10-[1,1-Dichloro-4-(trimethylsilyl)but-1-en-3-yn-2-yl]-10 H -phenothiazine

The title compound, C 19 H 17 Cl 2 NSSi, is an enamine derivative, in which the N atom adopts a shallow trigonal–pyramidal geometry [displacement from the plane of its attached C atoms = 0.1383 (18) Å]. The dihedral angle between the plane through the three amino carbon atoms and the vinyl group is 89.47 (7)°. The phenothiazine unit has a butterfly structure and the central six-membered ring adopts a boat conformation. The fold angle between the benzene rings is 28.52 (7)°. The crystal structure features weak C sp 3 —H...Cl hydrogen bonds, H...S contacts and π–π stacking interactions between phenothiazine units.