Entacapone EP Impurity D

: 3-O-ethylentacapone; (2E)-2-cyano-3-(3-ethoxy-4-hydroxy-5-nitrophenyl)-N,N-diethylprop-2-enamide; N,N-diethyl-2-cyano-3-(3-ethoxy-4-hydroxy-5-nitrophenyl)acrylamide; (E)-2-Cyano-3-(3-ethoxy-4-hydroxy-5-nitrophenyl)-N,N-diethylacrylamide;