1-(1-Hydr-oxy-9H-carbazol-2-yl)-3-methyl-but-2-en-1-one

Abstract

The title compound, C(17)H(15)NO(2), was prepared as one of two products of the AlCl(3)/POCl(3)-catalysed reaction of 9-carbazol-1-ol with 3,3-dimethyacrylic acid. It crystallizes with two crystallographically independent mol-ecules, A and B, which are virtually superimposable but not related by any translational or other pseudosymmetry. Both independent mol-ecules are almost planar [r.m.s. deviations from planarity = 0.053 (1) and 0.079 (1) Å in A and B, respectively] and contain an intramolecular O-H⋯O hydrogen bond. Each type of mol-ecules is connected via pairs of N-H⋯O hydrogen bonds, forming centrosymmetric A(2) and B(2) dimers which are, in turn, arranged in offset π-stacks extending along the a-axis direction. The offset of the dimers and the tilt angle of the mol-ecules allows the formation of alternating C-H⋯π inter-actions between A and B mol-ecules of parallel stacks.

Fig. 1.

Synthesis of the title compound.

Fig. 2.

Thermal ellipsoid plot of the two independent molecules with atom numbering scheme. Atomic displacement parameters are at the 50% probablity level.

Fig. 3.

Least square overlay of molecules A (red) and B (blue)

Fig. 4.

One of the H-bonded dimers. Dashed blue lines respresent hydrogen bonds. Molecule B (not shown) forms dimers with essentially the same geometry. Symmetry operator ii: -x + 1, -y, -z + 1.

Fig. 5.

Packing diagram showing the arrangement of molecules and intermolecular interactions. Blue dashed lines: O—H···H and N—H···O hydrogen bonds. Orange dahsed lines: C—H···π interactions. Red dashed lines connect the centroids of π-stacked molecules (see text for details).