Regiochemical Flexibility: The Optional Functionalization of 2,3,5-Trihalopyridines at the 4- or 6-Position
作者:Carla Bobbio、Manfred Schlosser
DOI:10.1002/1099-0690(200112)2001:23<4533::aid-ejoc4533>3.0.co;2-1
日期:2001.12
ice to afford the carboxylic acids. Upon neutralization, the 6-iodopyridines were obtained. These compds. readily exchanged the heavy halogen for metal when treated with isopropylmagnesium chloride. In this way, functional groups could be selectively introduced in the 6-position. Employing carbon dioxide routinely as the model electrophile, trihalopyridinecarboxylic acids were formed which, all unknown
使用 2,3,5-三氯吡啶、3,5-二氯-2-氟吡啶和 5-氯-2,3-二氟吡啶作为底物进行去质子化研究。与二异丙基氨基锂 (LDA) 反应后,去质子化仅发生在 4 位。随后的羧化和碘化产生酸和 4-碘吡啶。后者的曝光。对锂 2,2,6,6-四甲基哌啶 (LITMP) 造成去质子化并立即导致碘迁移。中间体用干冰捕获以提供羧酸。中和后得到6-碘吡啶。这些化合物。当用异丙基氯化镁处理时,很容易将重卤素换成金属。通过这种方式,可以在 6 位选择性地引入官能团。常规使用二氧化碳作为模型亲电试剂,形成了三卤代吡啶羧酸,目前尚不清楚,这将为药物研究提供有价值的新构建块。此外,2-位卤素的选择性亲核置换可以产生各种各样的新结构。[在 SciFinder (R) 上]