The displacement reactions of ethyl 1-cyclopropyl-5, 6, 7, 8-tetrafluoro-4(1H)-oxoquinoline-3-carboxylate (7) and its carboxylic acid 8 with amine nucleophiles were examined. The nucleophilic displacement occurred regioselectively at the C-5 or C-7 position depending on the substrate (7 or 8) and solvent selected; this finding permitted the introduction of an optional nucleophile preferentially into the required position at either C-5 or C-7, or into both positions with a desired combination of nucleophiles. Taking advantage of this regioselectivity, we prepared various 5-substituted 6, 7, 8-trifluoro- and 7-substituted 5, 6, 8-trifluoro-1-cyclopropyl-4(1H)-oxoquinoline-3-carboxylic acids. Furthermore, the use of the boron-chelated derivative of the carboxylic acid 8 was favorable for the regioselective synthesis of 7-substituted 5, 6, 8-trifluoroquinolones.
研究了1-环丙基-5,6,7,8-四
氟-4(1H)-氧代
喹啉-3-
甲酸乙酯(7)及其
羧酸8与胺亲核试剂的置换反应。根据所选择的底物(7 或 8)和溶剂,亲核置换区域选择性地发生在 C-5 或 C-7 位置;这一发现允许将任选的亲核试剂优先引入到所需的C-5或C-7位置,或者引入具有所需亲核试剂组合的两个位置。利用这种区域选择性,我们制备了各种5-取代的6,7,8-三
氟-和7-取代的5,6,8-三
氟-1-环丙基-4(1H)-氧代
喹啉-3-羧酸。此外,使用
羧酸8的
硼螯合衍
生物有利于7-取代的5,6,8-三
氟喹诺酮的区域选择性合成。