The development of a new nitrating agent: the unusual regioselective nitration of diphenylpolyethylene glycols and phenylpolyethylene glycols with (trimethylsilyl) nitrate-BF3OEt2
Oxygen as moderator in the zinc-mediated reduction of aromatic nitro to azoxy compounds
作者:Faiz Ahmed Khan、Ch. Sudheer
DOI:10.1016/j.tetlet.2009.02.122
日期:2009.7
A simple and useful protocol for the reduction of nitro arenes to their corresponding azoxy derivatives by employing zinc and NH4Cl in a mixture of [bmim][BF4] and water is described. The selectivereduction of nitro to azoxy is attributed to the hitherto unknown moderating effect of oxygen on zinc metal.
The ringopening of epoxides with elementaliodine and bromine in the presence of three pyridine-containing macrocyclic diamides as new catalysts affords vicinal iodo alcohols and bromo alcohols in high yields. This new procedure occurs regioselectively under mild conditions in various aprotic solvents. The catalysts are easily recovered and can be reused several times.
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.
Novel ditopic receptors based on the P2N2 diphosphazane ring: synthesis and x-ray structural characterization of cis and trans bis(crown ether) annelated 1,3,2.lambda.5,4.lambda.5-diazadiphosphetidine 2,4-disulfide
作者:Jean Pierre Dutasta、Jean Paul Declercq、Carmen Esteban-Calderon、Bernard Tinant
DOI:10.1021/ja00200a036
日期:1989.8
Synthese d'un derive de bisether couronne diazadiphosphetidine-1,3,2,4 a partir de ditosylate de dioxa-3,6 octanediol
合成这些d'un衍生de双醚couronne diazadiphosphetidine-1,3,2,4 a partir de ditosylate de dioxa-3,6辛二醇