2,2,9-Trimethyl-2,3-dihydro­pyrano[2,3-a]carbazol-4-(11H)-one

The title compound, C18H17NO2, was prepared from 1-hydr­oxy-7-methyl­carbazole and 3,3-dimethyl­acrylic acid with trifluoro­acetic acid as the cyclization catalyst. The mol­ecules contain an essentially planar 6-methyl­indole unit. The second aromatic ring is significantly bent away from the plane of this unit, with maximum deviations of 0.171 (1) and 0.185 (1) Å for two of the C atoms. In the crystal structure, there are neither N—H⋯O hydrogen bonds nor π–π stacking between the aromatic sections of neighboring mol­ecules. There is only one weak C—H⋯O hydrogen bond and a number of weak C—H⋯π inter­actions

2,2,10-Trimethyl-2,3-dihydro­pyrano[2,3-a]carbazol-4(11H)-one

The title compound, C18H17NO2, was prepared from 1-hydr­oxy-8-methyl­carbazole and 3,3-dimethyl­acrylic acid with trifluoro­acetic acid as the cyclization catalyst. Due to the –CMe2– group, the mol­ecule is not quite planar. The packing is dominated by the strong N—H⋯O hydrogen bonds and some weaker C—H⋯O and C—H⋯π inter­actions. π–π Stacking inter­actions [centroid–centroid separation = 3.806 (2) Å] join neighboring mol­ecules into loosely connected inversion dimers

1-(1-Hydr­oxy-9H-carbazol-2-yl)-3-methyl­but-2-en-1-one

The title compound, C17H15NO2, was prepared as one of two products of the AlCl3/POCl3-catalysed reaction of 9-carbazol-1-ol with 3,3-dimethyacrylic acid. It crystallizes with two crystallographically independent mol­ecules, A and B, which are virtually superimposable but not related by any translational or other pseudosymmetry. Both independent mol­ecules 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 mol­ecules 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 mol­ecules allows the formation of alternating C—H⋯π inter­actions between A and B mol­ecules of parallel stacks

7,8,9,10-Tetra­hydro-2-methyl­cyclo­hepta­[b]indol-6(5H)-one

The title compound, C14H15NO, was synthesized from 2-hydroxy­methyl­enecyclo­hepta­none via a Japp–Klingemann acid-catalyzed cyclization. The seven-membered ring exhibits a slightly distorted envelope conformation. N—H⋯O hydrogen bonds form a centrosymmetric dimer; C—H⋯O hydrogen bonds and π–π stacking inter­actions (the centers of the atoms involved in the stacking interaction are separated by 3.504 Å) give rise to another type of centrosymmetric dimer. In combination, these inter­actions create a stair-like chain of mol­ecules that inter­acts only loosely with neighboring chains via van der Waals inter­actions and weak C—H⋯π contacts

2,2-Dimethyl-2,3-dihydropyrano[2,3-a]carbazol-4(11H)-one

The title compound, C17H15NO2, was prepared from 1-hydroxycarbazole and 3,3-dimethylacrylic acid with a mixture of AlCl3 and POCl3 as the cyclization catalyst. Owing to the presence of the –CMe2– group, the molecule is not quite planar. In the crystal structre, strong N—H...O hydrogen bonds and weaker C—H...π interactions occur, and a slipped π–π stacking interaction [centroid–centroid separation = 3.8425 (8) Å] is also observed