Triterpene glycosides ofAstragalus and their genins. XLVIII. The structures of cycloalpigenin B and cycloalpioside B

The structures of the new cycloartane methylsteroid cycloalpigenin B and its glycoside cycloalpioside B, isolated fromAstragalus alopecurus Pall. (Leguminosae) have been determined on the basis of chemical transformations with the assistance of¹H and¹³C NMR spectroscopy and 2D NMR¹H-¹H and¹H-¹³C correlations of chemical signals and IR, CD, and electron-impact mass spectrometry. Cycloalpigenin B is 20R,24S-epoxycycloartane-3,12,16,25-tetraol. A transition from cycloalpigenin B to cycloalpigenin A has been achieved. Cycloalpioside B is 20R,24S-epoxycycloartane-3,12,16,25-tetraol 3-O--D-xylopyranoside.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 515–521, July–August, 1994.     

Triterpene glycosides ofAstragalus and their genins. XLVII. Structures of cycloalpigenin A and cycloalpioside A

The structures of two new cycloartane triterpenoids, cycloalpigenin A and cycloalpioside A, isolated from Astragalus alopecurus Pall. (Leguminosae) have been established on the basis of chemical transformations together with¹H,¹³C, and 2D¹H-¹H and¹H-¹³C chemical shift correlation NMR spectroscopy and IR, mass, and CD spectra. Cycloalpigenin A is 3β,16β,25-trihydroxy-20R,24S-epoxycycloartan-12-one, and cycloalpioside A is cycloalpigenin A 3-O-β-D-xylopyranoside.     

Triterpene glycosides of Astragalus and their genins XLIV. Structure of cyclocarposides A and C

The structures of two new cycloartane glycosides — cyclocarposides A and C, isolated from the herbAstragalus coluteocarpus Boiss. — have been established on the basis of spectral characteristics and chemical transformations. Cyclocarposides A and C are: 204R,24S-epoxycycloartane-3β,6α,17β,25-tetraol 3-O-(2-O-acetyl-β-D-xylopyranoside)6-O-(2-O-acetyl-α-L-rhamnopyranoside) and 20R,24S-epoxycyloartane-3β,6α,16β,25-tetraol 3-O-(2-O-acetyl-β-D-xylopyranoside) 6-O-α-L-rhamnopyranoside, respectively.     

Iriterpene glycosides of Astragalus and their genins XLIII. Cycloaraloside B from Astragalus amarus

The structure of a new cycloartane glycoside, cycloaraloside B, isolated from the roots ofAstragalus amarus Pall. (Leguminosae) has been established on the basis of chemical transformations and spectral characteristics: it is 20R,24S-epoxycycloartane-3β,6α,16β,25-tetraol 3-O-[O-α-L-rhamnopyranosyl-(1→2)-(6-O-acetyl-β-D-glucopyranoside)].     

Triterpene glycosides ofAstragalus and their genins. XLVII. Structures of cycloalpigenin A and cycloalpioside A

The structures of two new cycloartane triterpenoids, cycloalpigenin A and cycloalpioside A, isolated from Astragalus alopecurus Pall. (Leguminosae) have been established on the basis of chemical transformations together with¹H,¹³C, and 2D¹H-¹H and¹H-¹³C chemical shift correlation NMR spectroscopy and IR, mass, and CD spectra. Cycloalpigenin A is 3,16,25-trihydroxy-20R,24S-epoxycycloartan-12-one, and cycloalpioside A is cycloalpigenin A 3-O--D-xylopyranoside.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 379–385, May–June, 1994.     

Triterpene glycosides of Astragalus and their genins XXXIV. Cycloaraloside E from Astragalus amarus

Five compounds of glycosidic nature, designated 5–9 have been isolated from the roots of the plantAstragalus amarus Pall. (Leguminosae). The structure of substance 8, which has been called cycloaraloside E, has been shown on the basis of chemical transformations and spectral characteristics. Cycloaraloside E is 20R, 24S-epoxycycloartane-3β,6α,16β,25-tetraol 3,25-di-0-β-D-glucopyranoside.     

Triterpenoids from the leaves of far eastern species of the shrubby birchesBetula ovalifolia andB. middendorfii

From the unsaponifiable fraction of an ethereal extract of the leaves ofBetula ovalifolia have been isolated the new triterpene 20(S),24(R)-epoxydammarane-3α,17α,25-triol (V) and the corresponding monoketone at C³ (VI). The leaves ofB. middendorfii have yielded the triterpene (IX) and (X), identified as, respectively, dammar-23-ene-3α,12β,20(S),25-tetraol and damman-25-ene-3α,12β,20-(S),24-tetraol, which have been obtained previously from the leaves ofBetula platyphylla Sukatchev var.japonica.     

Glycosylation of triterpenoids of the dammarane series. IX. β-D-glucopyranosides of 20(S),24(R)-epoxydammarane-3α,12β,17α,25-tetraol 25-tetraol

Glycosides have been synthesized from 20(S),24(R)-epoxy-dammarane-3α,12β,17α, 25-tetraol, which was isolated from the leaves ofBetula costata. Exhaustive glycosylation of betulafolienetetraol oxide with α-acetobromoglucose in the presence of mercury cyanide gave an acetylated 3,12,25-triglucoside (yield 61%), while glycosylation in the presence of insoluble silver compounds led to the formation of 3- and 12-mono- and 3,12- and 12,25-diglucopyranosides (total yield 57–82%). The structures of the glucosides obtained have been established on the basis of the results of IR and¹H and¹³C NMR spectroscopy.     

Triterpene Glycosides of Astragalus and Their Genins. LXVIII. Cycloorbigenin C, a New Cycloartane Genin

The new triterpenoid cycloartane cycloorbigenin C, the structure of which is 23ξ,24ξ-cycloartan-3β,6α,16β,23,24,25-hexaol, was obtained from the aerial part of Astragalus orbiculatus Ledeb. (Leguminosae). The structure of cycloorbigenin C was proved using chemical transformations, IR spectroscopy, electron-impact mass spectrometry, and PMR and ¹³C NMR spectra interpreted using J-modulation and the 2D NMR spectroscopies: ¹H-¹H COSY, TOCSY, ROESY, HSQC, and HMBC.     

Triterpene glycosides of Astragalus and their genins. XXXVIII. Cycloalpigenin D and cycloalpioside D from Astragalus alopecurus

Eight compounds of triterpenoid nature have been isolated from the epigeal parts of the plantAstragalus alopecurus Pall. (Leguminosae) and have been designated in order of increasing polarity as substance 1–8. On the basis of chemical transformations and spectral characteristics, we have established the structures of 4 and 8, which have been called cycloalpigenin D and cycloalpioside D, respectively. Cycloalpigenin D is 20R,24S-epoxycycloartane-3,7,16,25-tetraol. Cycloalpioside D is cycloalpigenin D 3-O--D-xylopyranoside.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 377–384, May–June, 1991.     

Triterpene glycosides ofAstragalus and their genins XLIX. Structures of cycloalpigenin C and cycloalpioside C

The structures of the new cycloartane triterpenoid cycloalpigenin C and its glycoside cycloalpioside C, isolated from the epigeal pan of Astragalus alopecurus Pall. (Leguminosae), have been determined. Cycloalpigenin C is 20R, 24S-epoxycycloartane-3,12,16, 25-tetraol, and cycloalpioside C is the 3-O- D-xylopyranoside of cycloalpigenin C.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 88–95, January–February, 1995. Original article submitted October 25, 1994.     

Triterpene glycosides ofAstragalus and their genins LVII. The structure of cyclopycnanthogenin

A new cycloartane methysteroid cyclopycnanthogenin, has been found in stems of the plantAstragalus pycnanthus Boriss. (Leguminosae). Its structure has been determined on the basis of IR, mass, and¹H and¹³C NMR spectra with the involvement of DEPT experiments and 2M¹H−¹H and¹H−¹³C chemical shift correlations [¹H−¹H COSY and¹H−¹³C (HMQC)] and also 2M NMR correlations of long-range¹H−¹³C interactions (HMBC). Cyclopycnanthogenin is 6α, 16β, 25-trihydroxy-20R, 24S-epoxycycloartane-3-one. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 515–518, July–August, 1998.     

Thyonosides A and B, two new saponins isolated from the holothurian Thyone aurea

The structures of two saponins, thyonosides A and B, isolated from the holothurian Thyone aurea collected in Namibia, were elucidated by 1D and 2D NMR (¹H, ¹³C, ¹H-¹H COSY, ¹H-¹H J-resolved, TOCSY, HMQC, HMBC and NOESY). The two compounds have the same aglycon but different oligosaccharidic chains. Thyonoside A has a 3-O-methyl-β-d-xylopyranosyl-(1→3)-6-O-sodium sulphate-β-d-glucopyranosyl-(1→4)-β-d-quinovopyranosyl-(1→2)-4-O-sodium sulphate-β-d-xylopyranosyl chain, and thyonoside B a 3-O-methyl-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→4)-β-d-quinovopyranosyl-(1→2)-4-O-sodium sulphate-β-d-xylopyranosyl chain. The holostane-type aglycon features an endocyclic double bond at position 7-8, a double bond at position 25-26 and a β-acetoxy group at C16.     

Transformed steroids. 123. Synthesis of 5α(H)- and 5α(OH)-6-ketosteroids with an additional 17α,20ξ-dihydroxytetrahydropyran ring E

The paper is devoted to the synthesis of 3,17α,20-trihydroxy-16β,23-epoxy-21,24-dinor-5αH-cholan-6-one and 3,5α,17α,20-tetrahydroxy-16β,23-epoxy-21,24-dinorcholan-6-one and derivatives of them. It has been shown that the reduction of 3,17α-dihydroxy-16β,23-epoxy-21,24-dinorchol-5-en-20-one with sodium tetrahydroborate and with diborane takes place stereospecifically with different spatial directivities: in the products of diborane reduction, ring E exists in the boat form, as has been shown by¹H and¹³C NMR methods. The trans linkage of rings A/B in the modified steroids has been confirmed by their circular dichroism spectra.     

Withasteroids ofPhysalis. V. A study of the1H and13C NMR spectra of the withasteroids visconolide and 28-hydroxywithaperuvin C

The PMR and¹³C NMR spectra of new withasteroids — visconolide and 28-hydroxywithaperuvin C, isolated fromPhysalis viscosa L. — have been investigated. A detailed analysis of the spectral characteristics obtained is given. For visconolide is proposed the structure of 4β,12α,17β,28-pentahydroxy-1-oxo-5β, 6β-epoxy-22R-witha-2,24-dienolide, and for 28-hydroxywithaperuvin C that of 6β,14α,17β,20R, 28-pentahydroxy-l-oxo-22R-witha-2, 4, 24-trienolide.     

Glycosylation of triterpenoids of the dammarane series. VI. 3-mono- and 3,12-di-O-β-D-glucopyranosides of pyxinol

The condensation of 20(S),24(R)-epoxydammarane-3β,12β,25-triol with α-acetobromoglucose in the presence of silver oxide, silver zeolite, and silver oxide with 4 Å molecular sieves has been studied. It has been established that the reaction takes place nonregioselectively and leads to a mixture of acetylated mono-, di-, and triglucosides with a predominance of the 3-O-mono- and 3,12-di-O-glucosides. The structures of the newly obtained 3-O-mono- and 3,12-di-O-glucosides have been established on the basis of the results of IR and¹H and¹³C NMR spectroscopy.     

Glycosides of marine invertebrates. XV. A new triterpene glycoside — Holothurin A1 — From Caribbean holothurians of the family Holothuriidae

A glycoside, holothurin A₁ has been isolated from the polar glyosidic fractions of the holothuriansH. floridana andH. grisea. The complete structure of the glycoside has been established; it is: 3β-[0-(3-0-methyl-β-D-glucopyranosyl)-(1 → 3)-0-β-D-glucopyranosyl-(1 → 4)-0-β-D-quinovopyranosyl-(1 → 2)-(4-sulfato-β-D-xylopyranosyl)oxy]holosta-9(11)-ene-12α,17α,22ξ-triol. Details of the IR and¹H and¹³C NMR spectra of the compounds obtained are given.     

Cycloascauloside b from <Emphasis Type="Italic">Astragalus caucasicus</Emphasis>

The structure of a new cycloartane glycoside isolated from leaves of Astragalus caucasicus Pall. (Leguminosae) was elucidated using chemical transformations and spectral data. Cycloascauloside B is 20R, 25-epoxy-24S-cycloartan-3β,6α,16β,24-tetraol 3-O-[α-L-rhamnopyranosyl-(1å2)]-β-D-glucopyranoside.     

Catalytic rearrangement of 1,2-orthoacetates of α-D-glucose and 20(S), 24(R)-epoxydammarane-3,12β,25-triols. I

The catalytic rearrangement of 20(S),24(R)-epoxydammarane-3,12β,25-triol 3-mono and 3,12-di(α-D-glucose 1,2-orthoacetate)s leads to the formation of the corresponding 12-mono- and 12,25-diglucosides. The anomalous regioselectivity of the catalytic rearrangements of orthoesters of 20(S),24(R)-epoxydammarane-3,12β,25-triols is evidently due to the influence of strong intramolecular hydrogen bonds. Details of the IR, PMR, and¹³C NMR spectra, and also the physicochemical constants, of the newly obtained compounds are given.     

X-ray analysis of betulafolienetetraol oxide,a triterpene isolated from Betula costata trautv.

The structure of betulafolienetetraol oxide has been established by X-ray analysis as 20(S),24(R)-epoxydammar-3-α,12β,17α,25-tetraol.