Hydroalumination of alkenes by the LiAlH4 · 3AlBr3 system

The hydroalumination of a series of alkenes and some fused aromatic hydrocarbons by the LiAlH₄ · 3AlBr₃ system in low-polar solvents was studied. Alkenes with mono-, di-, tri-, and tetraalkyl substituted, mono- and diaryl substituted double bonds and anthracene react at room temperature to give the corresponding dibromoaluminoalkanes in high yields. Benzylidenefluorene, tetraphenylethylene, naphthalene, and phenanthrene do not undergo hydroalumination under these conditions. Camphene, bicyclo[3.2.1]oct-2-ene, and norbornene afford the corresponding organoaluminum compounds with high stereoselectivity. Oxidation and halo- and acyldemetallation of the resulting alkyl- and arylalanes were carried out.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1637–1642, September, 1993.     

Syntheses and oxidative transformations of 6-(1-methylethylidene)-3,3a,6,6a-tetrahydro-2H-cyclopenta[b]furan-2-one and its precursors

Proceeding from the [2+2]-adduct of dichloroketene and dimethylfulvene a synthesis was developed of 6-(1-methylethylidene)-3,3a,6,6a-tetrahydro-2H-cyclopenta[b]furan-2-one, and further transformations of the latter were carried out aiming at the oxidative cleavage of the isopropylidene double bond and preparation of the corresponding cyclopentenone blocks.     

Microdetermination of thioalkyl groups

Conclusions The possibility of using a mixture of potassium iodide with orthophosphoric acid in the determination of thioalkyl groups was demonstrated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 1850–1851, October, 1966.     

Functionalization of the Allyl Fragment in (+)-δ-Cadinol

Epoxidation, bromination, and iodination of the double bond in (+)--cadinol under various conditions are accompanied by formation of 1,4- or 1,5-epoxy derivatives. By contrast, vicinal hydroxylation gives rise to normal products. Intramolecular cyclization of the resulting vicinal diols was studied.     

Prostanoids: LXXXIII. Synthesis of (±)-19-Carboxy-20-norprostaglandin F2α and Its 15β-Epimer

Starting with (±)-7-hydroxy-6-hydroxymethyl-2-oxa-cis-bicyclo[3.3.0]octan-3-one 15,-19-carboxy-20-norprostaglandins F were synthesized.     

Microdetermination of alkoxyl groups in sulfonic acid esters

Summary It was shown that the developed modification of the Zeisel-Vieböck method can be used for the microdetermination of the alkoxyl groups present in sulfonic acid esters. A mixture of potassium iodide and orthophosphoric acid is used to decompose the alkoxy compound.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimisheskaya, No. 7, pp. 1288–1289, July, 1965     

Problem of the impact interaction of an elastic rod with a Uflyand-Mindlin plate

Conclusions A problem on the impact of an elastic rod of circular cross-section onto an Uflyand-Mindlin isotropic elastic plate is considered. The radial method, which allows construction of an approximate solution behind fronts of discontinuity surfaces up to the boundary of the contact region by means of segments of power series with variable coefficients, is used as a method of solution. It is, however, established that segments of radial series are not uniformly suitable throughout the region of existence of wave motion. A method of multiple scales is used for their regularization. The method, based on asymtotics of the radial series, permits construction of a uniformly suitable expansion containing a smaller number of terms than segments of radial series, but equal to them in accuracy.Voronezh Structural Engineering Institute, Russia. Translated from Prikladnaya Mekhanika, Vol. 29, No. 2, pp. 39–46, February, 1993.     

Extraction of gold(III), palladium(II), and platinum(IV) by 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole from hydrochloric acid solutions

The extraction of gold(III), palladium(II), and platinum(IV) with 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole from hydrochloric acid solutions into toluene has been studied. The extraction follows the anion-exchange mechanism. The concentration constants and thermodynamic parameters of the extraction reaction have been calculated. The reagent is proposed for use in the extraction of the sum of precious metals.     

<Superscript>1</Superscript>H NMR study on intramolecular hydrogen bonding in 2,3-<Emphasis Type="Italic">O</Emphasis>-isopropylidene-D-ribofuranosides and their 5(4)-hydroxy derivatives

¹H NMR study showed the possibility for intramolecular hydrogen bonding in 5(4)-hydroxy derivatives of 2,3-O-isopropylidene-β-D-ribofuranose in CDCl₃. The obtained data were used to interpret differences in the ¹H NMR spectra of structurally related 5-halo-2,3-O-isopropylidene-D-ribofuranosides and four newly synthesized diastereoisomeric 5-bromo-5-deoxy-4-hydroxy-2,3-O-isopropylidene-D-ribofuranosides.