The action of amines on citraconic anhydride. X-Ray crystal structure of (Z)-2-methyl-3-pyrrolidinocarbonylpropenoic acid
作者:Ahmet E. Baydar、Gerhard V. Boyd、John Aupers、Peter F. Lindley
DOI:10.1039/p19810002890
日期:——
The reaction of citraconic anydride with 15 primary and secondary amines gave mixtures of isomeric citraconamic acids (2) and (3), in which the former predominated. The more abundant isomers rearranged to the thermodynamically stable N-substituted (Z)-2-methyl-3-carbamoylpropenic acids (3) on warming. The structure of the pyrrolidide (3q) was confirmed by X-ray analysis. An unsuccessful attempt to
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.