已经通过吡啶-2-硫代氧羰基(PTOC)竞争动力学方法在单个浓度点上确定了壬基从20种N-杂环卡宾和硼烷(NHC-硼烷)的络合物中提取氢的速率常数。速率常数的范围是从<1×10 4到8×10 4 M -1 s -1。它们几乎不依赖于卡宾核的电子性质,但是存在随着卡宾N取代基尺寸的减小而增加速率常数的趋势。已经鉴定出两种有希望的具有小的N取代基的新试剂(R = Me)。
Cyanoborohydrides are efficient reagents in the reductive addition reactions of alkyl iodides and electron-deficient olefins. In contrast to using tinreagents, the reaction took place chemoselectively at the carbon–iodine bond but not at the carbon–bromine or carbon–chlorine bond. The reaction system was successfully applied to three-component reactions, including radical carbonylation. The rate constant
氰基硼氢化物是烷基碘化物和缺电子烯烃的还原加成反应中的有效试剂。与使用锡试剂相反,该反应在碳碘键上发生化学选择,而在碳溴或碳氯键上没有发生。该反应体系已成功应用于三组分反应,包括自由基羰基化。通过动力学竞争法,在25°C下从氰基硼氢化四丁基铵中伯烷基脱氢的速率常数估计为<1×10 4 M –1 s –1。该值比氢化三丁基锡的值小3个数量级。
Synthesis and biological evaluation of dialkylsubstituted maleic anhydrides as novel inhibitors of Cdc25 dual specificity phosphatases
作者:Laurent Brault、Mickaël Denancé、Estelle Banaszak、Souhayla El Maadidi、Eric Battaglia、Denyse Bagrel、Mohammad Samadi
DOI:10.1016/j.ejmech.2006.09.014
日期:2007.2
An efficient synthesis of dialkyl substituted maleic anhydrides 1a-j is described. The inhibitory potential of these original anhydride derivatives was tested toward the three human isoforms A, B and C of dual specific phosphatases Cdc25. A micromolar range inhibition of Cdc25s was observed with the maleic anhydrides bearing simple alkyl side chains longer than C-9, to reach the optimal activity with a C-17 chain length. (c) 2006 Elsevier Masson SAS. All rights reserved.