by chemical methods, yielding approximately 1 Mol. equiv. of formaldehyde after acid hydrolysis of anodendroside-E₂.     

Gymnemagenin,vermutliche struktur Glykoside und Aglykone, 289. Mitteilung

Gymnemagenin, the aglycone obtained from gymnemic acid by fermentative degradation and alkaline hydrolysis, is probably a new hexahydroxy-triterpene. The proposed structures are derived mainly from data obtained by physical methods. Gymnemagenin is probably a 3β,15α(or 16β), 21β,22α,23,28- or 3β,15α,16β,21β(or 22α), 23,28-hexahydroxy-olean-12-ene. Further experimental information is necessary for decision concerning the correct structure.     

Opposid,vermutliche Struktur. Glykoside und Aglykone, 302. Mitt.

The hypothetical structure 1 is proposed for opposide (C₂₉H₄₄O₁₁), a new glycoside from the seeds of Acokanthera oppositifolia (LAM.) CODD. Opposide is derived from the new aglycone gratogenin, which is most probably the 1β, 3β, 5β, 11α, 14β-pentahydroxy-card-20:22-enolide ( 8 ) (C₂₃H₃₄O₇) and which is bound glycosidically through position 3 to the α-pyranosidic form of 6-desoxy-L-talose. The hydrolysis of opposide by HCl in acetone gave an anhydrogenin (C₂₃H₃₂O₆) instead of the intact aglycone. In analogy to the reaction sequence observed by VOLPP and TAMM for ouabagenin, the structure of the anhydrogenin is deduced to be that of a 3β, 5β, 14β-trihydroxy-1α, 11α-epoxy-card-20:22-enolide ( 6 ). The above mentioned structures are based on the course of acetylation and especially on NMR.-spectra.     

Gymnemagenin,Struktur und O-Isopropylidenderivate Glykoside und Aglykone. 313. Mitteilung

Several O-isopropylidene derivatives of gymnemagenin ( 5 ), a hexahydroxytriterpene from the leaves of Gymnema sylvestre R. Br. have been prepared, which may perhaps be useful to correlate gymnemagenin with other triterpenes. From the data obtained we conclude that gymnemagenin is 3β, 16β, 21β, 22α, 23, 28-hexahydroxy-olean-12-ene.     

Die Glykoside Vincetoxicum hirundinaria MEDIKUS. 3. Mitteilung: Struktur von Hirundigenin und Anhydrohirundigenin. Glykoside und Aglykone, 318. Mitteilung

Hirundigenin can easily be converted into anhydrohirundigenin by thermal dehydration. Both substances are stable to alkali but unstable under acid conditions. Dehydrogenation of anhydrohirundigenin, using selenium at 310°, gave a mixture of 2-methylphenanthrene ( 29 ), 1, 2-dimethyl-phenanthro [1,2-b] furan ( 30 ) and 1-ethyl-2-methyl-phenanthro [1,2-b] furan ( 32 ), all of which could be isolated in crystalline form. The last two substances are new and their structures were confirmed by synthesis. Through these results, as well as by further reactions and spectra, it could be shown that hirundigenin and anhydrohirundigenin are 16-methyl-15-oxapregnane derivatives, further, that they have two epoxide rings and that they probably have the structures 7 and 11. These structures were proved by O. Kennard et. al. through X-ray studies of p-bromobenzoyl-anhydrohirundigenin ( 13 ). As far as we know, 15-oxasteroids had not yet been found in nature.     

Die Struktur der Drevogenine. 2. Mitteilung Struktur von Drevogenin P. Glykoside und Aglykone, 278. Mitteilung

Drevogenin A was converted in several steps (acetylation, hydrogenation, dehydration, hydrogenation, the haloform reaction and energetic alkaline hydrolysis) into 3β, 11α, 12β-trihydroxy-5α-etianic acid, which could be characterised by its crystalline methyl ester ( 15 ) and its tri-O-acetyl methyl ester ( 16 ). The same acid was obtained by partial synthesis starting from hecogenin. Taking into consideration earlier results [1], the structure of drevogenin P is proved to be 3β, 11α, 12β, 14β-tetrahydroxy-20-oxo-Δ⁵-pregnene ( 7 ). Energetic hydrolysis of dihydro-3-O-acetyldrevogenin A gave a mixture of 17αH- and 17βH-desacyl-kondurangogenin A, which were obtained in crystalline form after separation by chromatography. The only difference between the basic structures of the drevogenins and kondurangogenin A is the presence of a double bond in the 5-position in the former.     

Die Struktur der Drevogenine. 3. Mitteilung Struktur von Drevogenin A,B und D. Glykoside und Aglykone, 279. Mitteilung

The treatment of drevogenin P with isovaleryl chloride in pyridine gave an amorphous 3,12-di-O-isovaleryl-drevogenin P ( 4 ), which, on energetic acetylation, was converted into 3-O-isovaleryl-drevogenin A ( 5 ). This could be isolated in crystalline form and was converted through mild alkaline hydrolysis into drevogenin A. Hence drevogenin A could be classified as 11-O-acetyl-12-O-isovaleryl-drevogenin P. Indirectly, the structure of drevogenin B could be deduced to be most probably that of 11α-mono-O-acetyl-drevogenin P. Some details of the earlier given structures [1] are corrected here. Drevogenin D has an 11α-hydroxyl group.     

Alloglaucotoxigenin,Strukturbestimmung Glykoside und Aglykone, 280. Mitteilung

The structure of alloglaucotoxigenin is shown to be that of 3β, 14β, 15β-trihydroxy-19-oxo-5α-carda-20:22-enolide (IV) in the following way: The 19-oxo group could be eliminated by reduction of the corresponding mercaptal. The structure of the resulting 3β, 14β, 15β-trihydroxy-5α-carda-20:22-enolide, obtained in the acetylated form, was established through degradation and through partial synthesis by treatment of Δ¹⁴-anhydro-uzarigenin (XIII) with osmium tetroxide. The isomeric 3β,14α, 15α-trihydroxy-cardenolide was also formed in large quantities. The substance XI showed in its optical rotatory dispersion curve a positive, and substance XIV a negative COTTON effect.     

Adigosid,Strukturbestimmung Glykoside und Aglykone, 282. Mitteilung

This publication reports the preparative isolation of adigoside from the seeds of Nerium oleander L. with a yield of 250 mg crystalline adigoside per kilogram of seeds. Mild acid hydrolysis of adigoside gave crystalline D -diginose ( 8 ) and amorphous adigenin ( 6 ), which in turn gave a crystalline mono-O-acetyl derivative 7. With the aid of physical methods, degradative reactions and partial synthesis of 7 , the structure of adigenin was proved to be that of 16-O-isovaleryl-gitoxigenin. On the basis of molecular rotation it was shown that the sugar in adigoside ( 2 ), in accordance with the KLYNE Rule, is bound in the β-D -pyranosidic form. Adigoside showed no (or at the most very weak) digitalis type activity on the cat. This lack of activity must be due to the esterification of the 16-hydroxyl group by isovaleric acid, as it is known that an acetyl residue in the same position enhances rather than lowers the activity of 16β-hydroxy-cardenolides.     

Viminolon,Strukturbeweis. Glykoside und Aglykone, 315. Mitteilung

Reduction of di-O-benzoyl-viminolon ( 1 ) with LiAlH₄ gave a mixture of 17-isopregn-5-ene-heptols. Treatment of this mixture with NaIO₄ produced the amorphous 12-O-formyl sarcostinketone (= 12-O-formyl-3β, 8β, 12β, 14β-tetrahydroxy androst-5-en-20-one) ( 4 ). This together with former results proves the structure of 1 .     

Nigrescigenin,Identifizierung mit Sarmentosigenin A Glykoside und Aglykone, 281. Mitteilung

“Sarmentosigenin A” has been identified with nigrescigenin. The latter is the older and thus valid name for this 3β, 5β, 11α, 14β-tetrahydroxy-19-oxo-card-20:22-enolide.     

Die Glykoside der Wurzeln von Xysmalobium dilatatum WEIMARCK. 1. Mitteilung: Isolierungen. Glykoside und Aglykone, 327. Mitteilung

The roots of Xysmalobium dilatatum Weimarck contain uzarin and xysmalorin as major glycosides. The same two compounds are also present as main components in the glycoside mixture from the roots of Xysmalobium undulatum. In addition to that, X. dilatatum also contains appreciable amounts of pregnane derivatives, linked to 2-deoxy-sugars. Four such xanthydrolpositive compounds (the dilatoides A, B, C and D) have been isolated in amorphous but pure or nearly pure form; they have not been detected in the roots of X. undulatum.     

Die Cardenolide der Samen von Mansonia altissima A. CHEV. 2. Mitteilung Die Struktur von Mansonin und Strophothevosid Glykoside und Aglykone, 287. Mitteilung

Mansonin is the 2,3-di-O-methyl-6-deoxy-β-D-glucopyranoside of strophanthidin, and strophothevoside the corresponding 3-O-methyl-6-deoxy-β-D-glucopyranoside.     

Die Glykoside der Samen von Stapelia gigantea N. E. Br. Glykoside und Aglykone, 275. Mitteilung

The seeds of Stapelia gigantea are very rich in ester glycosides (ca. 5,9%). Mild acid hydrolysis gave a mixture of sugars which, after paper chromatography and electrophoresis, was found to be probably composed of cymarose, oleandrose, digitoxose, arabino-2,6-dideoxyhexose (= canarose) and pachybiose. The mixture of the raw genins gave after alkaline hydrolysis a mixture of about nine deacyl genins (C, D, E, F1, F2, F3, G, H, J); the acids split off during hydrolysis were not identified. The nine deacyl genins are probably closely related pregnane derivatives. The main component (E), C₂₁H₃₀O₄, was obtained in crystalline state, and was named stapelogenin. Its probable structure is reported in the following publication.     

Die Glykoside der Wurzeln von Xysmalobium dilatatum Weimarck. 2. Mitteilung: Teilstruktur der Dilatoside. Glykoside und Aglykone, 328. Mitteilung

The four dilatosides A, B, C and D (ester glycosides isolated from Xysmalobium dilatatum) differ from each other only in the sugar portion. They all contain the same aglycone: 12-O-acetyl-17-isolineolone (=12-O-acetyl-17-isodeacyl-cynanchogenin) ( 6 ). Its mass spectrum is discussed. In dilatoside A ( 1 ) three molecules of D -oleandrose ( 7 ) are linked to this aglycone, in dilatoside B ( 2 ) one D -canarose ( 8 ) and two oleandrose units, in dilatoside C ( 3 ) two canarose and three oleandrose, and in dilatoside D ( 4 ) probably three canarose and two oleandrose units.     

Die Struktur von Corchorosid B. Glycoside und Aglykone, 329. Mitteilung

Corchoroside B has the empirical formula C₂₉H₄₂O₈ and was found to be a L -rhammoside of canarigenin ( 5 ), most probably the α, L-rhamnopyranoside ( 1 ).     

Glykoside von Marsdenia erecta R. Br. 2. Mitteilung: Versuche zur Strukturbestimmung der Genine. Glykoside und Aglykone, 330. Mitteilung

Structures for the genins of the ester glycosides of Marsdenia erecta are suggested. They are based on the behaviour in alkaline hydrolysis of these ester glycosides, their NMR. and mass spectra and ORD. data. All genins are derived from three acyl-free pregnane derivatives, i.e. drevogenin-P ( 1 ), 17 β-marsdenin ( 3 ) and marsectohexol ( 7 ). The structure of 1 is known, 3 and 7 are new compounds, i.e. 3 = 3β,8β,11α,12β,14β-pentahydroxy-Δ⁵-pregnen-20-one and 7 = 3β,8β,11α,12β,14β,20ξ-hexahydroxy-Δ⁵-pregnene. Formulae 13–17 were attributed to the acyl-genins A-1, A-2, A-3, A-4 and A-5, but only two of them were pure compounds, i.e. acyl-genin A-3 = 11,12-di-O-tiglyl-17β-marsdenin ( 15 ) and acyl-genin A-5 = 11,12-di-O-acetyl-marsectohexoi ( 17 ). Acyl-genin A-1 is a mixture of the two esters 13a + 13b derived from drevogenin-P, and similarly acyl-genin A-2 is a mixture of the esters 14a + 14b derived from 17β-marsdenin. The poorly characterised acyl-genin A-4 is most probably a mixture of the esters 16a + 16b , also derived from 17β-marsdenin.     

Drevogenin A und Drevogenin B,zusätzlicher Strukturbeweis. Glykoside und Aglykone, 306. Mitteilung

Drevogenin B is shown to be 11-O-acetyl-drevogenin P. The earlier derived structure for drevogenin A (11-O-acetyl-drevogenin P) is further confirmed by conversion of 3-O-acetyl-drevogenin A.