Synthesis of Substituted Phenothiazines Analogous to Methylene Blue by Electrophilic and Nucleophilic Aromatic Substitutions in Tandem. A Mechanistic Perspective.
作者:Nicholas Leventis、Muguo Chen、Chariklia Sotiriou-Leventis
DOI:10.1016/s0040-4020(97)00349-9
日期:1997.7
acetic acid to give 3,7-dibromophenothiazin-5-ium bromide (8), according to a reaction sequence that involves two electrophilic aromatic substitutions and one oxidation. Subsequently, 8 reacting with diallylamine or allylmethylamine via two nucleophilic aromatic substitution steps gave 3,7-bis[di(2-propenyl)amino]phenothiazin-5-ium bromide (3) or 3,7-bis[methyl, (2-propenyl)amino]phenothiazin-5-ium bromide
由吩噻嗪(6)首先与过量的溴在乙酸中反应,合成3,7-二取代的吩噻嗪(1),然后根据反应生成3,7-二溴吩噻嗪-5-溴化铵(8)。该序列涉及两个亲电芳族取代和一个氧化。随后,8通过两个亲核芳族取代步骤与二烯丙基胺或烯丙基甲胺反应,得到3,7-双[二(2-丙烯基)氨基]吩噻嗪-5-溴化铵(3)或3,7-双[甲基](2-丙烯基]氨基]吩噻嗪-5-溴化铵(4),类似于亚甲蓝的化合物。第二步溶剂的选择至关重要,因为3,7-二溴吩噻嗪-5-溴化物非常活泼,并且容易在3和7位发生不可逆的氧化,还原和ipso攻击。当将CHCl 3或CH 2 Cl 2用作亲核芳族取代步骤的溶剂时,亚甲基蓝类似物3和4的最佳收率(〜63%)。这些溶剂可溶解亚甲蓝类似物,但不能溶解3,7-二溴吩噻嗪-5-溴化铵。©1997爱思唯尔科学有限公司。