Molecular complexes of hydrazides with copper(II)

Summary The reaction of substituted hydrazides with copper(II) chloride was investigated in the solid state or in solution in order to account for substituent effects. Spectroscopic results and values of the formation constants indicate the occurrence of strong complexes.

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Molekulare Komplexe von Hydraziden mit Kupfer(II)

Zusammenfassung Die Reaktionen von substituierten Hydraziden mit Kupfer(II)chlorid wurden im Festzustand und in Lösung untersucht. Die spektroskopischen Ergebnisse und die Werte der Bildungskonstanten zeigen die Koordinierung zu starken Komplexen an.

     

The biosynthesis of aureothin

Feeding experiments with specifically labelled precursors show that the nitroaromatic, C-6-C-1 unit of the antibiotic aureothin (9) biologically derives by degradation of the C-6-C-3, phenylpropanoid precursor D,L-p-aminophenylalanine (1) through hydroxylation β to the nitrogen to erythro and threop-aminophenylserine (3 and 4). During the biosynthesis there is the loss of the hydrogen originally present in benzylic position in the phenylpropanoid precursor, and, further, the oxidation of the p-amino group to p-nitro takes place very late in the sequence.     

Lewis acid-promoted synthesis and reactivity of beta-O-benzylhydroxylamino imides derived from D-glyceraldehyde

This paper describes the synthesis and use of beta-hydroxylamino imides derived from D-glyceraldehyde possessing a number of reactive sites that operate synergistically or alternatively to bring about highly regio- and diastereoselective transformations to give an optically pure aziridine-2-imide, a dihydro pyrimidine-2,4-dione, or a lactone. Both the syntheses, via the diastereoselective 1,4-conjugate addition of O-benzyl hydroxylamine to alpha,beta-unsaturated imides, and transformations can be simply tuned by choosing between different Lewis acids.     

Interactions of indole derivatives with organic acceptors. III

Interactions of 1-hydroxy-2-phenylindole and 2,2-diphenyl-^3,3-bi-3H-indole with common organic acceptors are analyzed. Depending on the nature of donor-acceptor partners, the reaction may afford molecular complexes, redox products or some kind of adduct. The reaction of 1-hydroxy-2-phenylindole with tetracyanoethylene leads to the formation of 1-oxy-2-phenyl-3-(dicyanomethylidene) indole whose crystal structure is reported.Reference [9] is considered part I while part II is in press in Gazz. Chim. Ital.     

Modulated optical lattice as an atomic fabry-perot interferometer

We propose to engineer the atomic band structure in optical lattices in order to design a Fabry-Perot interferometer with large mode spacing and strong nonlinear coupling to be employed in atom optics. The use of an optical lattice allows for a significant reduction of the atomic effective mass, while the slow modulation of its parameters spatially confines the matter waves on a length scale of a few dozen optical wavelengths. As a consequence, the mode spacing in such a cavity would be as high as one-tenth of the recoil energy, allowing for a very efficient filter action, while the nonlinear coupling due to interatomic interactions could lead to bistability and limiting effects in the transmission of the atomic beam.     

A new selective synthesis of the Ile-allo-Thr-Gly tripeptide fragment of lysobactin

[formula: see text] trans-Aziridine-2-carboxylic acid derivatives are useful intermediates for the synthesis of threonine or allo-threonine through ring expansion and SN2 displacement, respectively. We describe here the preparation of the Ile-allo-Thr-Gly 11 fragment of Lysobactin via the aziridine 9 intermediate.     

Liquid‐Crystal‐Mediated Self‐Assembly of Porous α‐Fe2O3 Nanorods on PEDOT:PSS‐Functionalized Graphene as a Flexible Ternary Architecture for Capacitive Energy Storage

A novel aqueous‐based self‐assembly approach to a composite of iron oxide nanorods on conductive‐polymer (CP)‐functionalized, ultralarge graphene oxide (GO) liquid crystals (LCs) is demonstrated here for the fabrication of a flexible hybrid material for charge capacitive application. Uniform decoration of α‐Fe₂O₃ nanorods on a poly(3,4‐ethylene‐dioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)‐functionalized, ultralarge GO scaffold results in a 3D interconnected layer‐by‐layer (LBL) architecture. This advanced interpenetrating network of ternary components is lightweight, foldable, and possesses highly conductive pathways for facile ion transportation and charge storage, making it promising for high‐performance energy‐storage applications. Having such structural merits and good synergistic effects, the flexible architecture exhibits a high specific discharge capacitance of 875 F g^?1 and excellent volumetric specific capacitance of 868 F cm^?3 at 5 mV s^?1, as well as a promising energy density of 118 W h kg^?1 (at 0.5 A g^?1) and promising cyclability, with capacity retention of 100% after 5000 charge–discharge (CD) cycles. This synthesis method provides a simple, yet efficient approach for the solution‐processed LBL insertion of the hematite nanorods (HNR) into CP‐functionalized novel composite structure. It provides great promise for the fabrication of a variety of metal‐oxide (MO)‐nanomaterial‐based binder and current collector‐free flexible composite electrodes for high‐performance energy‐storage applications.     

Synthesis of dehydro-beta-amino esters via highly regioselective amination of allylic carbonates

The allylic amination of acetates and carbonates affords dehydro-beta-aminoesters, which are useful precursors of biologically active compounds. The uncatalyzed reaction proceeds via a S(N)2' mechanism. On the other hand, under palladium-catalyzed conditions, the reaction shows a strong solvent-dependent regiocontrol, affording exclusively one of the two possible regioisomers with complete transfer of chirality from the substrates to the products.     

Vacuum moulding of a superplastic in two dimensions

A mathematical model is proposed for the process of vacuum superplasticforming. The model exploits the fact that in most industrialapplications the sheet aspect ratio (thickness/sheet width)is small. After an initial consideration of some of the moregeneral properties and the literature of superplastic materials,the elastic/plastic deformation of an internally-inflated thin-walledcylinder is examined. Plates of arbitrary geometry are thenconsidered. A quasisteady model in which the sheet moves througha sequence of steady states is developed. Some simplified closed-formsolutions are examined, but for general cases a system of nonlinearpartial differential equations must be solved numerically. Anefficient and accurate semi-explicit numerical scheme is proposedand a simplified stability analysis is presented; the methodis then used to compute properties of superplastic vacuum mouldedsheets in a number of practically motivated cases.