Crystal structure of diethyl 2-amino-6-[(thio-phen-3-yl)ethyn-yl]azulene-1,3-di-carboxyl-ate.

The title compound, C22H19NO4S, has an almost planar geometry supported by intra-molecular N-H⋯O and C-H⋯O hydrogen bonds. The thio-phene ring is inclined to the azulene ring by 4.85 (16)°, while the eth-oxy-carbonyl groups are inclined to the azulene ring by 7.0 (2) and 5.7 (2)°. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(12) ring motif. The dimers are linked via C-H⋯π inter-actions, forming sheets parallel to (10-1).