2-Pyrrolidinone, 4-(aminomethyl)-1-(phenylmethyl)-, (E)-2-butenedioate (2:1) 4-(Aminomethyl)-1-(phenylmethyl)-2-pyrrolidinone (E)-2-butenedioate (2:1) 4-Aminomethyl-1-benzylpyrrolidin-2-one fumarate (2:1) 97205-34-0 97205-35-1 Nebracetam fumarate WEB 1881 WEB 1881FU