离子液体(IL)玻璃作为具有独特物理化学性质的不寻常介质,最近引起了人们的广泛关注。特别是,脉冲电子顺磁共振 (EPR) 光谱证明了咪唑鎓 IL 玻璃中分子迁移率随温度升高的异常抑制。尽管这种行为已被证明源自IL阳离子烷基链的动力学,但周围质子引起的电子自旋弛豫的作用仍不清楚。在这项工作中,我们合成了两种基于氘化咪唑的离子液体,以减少自由基探针和离子液体烷基链之间的电子-核耦合,并研究了这些玻璃中的分子迁移率。发现氘化和质子化类似物所获得的趋势非常相似,因此排除了弛豫引起的伪影,并可靠地证明了异质 IL 玻璃中观察到的异常的结构基础。
functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional
abundant and sustainable alcohols as the alkylating reagents, a new and direct alkylation method has been demonstrated. This method enables the selective alkylation of the less substituted pyridyl ring at the β-site of aryl-1,8-naphthyridines, affording the desired products in moderate to excellent yields upon isolation. The method proceeds under transition-metal-free conditions in an atom- and step-economic
[<i>N</i><sup>ε</sup>-(γ-glutamyl) lysine] as a potential biomarker in neurological diseases : New detection method and fragmentation pathways
作者:Guylaine Hoffner、Yannik Hoppilliard、Guillaume van der Rest、Patrick Dansette、Philippe Djian、Gilles Ohanessian
DOI:10.1002/jms.1331
日期:2008.4
shown to be adequate markers for quantitation experiments. In order to gain a better understanding of the fragmentation processes, detailed quantumchemical calculations have been performed at levels which are expected to provide good accuracy. A thorough study has been carried out with a reduced model in which only the 'active' part of the molecule is retained. This allowed obtaining full mechanistic
蛋白质聚集体是许多中枢神经系统疾病(例如polyQ扩张疾病)的特征。通过转谷氨酰胺酶的作用形成的共价键被认为参与了这些聚集体的稳定化。转谷氨酰胺酶催化在谷氨酰胺基和多肽的赖氨酰残基的侧链之间形成交联。在神经元聚集体的最终蛋白水解消化物中,对异肽N(ε)-(γ-谷氨酰基)赖氨酸(iEK)的鉴定将证明转谷氨酰胺酶参与了神经系统疾病。为了鉴定和量化神经系统疾病患者的大脑中存在的iEK,开发了一种结合液相色谱和多步质谱的方法。由于聚集蛋白的消化物中可能存在iEK的等压肽,因此片段诊断离子的选择至关重要。这些离子是通过在iEK上进行质谱鉴定而确定的,该iEK在羧基官能团和末端胺上进行了衍生化以提高灵敏度。氘代分子以及(13)C(6)-和(15)N(2)-同位素异构体用于在多步裂解中衍生纤丝。已经鉴定出主要的碎片模式,因此显示出两个离子(m / z 396 [MH-56-42 u](+)和350 [MH-56-88
Mechanistic Investigation of the Ruthenium-N-Heterocyclic-Carbene-Catalyzed Amidation of Amines with Alcohols
作者:Ilya S. Makarov、Peter Fristrup、Robert Madsen
DOI:10.1002/chem.201202400
日期:2012.12.3
The mechanism of the ruthenium–N‐heterocyclic‐carbene‐catalyzed formation of amides from alcohols and amines was investigated by experimental techniques (Hammett studies, kinetic isotope effects) and by a computational study with dispersion‐corrected density functional theory (DFT/M06). The Hammett study indicated that a small positive charge builds‐up at the benzylic position in the transition state
First synthesis of 3-S-glutathionylhexanal-d and its bisulfite adduct
作者:Jennifer R. Muhl、Lisa I. Pilkington、Rebecca C. Deed
DOI:10.1016/j.tetlet.2020.152100
日期:2020.7
Application of this synthesis to 1-butanol-d10, conserved eight deuteriums, producing glut-3SH-al-d8, which can be used as an internal standard for future work on the occurrence and evolution of glut-3SH-al in wine systems. Additionally, both glut-3SH-SO3 and glut-3SH-SO3-d8 were synthesised from the corresponding aldehyde, enabling further study of the role of these bisulfite adducts in 3SH biogenesis
3-Sulfanylhexan-1-ol(3SH)是一种白葡萄酒的香气,具有热带水果的香气。从1-丁醇开始,开发了可靠的合成途径,即3-S-谷胱甘肽己醛(glut-3SH-al)(尚未深入研究的3SH前体)。将该合成物应用于1-丁醇-d 10,保存了八个氘,产生了glut-3SH-al- d 8,可用作将来研究葡萄酒中glut-3SH-al的发生和发展的内在标准。系统。此外,这两种GLUT-3SH-SO 3和GLUT-3SH-SO 3 - d 8,从相应的醛合成,使在生物发生3SH这些亚硫酸氢盐加合物的作用的进一步研究。