Substituent effects on the regioselectivity of maleamic acid formation and hydrogen chloride addition to N-aryl maleimides
作者:YELİZ FATURACI、NECDET COŞKUN
DOI:10.3906/kim-1203-34
日期:——
Itaconic anhydride reacts with aryl amines to give a substituent controlled equilibrium mixture of regioisomeric (Z)-2-methyl- and (Z)-3-methyl-4-oxo-4-(arylamino)but-2-enoic acids. Electron-donating groups favor nucleophilic attack on C-5 carbonyl, while the presence of electron-withdrawing groups enhances the bias for attack on C-2 carbonyl. The treatment of (Z)-2-methyl- and (Z)-3-methyl-4-oxo-4-(arylamino)but-2-enoic acids with SOCl_2-Et_3N in THF provided the corresponding maleimides in high yields while under the same conditions the maleic anhydride aryl amine addition products gave predominately the corresponding 3-chloro-1-arylpyrrolidine-2,5-diones and maleimides in substituent dependent ratio.
伊托酸酐与芳胺反应生成一种取代基控制的区域异构体平衡混合物,包括(Z)-2-甲基-和(Z)-3-甲基-4-氧代-4-(芳胺基)丁-2-烯酸。电子供给基团有利于对C-5羰基的亲核攻击,而电子吸引基团的存在则增强了对C-2羰基攻击的偏好。将(Z)-2-甲基-和(Z)-3-甲基-4-氧代-4-(芳胺基)丁-2-烯酸与SOCl₂-Et₃N在THF中处理,得到相应的马来咪唑,产率较高;而在相同条件下,马来酸酐与芳胺的加成产物主要生成相应的3-氯-1-芳基吡咯烷-2,5-二酮和马来咪唑,比例依赖于取代基。