Kinetics of the Self-Assembly of α-Cyclodextrin [2]Pseudorotaxanes with 1,12-Bis(4-(α-alkyl-α-methylmethanol)pyridinium)dodecane Dications in Aqueous Solution
摘要:
The kinetics and thermodynamics of the self-assembly of a series of [2]pseudorotaxanes comprised of alpha-cyclodextrin (alpha-CD) and racemic 1,12-bis(4-(alpha-alkyl-alpha-methylmethanol)pyridinium)dodecane dications (L(CH2)(12)L2+) in aqueous;solutions have been investigated using H-1 NMR spectroscopy. The mechanism of assembly involves inclusion of the alpha-methyl-alpha-alkylmethanol substituent groups (-C(CH3)(OH)R, where R = Me, Et, Pr, Bu, allyl, and 4-butenyl) by alpha-CD, followed by a rate-determining passage of the cyclodextrin over the pyridinium group onto the dodecamethylene chain. Dicationic threads containing end groups with R = Ph or i-Pr or where L = 4-(alpha,alpha-diethylmethanol)pyridinium did not form alpha-cyclodextrin pseudorotaxanes, even after prolonged heating. The trends in the rate and activation parameters may be related to the size, shape, and hydrophobicity of the alkyl substituents and are compared with several other systems from the literature. An increase in the length and hydrophobicity of the alkyl group increases the strength of end group inclusion and decreases the rate of threading. In addition, the presence of unsaturation in the alkyl substituent (allyl vs propyl and 4-butenyl vs butyl) results in an increase in the threading rate constant.
Kinetics of the Self-Assembly of α-Cyclodextrin [2]Pseudorotaxanes with 1,12-Bis(4-(α-alkyl-α-methylmethanol)pyridinium)dodecane Dications in Aqueous Solution
摘要:
The kinetics and thermodynamics of the self-assembly of a series of [2]pseudorotaxanes comprised of alpha-cyclodextrin (alpha-CD) and racemic 1,12-bis(4-(alpha-alkyl-alpha-methylmethanol)pyridinium)dodecane dications (L(CH2)(12)L2+) in aqueous;solutions have been investigated using H-1 NMR spectroscopy. The mechanism of assembly involves inclusion of the alpha-methyl-alpha-alkylmethanol substituent groups (-C(CH3)(OH)R, where R = Me, Et, Pr, Bu, allyl, and 4-butenyl) by alpha-CD, followed by a rate-determining passage of the cyclodextrin over the pyridinium group onto the dodecamethylene chain. Dicationic threads containing end groups with R = Ph or i-Pr or where L = 4-(alpha,alpha-diethylmethanol)pyridinium did not form alpha-cyclodextrin pseudorotaxanes, even after prolonged heating. The trends in the rate and activation parameters may be related to the size, shape, and hydrophobicity of the alkyl substituents and are compared with several other systems from the literature. An increase in the length and hydrophobicity of the alkyl group increases the strength of end group inclusion and decreases the rate of threading. In addition, the presence of unsaturation in the alkyl substituent (allyl vs propyl and 4-butenyl vs butyl) results in an increase in the threading rate constant.
Highly Efficient Alkylation to Ketones and Aldimines with Grignard Reagents Catalyzed by Zinc(II) Chloride
作者:Manabu Hatano、Shinji Suzuki、Kazuaki Ishihara
DOI:10.1021/ja0628405
日期:2006.8.1
efficient alkylation to ketones and aldimines with Grignardreagents in the presence of catalytic trialkylzinc(II) ate complexes derived from ZnCl2 (10 mol %) in situ was developed. This simple Zn(II)-catalyzed alkylation could minimize the well-known but serious problems with the use of only Grignardreagents, which leads to reduction and aldol side products, and the yield of desired alkylation products
在由 ZnCl2 (10 mol%) 衍生的催化三烷基锌 (II) 酸酯配合物的存在下,使用格氏试剂高效地烷基化为酮和醛亚胺。这种简单的 Zn(II) 催化烷基化可以最大限度地减少仅使用格氏试剂而导致还原和羟醛副产物的众所周知但严重的问题,并且可以提高所需烷基化产物的产率。
TETRACYCLIC INHIBITORS OF JANUS KINASES
申请人:Rodgers James D.
公开号:US20090215766A1
公开(公告)日:2009-08-27
The present invention provides compounds that modulate the activity of Janus kinases and are useful in the treatment of diseases related to activity of Janus kinases including, for example, immune-related diseases and cancer.