通过使用激光闪光光解技术,已经直接测量了在 20 o C 下在 18 个三芳基甲基和 10 个二芳基甲基阳离子与叠氮化物的不同组成的乙腈-水 (AN-W) 溶液中反应的速率常数 k AZ 和 k S和溶剂。阳离子具有取决于取代基的k S 并且从~10 1 到~10 7 s -1 变化。对于更稳定的离子,k AZ 也发生变化,随着给电子量的减少而增加,并且随着乙腈含量的增加而增加多达10 3 。然而,对于不太稳定的阳离子,速率常数与取代基无关
Protolytic defluorination of trifluoromethyl-substituted arenes
作者:Anila Kethe、Adam F. Tracy、Douglas A. Klumpp
DOI:10.1039/c0ob01276a
日期:——
Bronsted superacids. The products from these reactions suggest the formation of reactive electrophiles, such as carbocations, acylium cations or equivalent electrophilic species. As such, Friedel-Crafts-type reactions occur between these species and arene nucleophiles. NMRstudies were done, and the results suggest the formation of an acyl group from the trifluoromethyl groups in the superacid.
Triphenylbutanamines: Kinesin Spindle Protein Inhibitors with in Vivo Antitumor Activity
作者:Fang Wang、James A. D. Good、Oliver Rath、Hung Yi Kristal Kaan、Oliver B. Sutcliffe、Simon P. Mackay、Frank Kozielski
DOI:10.1021/jm201195m
日期:2012.2.23
The human mitotic kinesin Eg5 represents a novel mitotic spindle target for cancer chemotherapy. We previously identified S-trityl-L-cysteine (STLC) and related analogues as selective potent inhibitors of Eg5. We herein report on the development of a series of 4,4,4-triphenylbutan-1-amine inhibitors derived from the STLC scaffold. This new generation systematically improves on potency: the most potent C-trityl analogues exhibit K-i(aPP) <= 10 nM and GI(50) approximate to 50 nM, comparable to results from the phase II clinical benchmark ispinesib. Crystallographic studies reveal that they adopt the same overall binding configuration as S-trityl analogues at an allosteric site formed by loop L5 of Eg5. Evaluation of their druglike properties reveals favorable profiles for future development and, in the clinical candidate ispinesib, moderate hERG and CYP inhibition. One triphenylbutanamine analogue and ispinesib possess very good bioavailability (51% and 45%, respectively), with the former showing in vivo antitumor growth activity in nude mice xenograft studies.
Acidities and homolytic bond dissociation energies (BDEs) of benzyl-type carbon-hydrogen bonds in sterically congested substrates
作者:F. G. Bordwell、Jin Pei Cheng、A. V. Satish、Cary L. Twyman
DOI:10.1021/jo00050a032
日期:1992.11
Equilibrium acidities in DMSO and BDEs for the benzylic C-H bonds are reported for 19 triphenylmethanes, three 9,10-dihydroanthracenes, and nine xanthenes. The phenyl groups in triphenylmethane, 9-phenyl-9,10-dihydroanthracene, and 9-phenylxanthene are shown to be constrained in their ability to delocalize either the negative charges in the anions formed by loss of a proton or the odd electrons released by loss of hydrogen atom. Analysis of the pK(HA) values showed, however, that strong solvation of para electron-withdrawing substituents in a phenyl ring of each of these substrates caused the corresponding anion to adopt a conformation where effective conjugative overlap occurred between the substituent and the carbanion via the phenyl ring. In other words, a conformational change was induced via a substituent solvation assisted resonance (SSAR) effect. In sharp contrast to these large solvation-induced substituent effects on anion stabilities, remote substituent effects on radical stabilities in these congested species were found to be negligible. Substitution of either a p-toluenesulfonyl or CN group into the 9-position of xanthene caused a large increase in acidity, but the p-CH3C6H4SO2 group caused an increase in the BDE of the acidic C-H bond, whereas the CN group caused a small decrease.
YAMATAKA, HIROSHI;KAWAFUJI, YUKIE;NAGAREDA, KATSUSHI;MIYANO, NOBUTAKA;HAN+, J. ORG. CHEM., 54,(1989) N9, C. 4706-4708