Anabsin — A new diguaianolide fromArtemisia absinthium

The new diguaianolide anabsin, C₃₀H₄₀O₇, mp 276°C (decomp.), [α]²⁵ +110° (c 1.7; acetone) has been isolated fromArtemisia absinthium L. Anabsin acetate, dehydroanabsin, and dehydroanabsin acetate have been obtained. A comparative study of the¹H and¹³C NMR spectra of anabsin, absinthin, and anabsinthin has been made. The structure of anabsin has been established and structures have been suggested for absinthin and anabsinthin. The most probable biogenesis of anabsin in plants has been put forward.     

Coumarins fromPhlojodicarpus sibiricus

Phlojodicarpin [8-(2,3-epoxy-1-hydroxy-3-methylbutyl)-7-methoxycoumarin, C₁₅H₁₆O₅, mp 143–145°C, [] _D ²⁵ -37.5°], and isophlojodicarpin [8-(1,2-epoxy-3-hydroxy-3-methylbutyl)-7-methoxycoumarin, C₁₅H₁₆O₅, mp 132–134°C, [] _D ²⁵ -102.5°] have been isolated from the epigeal part ofPhlojodicarpus sibiricus. The results of the IR, UV, PMR, and mass spectrometry of these compounds are given.Institute of Chemistry, Academy of Sciences of the Mongolian Peoples' Republic, Ulan-Bator. Irkutsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 47–49, January–February, 1981.     

Withasteroids ofPhysalis VI.1H and13C NMR spectra of withasteroids ixocarpalactone A and ixocarpanolide

The¹H and¹³C NMR spectra of two withasteroids isolated fromPhysalis ixocarpa Brot. have been studied in detail. Their spectral characteristics are discussed. A comparison of the results obtained has led to the identification of a withasteroid with the composition C₂₈H₄₀O₈, mp 291–292°C (from methanol) as ixocarpalactone A, in spite of some difference in its physical constants. The other compound, with mp 252–253°C (from methanol), had the composition C₂₈H₄₀O₆, [] _D ²⁰ +27±4°, is new and has been called ixocarpanolide. The structure of 5,20R-dihydroxy-1-oxo-6, 7-epoxy-22R-witha-2-enolide has been proposed for it.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 326–332, May–June, 1986.     

Structures of daurosides A and B — New acylated coumarin glycosides fromHaplophyllum dauricum

From the roots and epigeal parts ofHaplophyllum dauricum (L.) G. Don., new acylated courmarin glycosides have been isolated: dauroside A, C₂₃H₂₈O₁₃, mp 145–147°C (ethanol), [] _D ²² – 72.7° (methanol), and dauroside B, C₃₀H₃₂O₁₄, mp 145–150°C (methanol) [] _D ²² 0° (pyridine). Their structures have been established on the basis of chemical transformations and IR, UV, mass,¹H NMR and¹³C NMR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 142–147, March–April, 1983.     

Triterpene glycosides and their genins fromThalictrum foetidum. V. Structure of cyclofoetoside B

A new glycoside (cyclofoetoside B) (I) has been isolated from the epigeal part of the plantThalictrum foetidum L. (Ranunculaceae). On the basis of chemical transformations and with the aid of physicochemical characteristics it has been established that cyclofoetoside B is 24S-cycloartane-3, 16, 24, 25, 29-pentaol 3-O--L-arabinopyranoside 16-O-[O--L-rhamnopyranoside-(1 6)--D-glucopyranoside], C₄₇-H₈₀O₁₇, mp 194–197°C (methanol); [] _D ²⁴ +15.7 ± 2° (c 0.88; pyridine). The enzymatic hydrolysis of (I) has yielded cyclofoetigenin B (III), 24S-cycloartane-3,16,24,25,29-pentaol 16-O--D-glucopyranoside, (IV), C₃₆H₆₂O₁₀, mp 223–225°C (acetone), [] _D ²⁴ +37 ± 2° (c 0.97; methanol) and 24S-cycloartane-3,16,24,25,29-pentaol 16-O-[O--L-rhamnopyranosyl-(1 6)--D-glucopyranoside, C₄₂H₇₂O₁₄, mp 229–231°C (methanol), [] _D ³⁰ +41 ± 2° (c 0.7; methanol). Details of the IR and¹H and¹³C NMR spectra of the compounds are given.Irkutsk Institute of Organic Chemistry, Academy of Sciences of the USSR. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Trashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 341–345, May–June, 1986.     

Zinc(II) Hydration in Aqueous Solution: A Raman Spectroscopic Investigation and An ab initio Molecular Orbital Study of Zinc(II) Water Clusters

Raman spectra of aqueous Zn(II)–perchlorate solutions were measured over broad concentration (0.50–3.54 mol-L^–1) and temperature (25–120°C) ranges. The weak polarized band at 390 cm^–1 and two depolarized modes at 270 and 214 cm^–1 have been assigned to ₁(a _1g), ₂(e _g), and ₅(f _2g) of the zinc–hexaaqua ion. The infrared-active mode at 365 cm^–1 has been assigned to ₃(f _1u). The vibrational analysis of the species [Zn(OH₂) ₂ ⁺ ] was done on the basis of O _h symmetry (OH₂ as point mass). The polarized mode ₁(a _1g)-ZnO₆ has been followed over the full temperature range and band parameters (band maximum, full width at half height, and intensity) have been examined. The position of the ₁(a _1g)-ZnO₆ mode shifts only about 4 cm^–1 to lower frequencies and broadens by about 32 cm^–1 for a 95°C temperature increase. The Raman spectroscopic data suggest that the hexaaqua–Zn(II) ion is thermodynamically stable in perchlorate solution over the temperature and concentration range measured. These findings are in contrast to ZnSO₄ solutions, recently measured by one of us, where sulfate replaces a water molecule of the first hydration sphere. Ab initio geometry optimizations and frequency calculations of [Zn(OH₂) ₂ ⁺ ] were carried out at the Hartree–Fock and second-order Møller–Plesset levels of theory, using various basis sets up to 6-31 + G*. The global minimum structure of the hexaaqua–Zn(II) species corresponds with symmetry T _h. The unscaled vibrational frequencies of the [Zn(OH₂) ₂ ⁺ ] are reported. The unscaled vibrational frequencies of the ZnO₆, unit are lower than the experimental frequencies (ca. 15%), but scaling the frequencies reproduces the measured frequencies. The theoretical binding enthalpy for [Zn(OH₂) ₂ ⁺ ] was calculated and accounts for ca. 66% of the experimental single-ion hydration enthalpy for Zn(II).Ab initio geometry optimizations and frequency calculations are also reported for a [Zn(OH₂) ₂ ¹⁸ ] (Zn[6 + 12]) cluster with 6 water molecules in the first sphere and 12 in the second sphere. The global minimum corresponds with T symmetry. Calculated frequencies of the zinc [6 + 12] cluster correspond well with the observed frequencies in solution. The ₁-ZnO₆ (unscaled) mode occurs at 388 cm^–1 almost in perfect correspondence to the experimental value. The theoretical binding enthalpy for [Zn(OH₂) ₂ ¹⁸ ] was calculated and is very close to the experimental single ion-hydration enthalpy for Zn(II). The water molecules of the first sphere form strong hydrogen bonds with water molecules in the second hydration shell because of the strong polarizing effect of the Zn(II) ion. The importance of the second hydration sphere is discussed.     

Structure of the acylated flavonol glycoside haploside D

From the epigeal part ofHaplophyllum perforatum (MB.) Kar. et Kir. has been isolated the new flavonol glycoside haploside D, C₃₀H₃₂O₁₈, mp 225–228°C, [] _D ²⁰ -212° (c 0.17; CH₃OH) for which, on the basis of chemical transformations and spectral characteristics the structure of haplogenin 7-0-[6-0-acetyl-2-0--L-rhamnopyranosyl--D-glucopyranoside] has been established.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 304–307, May–June, 1981.     

Structure of fertenin

Summary The roots ofFerula tenuisecta have yielded a new ester C₂₂H₃₀O₅, mp 209–211°C, [] _D ²² +125° (c 0.8; ethanol), which has been called fertenin. On the basis of chemical transformations and spectral characteristics, a structure has been proposed for it as the 8-p-hydroxy-benzoate of fertenol — 9-epoxygermacr-5-ene-4,8-diol.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 161–164, March–April, 1979.     

Spatial structure of dimeric guanolides. Crystal and molecular structure of the diguanolide handelin

The structure of the disesquiterpene lactone handelin, in the form of the solvate with dimethyl sulfoxide C₃₂H₄₀O₈·C₂H₆OS has been established by the x-ray structural method (diffractometer, CuK radiation, 1976 reflections, direct method, R=0.102). The results of the investigation confirm the structure of handelin proposed previously on the basis of spectral studies. A comparative analysis has been made of the conformations of the rings of handelin, chrysanthelide, absinthin, anabsin, and artelein with those observed in A/B-cis,B/C-trans-linked monoguaianolides.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, Fax (3712) 62 73 48; and Tashkent Institute of Irrigation and the Mechanization of Agriculture. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 204–212, March–April, 1994.     

Triterpene glycosides of Astragalus and their genins. XX. Cycloorbigenin from Astragalus orbiculatus

A new genin — cycloorbigenin (I), C₃₀H₄₈O₅, mp 217–219°C, [] _D ²⁰ +28.3° (c 1.19; ethanol) has been obtained from a glycoside isolated from the epigeal parts of the plantAstragalus orbiculatus (Leguminosae), and on the basis of chemical transformation and spectral characteristics its structure has been established as 16,23:16,24-diepoxy-23(R),24(S)cycloartane-3,7,25-triol. The acetylation of (I) with acetic anhydride in pyridine yielded its diacetate (II), C₃₄H₅₂O₇, mp 148–150°C, [] _D ²⁰ +32.6° (c 0.92; methanol) and its triacetate (III), C₃₆H₅₄O₈, mp 137–139°C, [] _D ²⁰ +75° (c 0.4; methanol). The Jones oxidation of (I) led to a diketone (IV), C₃₀H₄₄O₅, mp 155–158°C, [] _D ²⁰ -73° (c 0.63; methanol). Details of the PMR, IR, and mass spectra are given for all the compounds.Institute of The Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 455–460, July–August, 1986.