Synthesis and some properties of gem-dichlorocyclopropane carboxaldehyde acetals and cyclopropane carboxaldehyde acetals

α,β-Unsaturated aldehyde acetals add :CCl₂ (obtained in accordance with Makosza procedure) to form gem-dichlorocyclopropanecarboxaldehyde acetals (1) in high yields when the ratio of reactants is no less than 1:4. The addition of :CCl₂ to polyunsaturated aldehyde acetals in the above conditions proceeds regioselectively at double bonds enriched by electrons. Compounds 1 are reduced by sodium in liquid ammonia to give cyclopropanecarboxaldehyde acetals (2). Both 1 and 2 are hydrolized by dilute H₃P0₄ to the corresponding aldehydes and are added to vinyl ethers in the presence of BF₃·Et₂O to produce only 1:1 adducts which are hydrolyzed by a mixture of AcOH-AcONa-H₂O to give β-formylcyclopropanes which were previously unknown.     

Untersuchungen an einigen Einkristallen des Systems CuxHg1–xCr2Se4

Study of Some Single Crystals of the Cu_xHg_1–xCr₂Se₄ System Single crystals of the Cu_xHg_1–xCr₂Se₄ for 0 ≤ x ≤ 0.077 were prepared by the chemical transport method. The crystals were analyzed and investigated by X-rays. Some electric and magnetic properties of the single crystals were determined and the results obtained are discussed.     

Application of the rotated dropping mercury electrode to the analysis of mixtures of electroactive substances

The use of poylacrylamide is recommended instead of gelatin as an ideal maximum suppressor to be employed with both the rotated dropping mercury electrode (RODE) and conventional dropping electrode (DME). It is retained at the mercury surface over the entire potential range and does not combine with heavy metals. Reproducibility of the measurement of the residual current and that of the limiting current at the RDME were studied, and it was found that accurate determinations of a single constituent (±2%) are possible at concentrations as low as 1 to 2.10^-5M. The variation of the limiting current with potential is much greater at the RDME than at the DME. This effect must be considered in the analysis of a mixture of electroactive species at the RDME. Method have been discussed for making the proper correction for a preceding wave when a limiting current of a mixture of constituents is measured. Because of its high sensitivity and good reproducibility of results, the RDME is recommended for the analysis of solutions containing one or more electroactive species at concentrations less than 10^-4M.     

Some reactions of systems containing the imidazole ring

Behavior towards sodamide is compared for 3-benzyl- and 3-methyl substituted naphth [1, 2-d] imidazole and imidazo [4, 5-f] quinoline derivatives. The following are synthesized: 2-amino derivatives of 3-benzylnaphtho- [1, 2-d] imidazole(by direct animation), and of 3-benzylimidazo [4, 5-f] quinoline (ammonolysis of a 2-chloro substituted compound).     

Synthesis and bromination of 8-methylquinoline-5-carboxylic acid

8-Methylquinoline-5-carboxylic acid was obtained by the Skraup reaction from 3-amino-p-toluic acid or by hydrolysis of 5-cyano-8-methylquinoline. The latter was synthesized by the Rosenmund-von Braun reaction from 5-bromo-8-methylquinoline, which was obtained by bromination of 8-methylquinoline in the presence of silver sulfate. Bromination in the side chain of 8-methylquinoline-5-carboxylic acid and its nitrile was studied. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 366–368, March, 1980.     

Bis(trifluoroacetoxy)iodobenzene,a new oxidant in potentiometric titrations

A new oxidimetric titrant, bis(trifluoroacetoxy)iodobenzene is proposed for potentiometric titrations in acetonitrile and water-acetonitrile media. The general analytical conditions for using this titrant and the results for the potentiometric titrations of various inorganic and organic reductants are described.     

Synthesis and Structure of Triphenylbismuth Bis(Fluorobenzoates)

The reaction between triphenylbismuth, hydrogen peroxide, and 3,4,5-trifluorobenzoic or pentafluorobenzoic acid (molar ratio 1 : 1 : 2, respectively) in ether gave triphenylbismuth bis(3,4,5-trifluorobenzoate) (I) and triphenylbismuth bis(pentafluorobenzoate) (II) in 74 and 89% yields, respectively. The structures of compounds I and II were established by X-ray diffraction. The Bi atoms have a distorted trigonal-bipyramidal coordination with acylate groups in the axial positions. The OBiO angles are 170.2(2)° and 171.5(2)° in I and II, respectively. The Bi–C(Ph)_eq bond lengths vary in the range of 2.187(6)–2.204(5) Å, the Bi–O(acyl) lengths are 2.256(5) Å in I, and 2.281(5) and 2.318(5) Å in II. In the crystals I and II, the Bi and carbonyl O atoms are involved in intramolecular interactions (Bi···O(=C) 2.926(5)–3.176(5) Å), which increase the equatorial CBiC angles on the side of these contacts to 136.2(3)° and 138.6(2)° in I and II, respectively.     

Levitation of atoms over a metal surface

The potential of the interaction of an alkali metal with a planar metal surface was calculated by solving a two-dimensional Schrödinger equation. The potential energy of the valence electron of the atom was derived from a model pseudopotential based on the image potential. It was demonstrated that the potential energy curve for the interaction of an alkali metal atom with the surface of a heavier alkali metal has a minimum at a certain distance from the surface, a feature that gives rise to equilibrium states of levitating atoms.