Allenes and acetylens—XXIII1: Synthesis of α-allenic amines via allenic imines obtained from organocopper reactions

N-2,3-alkadienyldiphenylmethanimines 5a-h are formed in moderate yields in 1,3-substitution reactions (S_N2′) of propargylic sulfonates with an organocopper reagent derived from metalated N-methyldiphenylmethanimine 1 and Me₂S·CuBr. The imines can be readily hydrolyzed to primary α-allenic amines. Alkylation of the imines with methyl fluorosulfonate followed by hydrolysis gives N-methyl-subsituted secondary α-allenic amines.     

Automorphismen Von Cayleyalgebren Über Algebraischen Erweiterungen Endlicher KÖrper Ungerader Charakteristik

Let C denote the (split) Cayley algebra over a finite field K of odd characteristic. Given any automorphism σ of C, which is not expressible as the product of two involutory automorphisms, we show that the minimal polynomial of σ is (x ? l)(x² + x + 1)³]. This result remains true, if K is replaced by an infinite algebraic extension K′ of K. Furthermore the automorphism group of C over K′ is bireflectional iff every polynomial of degree 3 in K′[x] is reducible. This corrects and extends the results achieved by Huberta Lausch in [2].     

Analysis of trace elements in trunk wood by thick-target PIXE using dry ashing for preconcentration

Thick-target Particle Induced X-ray Emission (TTPIXE) was used for the quantitative determination of trace-element concentrations in trunk wood. The wood samples were preconcentrated by dry ashing to improve the reliability of the sampling and the sensitivity of the analytical method. Samples of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were collected from a polluted area (Harjavalta) as well as from a relatively nonpolluted area (Merimasku) in southwestern Finland. The elements studied were P, S, K, Ca, Mn, Fe, Ni, Cu, Pb, Rb, Sr, Ba, Cd and Ag. TTPIXE combined with dry ashing is a sensitive and reliable analytical technique for most elements studied. The method was validified by using several certified reference materials and also by ICP-MS analysis. Due to the low ash content (0.2–0.4%) in wood a high preconcentration factor can be obtained. Differences in trace-element uptake were observed between the two tree species studied. Trunk wood from the polluted area contained higher concentrations of heavy metal ions. Received: 30 August 1996 / Revised: 11 October 1996 / Accepted: 3 November 1996     

Regioselective syntheses, structural characterization, and electron ionization mass spectrometric behavior of regioisomeric 2,3-disubstituted 2-imino-1,3-thiazolidin-4-ones

The regioselective syntheses of 3-alkyl(aryl)-2-(anthracen-9'-ylimino)-1,3-thiazolidin-4-ones (2) and 2-alkyl(aryl)imino-3-(anthracen-9'-yl)-1,3-thiazolidin-4-ones (3) from N-(anthracen-9-yl)-N'-alkyl(aryl)thioureas were accomplished effectively using methyl bromoacetate and bromoacetyl bromide, respectively. Detailed structural characteristics were confirmed mainly by NMR techniques. The mass spectrometric behavior of the resulting sets of compounds of known structures was shown to be characteristic for each set. Some interesting fragmentation pathways involving the transfer and rearrangements of various moieties were also revealed, as well as regioisomerization for particular substituent-specific fragmentations.     

Reaktionen derd-Glucuronsäure, 2. Mitt.: Selektive Substitutionen and-Glucofuranosiduronsäurederivaten

Zusammenfassung Ausgehend von 1,2-Isopropyliden-, bzw. Methyl--d-glucofuranosiduronsäure--lacton und ihren 5-O-Benzylverbindungen konnten eine ganze Reihe verschiedener, selektiv acylierter Derivate derd-Glucofuranuronsäure erhalten werden. Von besonderem Interesse sind dabei die drei strukturell möglichen Monomesylmethyl--d-, bzw. die beiden Monomesyl-1,2-isopropyliden--d-glucofuranosiduronamide und-nitrile als wichtige Vorstufen für die Synthese verschiedener Diaminozucker. Die Ammonolyse vom 5-O-Acetyl-und 5-O-Benzoyl-d-glucofuranosiduronsäurelacton verläuft unter simultaner Acylwanderung.

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Starting from 1.2-isopropylidene-and methyl--d-glucofuranosiduronic--lactone and their respective 5-O-benzyl compounds a series of different, selectively acylated derivates ofd-glucofuranuronic acid could be obtained. Of particular interest are the three structurally possible monomesyl-methyl--d-,and the two monomesyl-1.2-isopropylidene--d-glucofuranosiduronicamides and-nitriles as important precursors for the syntheses of different diamino sugars. The ammonolysis of 5-O-acetyl-and 5-O-benzoyl-d-glucofuranosiduronic lactones proceeds with simultaneous acyl migration.

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1. Mit.::H. Weidmann, Mh. Chem.96, 766 (1965).

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DiplomarbeitD. Wewerka, Technische Hochschule Graz, 1967.     

Microwave spectrum,structure and dipole moment of cyclopentadienylberyllium hydride

Microwave spectra of C₅ H₅ BeH, C₅ H₅ BeD, ¹³CC₄ H₅ BeH, and ¹³CC₄ H₅ BeD are reported. The molecule is a C_5v symmetrical top. The BeH bond length was found to be 1.32 Å with an error limit of 0.01 Å and the CC bond length was determined as 1.423 Å with one standard deviation of 0.001 Å. The distance from the beryllium atom to the centre of the cyclopentadienyl ring, h, and the CH bond length were assumed to be 1.49 Å and 1.09 Å, respectively. The dipole moment was determined through the Stark effect to be 2.08 D with one standard deviation of 0.01 D. Four different vibrationally excited normal modes were identified and their frequencies determined by relative intensity measurements.     

The asymptotic homogenization elasticity tensor properties for composites with material discontinuities

The classical asymptotic homogenization approach for linear elastic composites with discontinuous material properties is considered as a starting point. The sharp length scale separation between the fine periodic structure and the whole material formally leads to anisotropic elastic-type balance equations on the coarse scale, where the arising fourth rank operator is to be computed solving single periodic cell problems on the fine scale. After revisiting the derivation of the problem, which here explicitly points out how the discontinuity in the individual constituents’ elastic coefficients translates into stress jump interface conditions for the cell problems, we prove that the gradient of the cell problem solution is minor symmetric and that its cell average is zero. This property holds for perfect interfaces only (i.e., when the elastic displacement is continuous across the composite’s interface) and can be used to assess the accuracy of the computed numerical solutions. These facts are further exploited, together with the individual constituents’ elastic coefficients and the specific form of the cell problems, to prove a theorem that characterizes the fourth rank operator appearing in the coarse-scale elastic-type balance equations as a composite material effective elasticity tensor. We both recover known facts, such as minor and major symmetries and positive definiteness, and establish new facts concerning the Voigt and Reuss bounds. The latter are shown for the first time without assuming any equivalence between coarse and fine-scale energies (Hill’s condition), which, in contrast to the case of representative volume elements, does not identically hold in the context of asymptotic homogenization. We conclude with instructive three-dimensional numerical simulations of a soft elastic matrix with an embedded cubic stiffer inclusion to show the profile of the physically relevant elastic moduli (Young’s and shear moduli) and Poisson’s ratio at increasing (up to 100 %) inclusion’s volume fraction, thus providing a proxy for the design of artificial elastic composites.