General methodology for the synthesis of conjugated dienic insect sex pheromones

A general methodology for the synthesis of various types of dienic insect sex pheromones (Z-E, E-Z, Z-Z) is based on the carbocupration of acetylene by functionalised or non-functionalised lithium dialkyl cuprates, followed by the coupling of the resulting Z dialkenyl cuprates with functionalised or non-functionalised E or Z alkenyl iodides under Pd° catalysis. The following compounds were efficiently synthesized with a high degree of stereoisomeric purity: (E-Z)7, 9-dodecadien,-l-yl acetate 1 (Lobesia botrana), (E-Z)10, 12-hexadecadien,-l-ol 2 (Bombyx mori), (Z-E)9, 11-tetradecadien,-l-yl acetate 3Spodoptera littoralis), (Z-E)5, 7-dodecadien-l-ol 4 (Malascoma disstria), (Z-Z)11, 13-Hexadecadien-l-al 5 (Amyelois transitella), (Z)9,ll-dodecadien-l-yl acetate 6 (Diparopsis castanea) and (Z-Z)9,11-tridecadien-l-yl acetate 22 (a known “pseudo-pheromone”).     

Coordination complexes of iron(III) with 3-hydroxy-2(1H)-pyridinone, 2,3-dihydroxybenzoic acid and 3,4-dihydroxybenzoic acid: preparation and characterization in the solid state

Summary The synthesis and study of a number of new iron(III) complexes of the ligands 3-hydroxy-2(1H)-pyridinone (3,2-opoH), 2,3-dihydroxybenzoic acid (2,3-dhbH₃) and 3,4-dihydroxybenzoic acid (3,4-dhbH₃) are described. These complexes have the formulae [Fe(3,2-opo)₂Cl]·PrⁿOH, K[Fe(2,3-dhbH)₂(H₂O)₂], [Fe(2,3-dhb)(H₂O)₂], K[Fe-(3,4-dhbH)₂(H₂O)₂], [Fe(3,4-dhb)(H₂O)₂] and K₆[Fe(3,4-dhb)₃]·3H₂O. The complexes were characterized by elemental analyses. X-ray powder patterns, t.g.a./d.t.g. techniques, magnetic susceptibilities and spectroscopic (u.v.-vis., i.r. and variable-temperature ⁵⁷Fe-M?ssbauer) studies. Monomeric octahedral structures are assigned for the 1∶2 2,3-dhbH²⁻ complex and the 1:3 3,4-dhb³⁻ compound. Dinuclear and/or oligonuclear structures are tentatively proposed for the remaining complexes in the solid state. In [FeL(H₂O)₂] (L³⁻ = 2,3-dhb³⁻ or 3,4-dhb³⁻), iron(III) appears to be 5-coordinate. Both oxygens of 3,2-opo⁻ participate in coordination, while the dihydroxybenzoato ligands exhibit various coordination modes, depending mainly on the positions of the hydroxy groups, their anionic charge and the ligand∶metal molar ratio used.     

Tandem asymmetric conjugate addition--silylation of enantiomerically enriched zinc enolates. Synthetic importance and mechanistic implications

[formula: see text] The zinc enolates, resulting from the copper-catalyzed enantioselective conjugate addition of dialkyl zinc reagents to cyclic and acyclic enones, could be trapped, quantitatively, as silyl enol ethers with TMSOTf in apolar solvents or with TMSCI and NEt3. These enantiomerically enriched silyl enol ethers were submitted to four synthetic transformations to show their synthetic utility. The zinc enolates obtained from acyclic enones were found to be configurationally stable, as shown by the stereochemistry of the silyl enol ethers.     

Vinly copper reagents-16. Synthesis of conjugated dienes via the addition of vinyl cuprates to acetylene

Some alkenyl cuprates add smoothly to acetylene yielding dienyl cuprates.     

Synthesis and characterization of the complexes of lanthanide(III) chlorides and nitrates with the tetradentate schiff base diethyl(ethylenebis-β-aminocrotonate)

Summary The Schiff base ligand diethyl(ethylenebis--aminocrotonate) (LH₂) reacts with lanthanide(III) chlorides and nitrates in various solvents to give solid complexes of the stoichiometriesLn(LH₂)Cl₃ (Ln=La–Yb),Ln(LH₂)₂Cl₃ (Ln=La–Sm),Ln ₂(LH₂)₃Cl₆(Ln=Eu–Yb) andLn(LH₂)(NO₃)₃ (Ln=La–Yb). Properties, conductivity measurements, X-ray powder patterns, thermal data, magnetic moments and spectroscopic (IR,¹H-NMR, electronic diffuse reflectance and solid state emission f-f spectra) are discussed in terms of the nature of the bonding and the possible structural types.

---

Synthese und Charakterisierung der Komplexe von Lanthanid(III)chloriden und -nitraten mit der vierzähnigen Schiff-Base Diethyl(ethylenbis--aminocrotonat)

Zusammenfassung Der Schiffbasen-Ligand Diethyl(ethylenbis--aminocrotonat) reagiert mit Lanthanid(III)chloriden und -nitraten in verschiedenen Lösungsmitteln unter der Bildung von festen Komplexen der StöchiometrienLn(LH₂)Cl₃ (Ln = La – Yb),Ln(LH₂)₂Cl₃ (Ln = La – Sm),Ln(LH₂)₃Cl₆ (Ln = Eu – Yb) undLn(LH₂)(NO₃)₃ (Ln = La – Yb). Die allgemeinen Eigenschaften, Leitfähigkeitsmessungen, Röntgen-Pulverdiagramme, thermische Daten, magnetische Momente und spektroskopische Daten (IR,¹H-NMR, Elektronenreflexionsspektren und Festkörperemissions-f-f-Spektren) werden im Hinblick auf die Bildungsverhältnisse im Komplex und strukturelle Möglichkeiten diskutiert.

     

Limitations of current proteomics technologies

Application of proteomics technologies in the investigation of biological systems creates new possibilities in the elucidation of biopathomechanisms and the discovery of novel drug targets and early disease markers. A proteomic analysis involves protein separation and protein identification as well as characterization of the post-translational modifications. Proteomics has been applied in the investigation of various disorders, like neurological diseases, and the application has resulted in the detection of a large number of differences in the levels and the modifications of proteins between healthy and diseased states. However, the current proteomics technologies are still under development and show certain limitations. In this article, we discuss the major drawbacks and pitfalls of proteomics we have observed in our laboratory and in particular during the application of proteomics technologies in the investigation of the brain.     

Efficient resolution of 2,2'-dihydroxy-1,1'-binaphthyl by inclusion complexation with chiral N-(3-chloro-2-hydroxypropyl)-N,N,N-trimethylammonium chloride

The complete resolution of 2,2[prime or minute]-dihydroxy-1,1[prime or minute]-binaphthyl into its enantiomers by inclusion complexation with a commercially available derivative of choline, is reported. The two enantiomers are recovered in >99% ee from the inclusion complexes by simple dissolution in a diethyl ether-water medium and the resolving agent can be recycled.     

Di-2-pyridyl ketone oxime [(py)2CNOH] in manganese carboxylate chemistry: mononuclear, dinuclear and tetranuclear complexes, and partial transformation of (py)2CNOH to the gem-diolate(2-) derivative of di-2-pyridyl ketone leading to the formation of NO3-

The use of di-2-pyridyl ketone oxime, (py)2CNOH, in manganese carboxylate chemistry has been investigated. Using a variety of synthetic routes complexes [Mn(O2CPh)2{(py)2CNOH}2].0.25H2O (1.0.25H2O), Mn4(O2CPh)2{(py)2CO2}2{(py)2CNO}2Br2].MeCN (2.MeCN), [Mn4(O2CPh)2{(py)2CO2}2{(py)2CNO}2Cl(2)].2MeCN (3.2MeCN), [Mn4(O2CMe)2{(py)2CO2}2{(py)2CNO}2Br2].2MeCN (4.2MeCN), [Mn4(O2CMe)2{(py)2CO2}2{(py)2CNO}2(NO3)2].MeCN.H2O (5.MeCN.H2O) and [Mn2(O2CCF3)2(hfac)2{(py)2CNOH}2] (6) have been isolated in good yields. Remarkable features of the reactions are the in situ transformation of an amount of (py)2CNOH to yield the coordination dianion, (py)2CO2(2-), of the gem-diol derivative of di-2-pyridyl ketone in 2-5, the coordination of nitrate ligands in 5 although the starting materials are nitrate-free and the incorporation of CF3CO2- ligands 6 in which was prepared from Mn(hfac)(2).3H2O (hfac(-)= hexafluoroacetylacetonate). Complexes 2-4 have completely analogous molecular structures. The centrosymmetric tetranuclear molecule contains two MnII and two MnIII six-coordinate ions held together by four mu-oxygen atoms from the two 3.2211 (py)2CO2(2-) ligands to give the unprecedented [MnII(mu-OR)MnIII(mu-OR)2MnIII(mu-OR)MnII]6+ core consisting of a planar zig-zag array of the four metal ions. Peripheral ligation is provided by two 2.111 (py)2CNO-, two 2.11 PhCO2- and two terminal Br- ligands. The overall molecular structure 5 of is very similar to that of 2-4 except for the X- being chelating NO3-. A tentative reaction scheme was proposed that explains the observed oxime transformation and nitrate generation. The CF3CO2- ligand is one of the decomposition products of the hfac- ligand. The two Mn(II) ions are bridged by two neutral (py)2CNOH ligands which adopt the 2.0111 coordination mode. A chelating hfac- ligand and a terminal CF3CO2- ion complete a distorted octahedral geometry at each metal ion. The CV of complex reveals irreversible reduction and oxidation processes. Variable-temperature magnetic susceptibility studies in the 2-300 K range for the representative tetranuclear clusters 2 and 4 reveal weak antiferromagnetic exchange interactions, leading to non-magnetic ST = 0 ground states. Best-fit parameters obtained by means of the program CLUMAG and applying the appropriate Hamiltonian are J(Mn(II)Mn((III))=-1.7 (2), -1.5 (4) cm(-1) and J(Mn(III)Mn(III))=-3.0 (2, 4) cm(-1).