Crystal and molecular structure of the sesquiterpene humulane alcohol juniferol

The spatial structure of the sesquiterpene humulane alcohol juniferol, which is represented in the crystal by two conformers, IA and IB, differing by the conformation of the C2...C9 section, has been established by the x-ray structural method. The strain energies of the conformers have been calculated by the method of molecular mechanics. The barrier to the interconversion of the conformers by rotation of the C2...C9 section has been calculated; it amounts to 7–8 kcal/mole. This value of the transformation barrier permits the assumption that the two conformers also exist in solution, their interconversion being hindered. Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Institute of Crystallography, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 757–762, November–December, 1990.     

Crystal and molecular structure of the sesquiterpene humulane ester juniferdin

The spatial structure of the sesquiterpene humulane ester juniferdin, isolated fromFerula juniperina, has been established by the x-ray structural method. An analysis is given of the 11-membered humulane ring in comparison with the conformation observed in fexerol and juniferol.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Institute of Crystallography, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinii, No. 4, pp. 494–499, July–August, 1991.     

Crystal and molecular structure of the sesquiterpene humulane ester juniferdin

The spatial structure of the sesquiterpene humulane ester juniferdin, isolated fromFerula juniperina, has been established by the x-ray structural method. An analysis is given of the 11-membered humulane ring in comparison with the conformation observed in fexerol and juniferol. Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Institute of Crystallography, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinii, No. 4, pp. 494–499, July–August, 1991.     

X-ray-structural investigation of sesquiterpene esters of plants of the genus Ferula. II. Crystal and molecular structure of the humulane alcohol fexerol

An x-ray structural investigation of the humulane alcohol fexerol has been carried out: diffractometer, CuK radiation, 1426 reflections, direct method, R factor 0.105. The spatial structure of the fexerol molecule has been determined. The substituents in positions 2, 5, and 8 have the orientation. The double bond in the 3–4 position has the cis configuration.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 42–46, January–February, 1986.     

Crystal and molecular structure of the sesquiterpene lactone ferulide

The spatial structure of the sesquiterpene lactone ferulide has been determined by the x-ray structural method as 2-oxo-11-senecioyl-5,6,7(H)-guaia-3,10-dien-6,12-olide. This is the first time that the sofa conformation for the cyclopentene ring had been detected in natural guaianolides.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 55–58, January–February, 1988.     

Crystal and molecular structure of the sesquiterpene lactone mucrin

An x-ray structural investigation has been made of the sesquiterpene lactone mucrin, diffractometer: Cu K radiation, 942 reflections, direct method, R factor 0.083. The spatial structure of the molecule has been determined: the lactone ring is trans-linked with the germacrane ring, the epoxide group in the 1,10 position has the 1,10-orientation, and the hydroxy group in position 6 has the -orientation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Institute of Bioorganic Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–63, January–February, 1988.     

Crystal and molecular structure of the sesquiterpene ketone 9α-hydroxymurola-4-one

Summary The crystal and molecular structure of a ketone (9-hydroxymurola-4-one) synthesized from -cadinol has been investigated. Under the conditions of its production and isolation, the ketone retains the configurations of the asymmetric centers.Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 158–161, March–April, 1979.     

Crystal and molecular structures of the sesquiterpene lactone ajafinin

An x-ray structural analysis has been made with the aim of reliably determining the spatial structure of the sesquiterpene lactone ajafinin. It has been established that it has the structure and configuration of 1,2--epoxy-3,4,10-trihydroxy-5,6(H),7(H)-guai-11(13)-en-6,12-olide.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 291–295, May–June, 1986.     

Crystal and molecular structures of the sesquiterpene lactone pyrethroidinin

The crystal structure of the sesquiterpene lactone pyrethroidinin, in the independent part of the elementary cell of which there are two molecules, has been determined by x-ray structural analysis. A stereochemical analysis is given of the results, and the structure 3,10-dihydroxy-1,6,7(H)-guaia-4(5),11(13)-dien-6,12-olide is proposed for pyrethroidinin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Institute of Bioorganic Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–55, January–February, 1988.     

Crystal structure of koraiol — A sesquiterpene alcohol with a new type of carbon skeleton from the oleoresin ofPinus koraiensis

An x-ray structural investigation has been made of a new sesquiterpene alcohol — koraiol — in the form of its complex with pyridine (2:1). The cyclobutane rings are nonplanar and the foldings of rings A and B amount to 17 and 31°, respectively. The seven-membered ring has the chair form.     

Crystal and molecular structure of isatin

A. A. Zhdanov Irkutsk State University, Institute of Applied Physics, Academy of Sciences of the Moldavian SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 29, No. 3, pp. 155–158, May–June, 1988.     

Crystal and molecular structure of sarcosine

The crystal structure of sarcosine in pure form has been determined at low temperature (135 K). The crystals are othorhombic, space group P2(1)2(1)2(1) with unit cell dimensions a = 6.687(2) A, b = 7.899(3) A, c = 8.607(3) A. On the basis of 988 reflections with intensities larger than 3 sigma (I) the structure was refined to a conventional R-factor of 0.034 to give e.s.d. in bond lengths of 0.002 A and 0.2 degrees in angles. The molecule is extended and exists in the zwitterionic form. There is a small deviation from planarity in the alpha-amino acid group as well as in the main chain.     

Crystal and molecular structure of anhydroperforine

A complete x-ray structural investigation has been made of the alkaloid anhydroperforine. The crystals are rhombic: a=17.425(5) Å, b=8.166 Å, c=11.284(5) Å, z=4, space group P2₁2₁2₁ (diffractometer, 1000 reflections, MLS in the anisotropic approximation, R=0.11). The investigation has unambiguously demonstrated the conformation of the anhydroperforine molecule and has confirmed its structure. The lengths of the bonds and the values of the valence angles are the usual ones. The conformations of rings B and C are planar, ring D has a chair, and ring A, a distorted half-chair conformation.