Benzamide, N-​[3-​(2-​fluorophenyl)​-​2-​methyl-​2-​propen-​1-​yl]​-​3,​4,​5-​trimethoxy-​N-​[2-​(1-​methyl-​2-​pyrrolidinyl)​ethyl]​-​, 2-​butenedioate (1:1)