5H-​Imidazo[2,​1-​b]​[3]​benzazepine-​3-​carboxylic acid, 6,​11-​dihydro-​11-​[1-​[2-​[4-​(2-​quinolinylmethoxy)​phenyl]​ethyl]​-​4-​piperidinylidene]​-​, methyl ester