5H-Thiochromeno[2,3-b]pyridine-5,10,10-trione

Abstract

The asymmetric unit of the title compound, C12H7NO3S, contains two independent molecules with different geometrical configurations. The dihedral angles between the benzene and pyridine rings in the two molecules are 3.7 (2) and 5.40 (19)°. The central heterocyclic fused rings have different puckering parameters [Q = 0.122 (3) Å, θ = 100.4 (13), ϕ = 185.3 (19)° in one molecule, 0.101 (3) Å, 101.4 (3) and 2 (2)° in the other]. The SO2 group is oriented at dihedral angles of 81.06 (14) and 82.58 (15)° with the benzene and pyridine rings, respectively, in one molecule [87.21 (14) and 87.66 (14)° in the second]. In the crystal, the molecules are linked into zigzag polymeric chains along the b axis by intermolecular C—H...O hydrogen bonding. π–π interactions with centroid–centroid distances in the range 3.825 (3)–4.153 (3) Å stabilize the structure. S—O...π and C—O...π interactions are also observed.