Experimental and Theoretical Exploration of the Kinetics and Thermodynamics of the Nucleophile-Induced Fragmentation of Ylidenenorbornadiene Carboxylates
作者:Abigail D. Richardson、Scott J. L’Heureux、Ava M. Henry、Elizabeth A. McDonough、Cameron J. Fleischer、Cameron C. McMullen、Trevor R. Reynafarje、Gisele P. Guerrero、Quinn E. Williams、Qingyang Zhou、David M. Malouf、Spencer E. Thurman、Julia E. Soeller、Jerry Y. Sheng、Erica A. Medhurst、Angel E. Canales、Ty B. Cecil、K. N. Houk、Philip J. Costanzo、Daniel A. Bercovici
DOI:10.1021/acs.joc.3c00980
日期:2023.8.18
calculations were performed to investigate the mechanism of fragmentation and support an asynchronous retro-[4 + 2] cycloaddition transition state. The computations generally correlated well with the observed free energies of activation for four diastereomers of the model system as a whole, within 2.6 kcal/mol. However, the observed order of the fragmentation rates across the set of diastereomers deviated from
Thiol-Selective Fluorogenic Probes for Labeling and Release
作者:Vu Hong、Alexander A. Kislukhin、M. G. Finn
DOI:10.1021/ja809345d
日期:2009.7.29
powerful technique for the labeling of proteins. We report a new class of highlyreactive, selective, and fluorogenic probes for thiols in aqueous solution at neutral pH, based on the 7-oxanorbornadiene (OND) framework. The maleate moiety in 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid esters serves as both a tunable electrophile and an intramolecular quencher of an attached dansyl fluorophore.
硫醇烷基化是一种强大的蛋白质标记技术。我们报告了一类基于 7-氧降冰片二烯 (OND) 框架的新型高反应性、选择性和荧光探针,用于中性 pH 值水溶液中的硫醇。7-氧杂双环[2.2.1]hept-2,5-diene-2,3-二羧酸酯中的马来酸酯部分既可作为可调亲电试剂,也可作为连接丹磺酰荧光团的分子内猝灭剂。已发现硫醇以高速率(40-200 M(-1) s(-1) 的二阶速率常数)添加以提供显示荧光强度增强高达 180 倍的加合物。由此产生的加合物在通过两种机制进行裂解(释放)反应方面也是通用的。首先,在室温下,逆狄尔斯-阿尔德碎片的半衰期从几天到几周不等,并且还报道了不能进行环回复裂解的环氧化物衍生物。其次,单酰胺 OND 衍生物在加入硫醇后会快速闭合为琥珀酰亚胺,从而提供了一种硫醇触发的立即释放醇的机制。含有游离硫醇基团的肽和蛋白质用具有高化学选择性的 OND 亲电试剂标记。由于该系统
FICKENTSCHER K., ARCH. PHARM. <APBD-AJ>, 1975, 308, NO 4, 286-290