Gravar-mail: (1S,3aS,4S,7aS)-Ethyl 1-benzyl-2-(4-meth­oxy­benz­yl)-6,7-dimethyl-3-oxo-2,3,3a,4,5,7a-hexa­hydro-1H-isoindole-4-carboxyl­ate dichloro­methane monosolvate