Efficient synthesis of 18–40 membered macrocyclic polyoxadiamides and polyoxatetraamides via ring closing metathesis
作者:Yehia A. Ibrahim、Elizabeth John
DOI:10.1016/j.tet.2005.10.031
日期:2006.1
Ringclosingmetathesis of the appropriate 1,ω-dienes led to efficient synthetic approaches towards the corresponding macrocyclic polyoxadiamides and tetraamides with 18–40 membered ring sizes in good to excellent yields using Grubbs' catalyst.
Synthesis and spectroscopic properties of new bis-tetrazoles
作者:Agnieszka Pazik、Anna Skwierawska
DOI:10.1007/s10847-012-0219-4
日期:2013.12
Syntheses of N,N′-phenyltetrazole podands link with aliphatic chains containing oxygen, nitrogen and sulphur atoms, are described. The complexing properties of these compounds towards metal cations (Fe2+, Cu2+, Zn2+, Co2+, Ni2+) were investigated by absorption and infrared spectroscopy. The UV–Vis titrations were performed to estimate the stability constant values of the respective complexes with Cu2+ ion. Changes in UV–Vis absorption spectra and IR spectra of compound 6 under various concentrations of Cu2+ ion in methanol suggest formation of very unstable complex. The structure of ligand 2 has been deduced by X-ray crystallography.
Stereochemistry of crown ethers. I. Conformational and dynamic behaviour ofN-tosyl-substituted diaza crown ethers
作者:E. Kleinpeter、M. Gäbler、W. Schroth
DOI:10.1002/mrc.1260260507
日期:1988.5
The variable-temperature 1H and 13C NMR spectra of some N-tosyl diaza crown ethers have been obtained. They are discussed with respect to the preferred conformers of the crowns and the free energies of activation of the interconversional process of the large ring. Both the preferred conformers and the ring interconversional barriers have been found to be strongly dependent on the structure and the ring size of the studied compounds.
Conformational Study of Isobutenylene Chains in Tandem Claisen Rearrangement Products. Insights from X-ray Crystallography and<sup>1</sup>H NMR for Salicylideneaniline Derivatives
A new variety of salicylideneaniline derivatives were prepared from a substituted aniline and a bis(hydroxybenzaldehyde) which has been synthesized through a tandem Claisenrearrangement reaction. X-ray crystal structures were obtained for many of the products. With respect to the conformation of their isobutenylene chain, the crystal structures can be classified into three groups: i.e., skew–skew
Chromogenic macrocyclic derivatives of azoles—synthesis and properties
作者:Ewa Wagner-Wysiecka、Elżbieta Luboch、Marzena Kowalczyk、Jan F Biernat
DOI:10.1016/s0040-4020(03)00618-5
日期:2003.6
The synthesis of macrocyclic chromogenic derivatives of pyrrole and imidazole is described. The complexing properties of these compounds with metal cations were investigated spectrophotometrically in acetonitrile. The synthesized crownethers were also tested as ion carriers in ion-selective membrane electrodes. The X-raystructure of one isomer of 18-membered pyrrole crownether is reported.