(2E)-2-(2,4-Dichloro­phenyl­sulfon­yl)-3-(3-methoxy­anilino)-3-(methyl­sulfan­yl)acrylonitrile

The title compound, C(17)H(14)Cl(2)N(2)O(3)S(2), and the 4-methyl­anilino analogue reported in the following paper have been used as starting materials to develop benzothia­zine derivatives with anti­malarial activity. The mol­ecule displays an E (trans) configuration about the central double bond. Due to conjugation in the C=C—C N group, the putative single bond shows a significant shortening [1.421 (3) Å]. The mol­ecule has a six-membered ring involving an intra­molecular N—H⋯O(sulfon­yl) bond, which is an example of resonance-assisted hydrogen bonding. There is also an intra­molecular N—H⋯Cl hydrogen bond. In the crystal structure, bonds of the C—H⋯O(sulfon­yl) type form chains that run along [101], while N—H⋯O(sulfon­yl) bonds connect centrosymmetrically related molecules in pairs of these chains, forming ribbons. Comparison of the N⋯O distances in the intra- and inter­molecular N—H⋯O(sulfon­yl) bonds reveals that the π-bond co-operativity results in a strengthening of the intra­molecular hydrogen bond. There are also π–π inter­actions between benzene rings of pairs of centrosymmetrically related mol­ecules [centroid–centroid distance = 3.8612 (13) Å], as well as C—H⋯π interactions.