1-{3-[(7-Fluoro-9 H -pyrimido[4,5- b ]indol-4-yl)(meth-yl)amino]-piperidin-1-yl}propan-1-one.

The title compound, C 19 H 22 FN 5 O, has been synthesized as an inhibitor of glycogen synthase kinase-3β. Two mol-ecules inter-act via two N-H⋯N hydrogen bonds, forming centrosymmetric dimers.