in the presence of primary amines or secondary α,ω-diamines has been applied to macroheterocyclic ringsynthesis. Starting from (hetero)diallylic systems, 12- to 36-membered polyheterocycles have been readily obtained in up to 56% yield. In addition, we show that the macrocyclic systems thus obtained can be debenzylated and that the resulting macrocyclic diamines undergo a second ring-closing bis(hy
Synthesis and alkali metal picrate extraction capabilities of novel, cage-functionalized, pyridine containing crown ethers and cryptands
作者:Alan P. Marchand、Hyun-Soon Chong、Sulejman Alihodz˛ić、William H. Watson、Satish G. Bodige
DOI:10.1016/s0040-4020(99)00521-9
日期:1999.8
The syntheses of novel cage-functionalized crown ethers,11–13, that contain one or more pyridyl units are reported. The results of alkali metal picrate extraction experiments performed by using11 and12 are compared with those obtained by using the corresponding model (non-cage) crownethers. Cage-functionalized crown ether11 displays greater avidity toward Li+ picratevis-a`-vis the corresponding model
One-step Synthesis of 2,11,20-<i>N</i>,<i>N</i>′,<i>N</i>″-Tribenzyl-2,11,20-triaza[3.3.3](2,6)pyridinophane. Reinvestigation of the Reaction of Benzylamine with 2,6-Bis(bromomethyl)pyridine
作者:Geunsu Lee、Yuji Miyahara、Takahiko Inazu
DOI:10.1246/cl.1996.873
日期:1996.10
The reaction of benzylamine with 2,6-bis(bromomethyl)pyridine has now been found to provide the trimeric title compound as the major product instead of the reported dimer. When the reaction was conducted in two steps, a new tetrameric pyridinophane was isolated as the major product.
Large pKa Shifts of ?-Carbon Acids Induced by Copper(II) Complexes
作者:Zhenlin Zhong、Brenda J. Postnikova、Robert E. Hanes、Vincent M. Lynch、Eric V. Anslyn
DOI:10.1002/chem.200400396
日期:2005.4.8
A series of synthetic receptors (4-6) incorporating metal ions, specifically copper(II), were examined for their ability to enhance the acidity of active methylene compounds. The copper(II) complexes were observed to reduce the pKa of 1,3-diketone carbon acids in acetonitrile by as much as 12 pKa units. The relatively large pKa reduction achieved by the complex is attributed to the electrostatic interaction
作者:Scrimin, Paolo、Tecilla, Paolo、Tonellato, Umberto、Valle, Giovanni、Veronese, Andrea
DOI:10.1016/0040-4020(94)00913-f
日期:——
3·2Cu, defined by X-ray analysis. From a kinetic study of the catalytic activity of 3·2Cu in the hydrolysis of the p-nitrophenyl ester of β-alanine (AlaPNP), a β-amino acid, clear evidence of co-operativity of the two metalions was obtained. Such an allosteric effect was not observed in the hydrolysis of the p-nitrophenyl ester of leucine (LeuPNP), an α-amino acid. The reactivity of 3·2Cu was compared