Synthesis and Chemical Properties of (E)-3-[3-(2,5-Dioxo-2,5-dihydro-1H-pyrrol-1-yl)phenyl]propenoic Acid Derivatives

The reaction of m-aminocinnamic acid with maleic anhydride in acetone gave (2Z)-4-{3-[(E)-2-carboxyethenyl]anilino}-4-oxobut-2-enoic acid which underwent intramolecular cyclization in the presence of p-toluenesulfonic acid to produce (E)-3-[3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)phenyl]prop-2-enoic acid. m-Aminocinnamic acid potassium salts reacted with 2-(bromomethyl)-1,1-dichlorocyclopropane with retention of the three-membered ring, chemoselectively yielding 2,2-dichlorocyclopropylmethyl (2E)-3-(3-aminophenyl)­prop-2-enoate. Successive reactions of the latter with maleic anhydride and with acetic anhydride in the presence of sodium acetate afforded 2,2-dichlorocyclopropylmethyl (2E)-3-[3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)phenyl]prop-2-enoate which was subjected to aza-Michael reaction with secondary amines to obtain 2,2-dichlorocyclopropylmethyl (E)-3-[3-(3-dialkylamino-2,5-dioxopyrrolidin-1-yl)phenyl]prop-2-enoates.