title: Methyl 3-[(1,1-dioxo-1λ(6),2-benzothiazol-3-yl)amino]-5-nitrothiophene-2-carboxyl-ate.
abstract: The title nitro-thio-phene compound, C(13)H(9)N(3)O(6)S(2), crystallizes with two independent mol-ecules in the asymmetric unit; the mol-ecular structure of each is stabilized by an intra-molecular N-H⋯O hydrogen bond. The two mol-ecules adopt flattened but slightly different conformations, viz. the dihedral angle between the thio-phene ring and the essentailly planar 1,2-benzisothia-zole fragment (r.m.s. deviations = 0.0227 and 0.0108 Å, respectively) is 15.62 (11)° in one mol-ecule and 5.46 (11)° in the other. In the crystal, mol-ecules are arranged into layers parallel to (-111) with weak C(ar)-H⋯O inter-actions formed within the layer. N-H⋯O hydrogen bonds also occur. There are π-π stacking inter-actions between the mol-ecules in neighbouring layers, the distance between the centroids of the 1,2-benzisothia-zole benzene rings being 3.8660 (16) Å. Moreover, dipolar S=O⋯C=O inter-actions with an O⋯C distance of 2.893 (3) Å are observed between the symmetry-independent mol-ecules in different layers. The title compound showed weak inhibition of HLE (human leukocyte elastase).
authors.affiliation: Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Ernst-Moritz-Arndt-University, Friedrich-Ludwig-Jahn-Str. 17, Greifswald, D-17489,  Germany ; Council Scientific and Industrial Research (CSIR) Head Quarter, Anusandhan Bhavan, 2 Rafi Marg, Delhi-110001,  India.
authors.forename: Haridas B
authors.initials: HB
authors.lastname: Rode
authors.forename: Jarosław
authors.initials: J
authors.lastname: Chojnacki
authors.forename: Hans-Hartwig
authors.initials: HH
authors.lastname: Otto