Spiro[9H-​imidazo[1,​2-​a]​indole-​9,​3'-​[1,​5]​(iminomethano)​[3H]​[1,​4]​oxazepino[3,​4-​b]​quinazoline]​-​3,​7',​13'(1'H,​2H)​-​trione, 1,​4',​5',​9a-​tetrahydro-​1',​2-​dimethyl-​, (1'R,​2S,​3'S,​5'S,​9aS)​-