Crystal structure of 1,5-diethyl-1H-1,5-benzodiazepine-2,4(3H,5H)-dithione

In the title compound, C13H16N2S2, the seven-membered ring adopts a boat conformation, with the two phenylene C atoms representing the stern and the methylene C atom as the prow. The thione S atoms and N-bound ethyl groups lie on the opposite side of the molecule to the phenylene ring so that the molecule approximates mirror symmetry. In the crystal, supramolecular layers in the bc plane are sustained by a pair of C—H⋯S interactions to the same S atom acceptor.

In the title compound, C 13 H 16 N 2 S 2 , the seven-membered ring adopts a boat conformation, with the two phenylene C atoms representing the stern and the methylene C atom as the prow. The thione S atoms and N-bound ethyl groups lie on the opposite side of the molecule to the phenylene ring so that the molecule approximates mirror symmetry. In the crystal, supramolecular layers in the bc plane are sustained by a pair of C-HÁ Á ÁS interactions to the same S atom acceptor. Keywords: crystal structure; benzodiazepine; boat conformation.. CCDC reference: 1040593
Supporting information for this paper is available from the IUCr electronic archives (Reference: TK5353).

S1. Introduction
Benzodiazepines and their derivatives are an important class of bioactive compound. They have attracted attention of chemists in the field of pharmaceuticals (Kumar et al., 2006). Some benzodiazepine derivatives have been widely used as anti-bacterial, anti-fungal, analgesic and anti-convulsant agents (Swamy et al. 2008).

S3. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. H-atoms were placed in calculated positions (C-H 0.95-0.99 Å) and were included in the refinement in the riding model approximation, with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for all other H atoms.

S4. Results and discussion
The title compound crystallizes in the space group C2/c with one independent molecule in the asymmetric unit ( Fig. 1).
In the molecule, the diazepine ring system adopts a boat conformation with the two C1 and C6 atoms representing the stern and the C8 atom the prow with maximum deviation of 0.6626 (12)Å. The puckering parameters are: q2=0.9557 (11) Å, q3 = 0.2328 (11) Å, φ2 = 29.60 (7)° and φ3 = 128.4 (3)°. The mean plane of the diazepine ring is twisted with respect to that of the benzene ring by 32.27 (5) The structure of the title compound, showing atom labelling and 30% probability displacement ellipsoids. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.