Crystal and molecular structure of 6b,7,8,8a-tetramethyl-6b,8a-dihydrocyclobut[a]acenaphthylene and 1,2,2a,10b-tetramethyl-2a,10b-dihydrocyclobuta[l]phenanthrene

The crystal and molecular structure of 6b,7,8,8a-tetramethyl-6b,8a-dihydrocyclobut[a]acenaphthylene (I) and 1,2,2a,10b-tetramethyl-2a,10b-dihydrocyclobuta[l]phenanthrene (II) is established by XRD analysis. The C(6b)-C(8a) bond in I is lengthened to 1.603(3) ∢, and the C(2a)-C(10b) bond in II is prolonged to 1.589(6) ∢. The acenaphthene and dihydrophenanthrene frameworks are planar; the rms deviations of atoms from the plane are 0.011 and 0.032 ∢, respectively. Translated fromZhurnal Strukturnoi Khimii, Vol. 38, No. 6, pp. 1140–1145, November–December, 1997.     

Generalization of dual-energy method for material identification with X-ray introscopy

X-ray nondestructive testing was used for flaw location, for examination of the content of a package, and for fault detection. However, a monoenergetic beam can determine only the density variations of the analyzed object, not its structure. Study of the structure of an object was carried out by dual-energy X-ray beams. It is established that materials have different dependences of the X-ray extinction coefficient on its energy. The possibility of determination the composition of the material using two polychromatic X-ray beams with different energy spectra is shown. A variant of the algorithm for determination of the atomic number Z in the case of a weakly absorbing material is proposed.     

Study of alkaloids of the Siberian and altai flora

A number of known allied diterpene alkaloids were isolated fromDelphinium retropilosum Sambuk, a species growing in the Altai Territory. The main one was methyllycaconitine, possessing valuable pharmacological properties. For Part 1, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 800–804, April, 1999.     

Study of alkaloids from plants of Siberia and Altai

A method forN-deethylation of diterpene alkaloids of the aconitane type by the Cope reaction was developed using conversions of lappaconitine and elatine as examples. The previously unknown nitrones ofN-deethylated lappaconitine, elatine, and elatidine were prepared.     

Study of plant coumarins 1. Transformations of peucedanin

The structure of 2-bromooreoselon, which was prepared by bromination of peucedanin or oreoselon with molecular bromine, was established. The compositions and structures of the reaction products of this bromide with amines, such as pyridine, triethylamine, and morpholine, as well as with sodium acetate and potassium hydroxide were studied. The reaction of peucedanin with m-chloroperoxybenzoic acid affords peuruthenicin isobutyrate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 362—366, February, 2006.     

Digital filtration of hydroacoustical signals in shallow water

Difference equations are derived for digital filters that compensate for the distortion introduced by multiray shallow-water hydroacoustical channels. Translated fromDinamicheskie Sistemy. Vol. 12, pp. 64–69, 1993     

Plant Coumarins. 3. (+)-PTeryxin from <Emphasis Type="Italic">Peucedanum terebinthaceum</Emphasis>

The potentially medically valuable pyranocoumarin (+)-pteryxin was isolated for the first time from Peucedanum terebinthaceum Fischer et Turcz. The structure of (+)-pteryxin was rigorously proved using mass spectrometry, NMR, IR, and UV spectroscopy and comparison of the spectral characteristics of this compound and its basic hydrolysis products (+)-cis- and (−)-trans-khellactone and angelic and acetic acids. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 468–470, September-October, 2008.     

Application of solid electrolytes α-AgI and RbAg<Subscript>4</Subscript>I<Subscript>5</Subscript> for refining phase diagrams and determining standard thermodynamic functions of compounds in silver-containing systems

Standard thermodynamic properties of minerals and phases of ternary systems Ag-Au-X (X = S, Se, Te) are determined by measuring the EMF in the cells with a common gas space and Ag₄RbI₅ as the solid electrolyte. By this means, thermodynamic functions of the following minerals and phases are determined: Au₂S, Ag₃AuS₂ (uytenbogaardtite), AgAuS (petrovskaite), Ag₂Se (naumannite), AuSe, Ag₃AuSe₂ (fischesserite), and Ag₅Te₃ (stuetzite). Thermodynamics of a pyrite-pyrrhotite equilibrium in the Ag-Fe-S system is studied in a cell with a solid electrolyte based on silver iodide at 500–730 K and atmospheric pressure.