Crystal structure of (Z)-3-(4-meth­oxy­benzyl­idene)-2,3-di­hydro­benzo[b][1,4]thia­zepin-4(5H)-one

V Vinayagam; J Mohan Raj; S Murugavel; R Selvakumar; M Bakthadoss

doi:10.1107/S2056989014026267

. 2015 Jan 1;71(Pt 1):o21–o22. doi: 10.1107/S2056989014026267

Crystal structure of (Z)-3-(4-methoxybenzylidene)-2,3-dihydrobenzo[b][1,4]thiazepin-4(5H)-one

V Vinayagam ^a, J Mohan Raj ^b, S Murugavel ^c,^*, R Selvakumar ^a, M Bakthadoss ^a,^d,^*

PMCID: PMC4331881 PMID: 25705485

Abstract

In the title compound, C₁₇H₁₅NO₂S, the two C atoms linking the S and carbonyl C atoms of the seven-membered thiazepine ring are disordered over two sites, with occupancies of 0.511 (4) and 0.489 (4); both disorder components adopt distorted twist-boat conformations. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds link inverted-related molecules into dimers, incorporating R ₁ ²(6) and R ₂ ²(8) ring motifs; the acceptor carbonyl O atom is bifurcated. These dimers are further linked by C—H⋯O hydrogen bonds, forming supramolecular tapes running along the a axis.

Keywords: crystal structure; benzo[b][1,4]thiazepin-4(5H)-one; pharmaceutical properties; thiazepin derivatives; hydrogen bonding

Related literature

For the pharmaceutical properties of thiazepin derivatives, see: Lončar-Tomascovic et al. (2000 ▸); Rajsner et al. (1971 ▸); Metys & Metysová (1965 ▸). For related structures, see: Lakshmanan et al. (2012 ▸); Selvakumar et al. (2012 ▸). graphic file with name e-71-00o21-scheme1.jpg

Experimental

Crystal data

C₁₇H₁₅NO₂S
M _r = 297.36
Monoclinic,
a = 21.434 (5) Å
b = 5.715 (4) Å
c = 23.870 (5) Å
β = 101.091 (4)°
V = 2869 (2) Å³
Z = 8
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 293 K
0.30 × 0.30 × 0.25 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▸) T _min = 0.934, T _max = 0.944
17286 measured reflections
4099 independent reflections
2744 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.139
S = 1.03
4099 reflections
210 parameters
4 restraints
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.34 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▸); cell refinement: APEX2 and SAINT (Bruker, 2004 ▸); data reduction: SAINT and XPREP (Bruker, 2004 ▸); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989014026267/tk5350sup1.cif

e-71-00o21-sup1.cif^{(27.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989014026267/tk5350Isup2.hkl

e-71-00o21-Isup2.hkl^{(196.9KB, hkl)}

Click here for additional data file.^{(5.7KB, cml)}

Supporting information file. DOI: 10.1107/S2056989014026267/tk5350Isup3.cml

Click here for additional data file.^{(1.1MB, tif)}

. DOI: 10.1107/S2056989014026267/tk5350fig1.tif

Molecular structure of the title compound showing displacement ellipsoids at the 30% probability level. H atoms are presented as a small spheres of arbitrary radii.

Click here for additional data file.^{(2.1MB, tif)}

via a -x, −y, −z x, 1+y, z . DOI: 10.1107/S2056989014026267/tk5350fig2.tif

Supramolecular tape formation in the crystal packing of the title compound whereby bifurcated hydrogen bonds link inverted molecules into dimers sustained by N—H⋯O and C—H⋯O (red dashed lines) contacts are linked via C—H⋯O contacts (blue dashed lines) along a axis. [Symmetry code: (i) -x, −y, −z; (ii) x, 1+y, z].

CCDC reference: 1036763

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N1H1O1ⁱ	0.86	2.07	2.9291(18)	177
C6H6O1ⁱ	0.93	2.45	3.263(3)	146
C1BH1CO1ⁱⁱ	0.97	2.52	3.377(4)	147

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank Dr Babu Vargheese, SAIF, IIT, Madras, India, for his help with the data collection.

supplementary crystallographic information

S1. Structural commentary

The title compound is used as an intermediate for the synthesis of dosulepin, which is an antidepressant of the tricyclic family. Dosulepin prevents reabsorbing of serotonin and noradrenaline in the brain, helps to prolong the mood lightening effect of any released noradrenaline and serotonin, thus relieving depression. Dibenzo[c,e]thiazepin derivatives exhibit chiroptical properties (Tomascovic et al., 2000). Dibenzo[b,e]thiazepin-5,5-dioxide derivatives possess antihistaminic and antiallergenic activities (Rajsner et al., 1971). Benzene thiazepin derivatives are identified as a type of effective antihistaminic compounds (Metys et al., 1965). In view of this biological importance, the crystal structure of the title compound has been carried out and the results are presented here.

Fig. 1 shows a displacement ellipsoid plot of (I), with the atom numbering scheme. The geometric parameters of the title molecule agree well with those reported for similar structures (Selvakumar et al.., 2012; Lakshmanan et al., 2012). The sum of angles at N1 atom of the thiazepin ring (359.9°) is in accordance with sp² hybridization. Both the major and minor conformers of the disorderd thiazepine ring adopt distorted twist-boat conformations.

In the crystal, intermolecular bifurcated acceptor N1—H1···O1ⁱ and C6—H6···O1ⁱ (Table 1) hydrogen bonds link inverted-related molecules into dimers, incorporating R₁²(6) and R₂²(8) ring motifs. These dimers are further linked by C1B—H1C···O1ⁱⁱ (Table 1) hydrogen bonds forming supramolecular tapes running along the a axis (Fig. 2).

S2. Synthesis and crystallization

A mixture of (Z)-methyl 2-(bromomethyl)-3-(4-methoxyphenyl)acrylate (2 mmol) and o-aminothiophenol (2 mmol) in the presence of potassium tert-butoxide (4.8 mmol) in dry THF (10 ml) was stirred at room temperature for 1 h. After the completion of the reaction as indicated by TLC, the reaction mixture was concentrated and the resulting crude mass was diluted with water (20 ml) and extracted with ethyl acetate (3 x 20 ml). The organic layer was washed with brine (2 x 20 ml) and dried over anhydrous sodium sulfate. It was then concentrated to successfully provide the crude final product ((Z)-3-(4-methoxybenzylidene)-2,3-dihydrobenzo[b][1,4] thiazepin-4(5H)-one). This was purified by column chromatography on silica gel with ethylacetate/hexane 1:19 as eluent to afford the title compound in good yield (47 %). Single crystals suitable for X-ray diffraction were obtained by slow evaporation of its ethylacetate solution at room temperature.

S3. Refinement

Atoms C1 and C9 of the thiazepine ring are disordered over two positions (C1A/C1B and C9A/C9B) with refined occupancies of 0.511 (4) and 0.489 (4). The corresponding bond distances involving the disorderd atoms were restrained to be equal. H atoms were positioned geometrically, (C—H = 0.93–0.97 Å and N—H = 0.86 Å) constrained to ride on their parent atom, with U_iso(H)=1.5U_eq for methyl H atoms and 1.2U_eq(C) for other H atoms.