Bruceolline D: 3,3-dimethyl-1H,4H-cyclo­penta­[b]indol-2(3H)-one

The title compound, C₁₃H₁₃NO, crystallizes with four independent mol­ecules in the asymmetric unit. The 12-membered penta­[b]indole rings are essentially planar, with maximum deviations ranging from 0.034 (4) to 0.036 (4) Å in the four unique mol­ecules. In the crystal, weak C—H...O inter­actions are observed, which link the mol­ecules into chains along [010].