Crystal and molecular structure of salvicin — A diterpenoid acid of the clerodane series

The spatial structure of the diterpenoid salvicin has been determined by x-ray structural analysis. The trans-linkage of rings A/B proposed previously has been confirmed. This indicates that rings A and B in related diterpenoids — salvin and salvinin — also have the trans-linkage.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 63–68, January–February, 1988.     

The x-ray structural investigation of alkaloids I. Molecular structure and absolute configuration of (+)-cocculine

Summary An x-ray structural investigation of the alkaloid (+)-cocculine in the form of the hydrobromide has been performed. The bond lengths and valence angles are the usual ones. The conformations of the rings are: A — envelope⁴E; B — half-chair⁹T₅; C — half-chair¹⁰H₅. The absolute configuration 3R,5S has been established.Institute of Heteroorganic Compounds, Academy of Sciences of the USSR. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 395–400, May–June, 1975.     

Crystalline and molecular structures of the alkaloid delcosine

The molecular and crystalline structures of the diterpene alkaloid delcosine (iliensine) have been investigated by x-ray structural analysis. It has been confirmed that the OH group in ring A is located at C(1) and has the orientation. The rings in the molecule have the following conformations: A, B, and D — boat; C and F — envelope; E — chain. The ring linkages are: A/B — trans; A/E — cis; B/C — cis; B/D — cis; B/F — cis. The conformations and linkages of the rings are identical with those observed in lycoctonine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 754–758, November–December, 1983.     

Minor diterpenoids of Teucrium chamaedrys

Summary The structures of four new diternenoids ofTeucrium chamaedrys L.—teucrins B, E, F, and G, be-longing to the group of rearranged labdanes — has been shown. For teucrins E and F, the trans-(5, 10)-linkage of rings A/B has been shown.Institute of Chemistry, Academy of Sciences of the Moldavian SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 589–598, September–October, 1974.     

Phospholipid and fatty acid composition of Echinodermata. I. ClassOphiuroidea

The phospholipid compositions of five species of marine ophiuroids belonging to the classOphiuroidea have been investigated. It has been shown that the phosphatidylethanolamines contain almost solely ether bonds in the first position of the glycerophospholipids. The amount of the plasmalogen form in the phosphatidylethanolamines averages 89.8% (82.3–96.2%) and the amount of the alkyl form 9.8% (3.8–17.7%). The compositions of the fatty acids, fatty aldehydes, and alkyl ethers in the two main classes of phospholipids — phosphatidylethanolamine and phosphatidylcholine — have been studied. The main acids found were eicosatetraenoic and eicosapentaenoic, the total amount of which was 53%. It has been shown that the ophiuroids can be used as promising objects for the investigation of the metabolism of alkoxylipids and for their preparative isolation.Volga Basin Ecological Institute of the USSR Academy of Sciences, Tol'yatti. Translated from Khimya Prirodnykh Soedinenii, No. 5, pp. 547–551, September–October, 1986.     

Calculations of silicooxygen ring vibration frequencies

In the work model calculations of the vibrations of ideally isolated silicooxygen rings (using PM3 method) have been carried out. three-, four-, and six-membered rings have been considered. It has been found that that the three-membered silicooxygen rings are flat and practically undeformed showing D_3h symmetry. The rings of higher number of ring members (i.e. n>3) are deformed to some extent. The deformation reveals itself most significantly in the Si–O–Si bond angles distribution. In the case of all the rings the bridging Si–O–Si bonds are ca. 0.02–0.04 Å shorter than the non-bridging Si–O⁻ bonds. Hypothetical IR spectra for all the rings considered have been also calculated. Analysis of these hypothetical spectra leads to the conclusion that the whole spectrum can be divided into four wavenumbers regions, 1200–1100 cm⁻¹ stretching Si–O(Si) vibrations; 1000–800 cm⁻¹ stretching Si–O⁻ vibrations; 800–600 cm⁻¹; the region in which a band characteristic of silicooxygen rings appears, and below 600 cm⁻¹ bending ⁻O–Si–O⁻ and (Si)O–Si–O(Si). It has been also found that as the number of ring members increases the ‘ring band’ shifts to lower wavenumbers: 725 cm⁻¹ for three-membered rings, 650 cm⁻¹ for four-membered rings and 610 cm⁻¹ for six-membered rings. Calculated spectra have been compared with the experimental spectra of cyclosilicates. They showed good agreement in the 1200–600 cm⁻¹ region. In the experimental spectra as well as in the calculated ones, with increasing the number of ring members the ‘ring band’ shifts towards lower wavenumbers.     

Competitive bindings of histones with DNA in formation of plant nucleohistones

An acid form of ricin — ricin T — with a molecular weight of 58 kDa, an isoelectric point, pI, of 7.0–7.1, and a sedimentation coefficient of 4.60 S has been isolated from the seeds of the Central Asian castor-oil plantRicinus communis by gel filtration on Sephadex G-75 followed by ion exchange chromatography on DEAE- and CM-celluloses. The amino acid composition and the N-terminal amino acid residues of ricin T have been determined.Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 883–887, November–December, 1987.     

Reaction of tetranitrodibenzo-18-crown-6 with sodium alkoxides

It is shown that the reaction of tetranitrodibenzo-18-crown-6 with sodium alkoxides in aprotic solvents at room temperature occurs with initial cleavage of the macroheterocycle and formation of an intermediate — substituted o-dinitrobenzene — whereas the reaction in protonated solvents occurs with substitution of the nitro groups. From among other derivatives of dibenzo-18-crown-6 containing azole rings linked to the benzene ring, only the furoxan-containing crown ether is cleaved under similar conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 37–40, January, 1989.     

Extractive substances of the bark of Picea obovata

The chemical composition of a petroleum ether extract of the bark of the Siberian spruce has been studied. Extracts included saturated aliphatic alcohols and C₁₆-C₂₄ acids — abietic, dehydroabietic, isopimaric, oleic, lineolic, and linolenic — alkyl ferulates, ketones, and alcohols of the serratene type, and also ⁴-stigmasten-3-one. Onoceradienedione and onoceradienediol — precursors of the serratene triterpenoids — and also a saturated vicinal diol — triacontane-10,11-diol — have been isolated from the extractive substances of conifer in the native form for the first time.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 654–662, November–December, 1992.