3,4-Di­methyl­thieno[2,3-b]thio­phene-2,5-dicarbo­nitrile

Yahia Nasser Mabkhot; S S Al-Showiman; Assem Barakat; M Iqbal Choudhary; Sammer Yousuf

doi:10.1107/S1600536813017960

. 2013 Jul 17;69(Pt 8):o1272. doi: 10.1107/S1600536813017960

3,4-Dimethylthieno[2,3-b]thiophene-2,5-dicarbonitrile

Yahia Nasser Mabkhot ^a,^‡, S S Al-Showiman ^a, Assem Barakat ^a,^b, M Iqbal Choudhary ^c,^a, Sammer Yousuf ^c,^*

PMCID: PMC3793767 PMID: 24109354

Abstract

The asymmetric unit of the title compound, C₁₀H₆N₂S₂, contains two crystallographically independent but conformationally similar molecules. The fused thiophene ring cores are almost planar [maximum deviation = 0.027 (3) Å] with the thiophene rings forming dihedral angles of 0.5 (4)° in one molecule and 1.91 (4)° in the other. The crystal packing is stabilized only by van der Waals interactions.

Related literature

For the biological activity of thiophene derivatives, see: Mabkhot et al. (2013 ▶); Mishra et al. (2011 ▶). For the synthesis of fused heterocyclic compounds, see: Cornel & Kirsch (2001 ▶); Mashraqui et al. (1999 ▶). For crystal data for related thiophene compounds, see: Gunasekaran et al. (2009 ▶); Mashraqui et al. (2004 ▶). graphic file with name e-69-o1272-scheme1.jpg

Experimental

Crystal data

C₁₀H₆N₂S₂
M _r = 218.31
Triclinic,
a = 7.2573 (11) Å
b = 10.1538 (15) Å
c = 13.665 (2) Å
α = 94.467 (3)°
β = 99.120 (4)°
γ = 95.850 (4)°
V = 984.5 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.50 mm⁻¹
T = 273 K
0.37 × 0.15 × 0.11 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ▶) T _min = 0.838, T _max = 0.947
13821 measured reflections
4912 independent reflections
3074 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.055
wR(F ²) = 0.132
S = 0.99
4912 reflections
257 parameters
H-atom parameters constrained
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813017960/rz5077sup1.cif

e-69-o1272-sup1.cif^{(20.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813017960/rz5077Isup2.hkl

e-69-o1272-Isup2.hkl^{(240.6KB, hkl)}

Click here for additional data file.^{(3.7KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813017960/rz5077Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors extend their appreciation to the Deanship of Scientific Research at the King Saud University (Riyadh) for funding this study through the research grant No. RGP-VPP-007.

supplementary crystallographic information

Comment

Thiophene moieties containing heterocyclic compounds are known to have a number of biological activities, including anti-inflammatory, anti-oxidant and anti-glycation properties etc. (Mabkhot et al., 2013; Mishra et al. 2011). The title compound is a thiophene derivative, composed of two fused thiophene rings. It was synthesized as part of our ongoing research towards the synthesis of novel chemical entities with diverse biological activities.

The title, compound C₁₀H₆N₂S₂, contains two independent (S1–S2/C1–C6 and S3–S4/C11–C16) in the asymmetric unit (Fig. 1). Structurally it is similar to the previous reported compound diethyl 3,4-bis(acetoxymethyl)thieno-[2,3-b]thiophene-2,5-dicarboxylate (Gunasekaran et al., 2009) with the difference that four acetoxy methyl substituents has been replaced by two nitrile and two methyl substituents. The fused thiophene ring cores are almost planar [maximum deviation 0.027 (3) Å for atom C16] as indicated by the dihedral angles formed by the thiophene rings of 0.5 (4)° in one molecule and 1.91 (4)° in the other. The crystal packing (Fig. 2) is stabilized only by van der Waals interactions.

Experimental

The title compound was synthesized by following the procedure described in the literature (Mashraqui et al., 1999; Cornel et al., 2001). The compound was crystallized by using a mixture of dimethyl formamide (DMF) and dichloromethane (CH₂Cl₂) (1:1 v/v) at room temperature to obtain light brown crystals. M. p. 498 K. Anal. calcd. for C₁₀H₆N₂S₂: C, 55.04; H, 2.75; N, 12.84. Found: C, 54.82; H, 2.92; N, 12.97.

Spectral Data: IR (KBr, cm^-1): 2964, 2213 cm-1; ¹H-NMR (400 MHz, CDCl₃): δ 2.69 (s, 6H, CH₃); ¹³C-NMR (100 MHz, CDCl₃): δ 14.8 (2 CH₃), 108.5 (2 CAr), 113.3 (2 CN), 134.1 (CAr), 143.1 (2 CAr), 150.8 p.p.m. (CAr).