(E)-3-Dimethyl­amino-1-(2,5-dimethyl­thio­phen-3-yl)prop-2-en-1-one

Mostafa M Ghorab; Mansour S Al-Said; Hazem A Ghabbour; Tze Shyang Chia; Hoong-Kun Fun

doi:10.1107/S1600536812021022

. 2012 May 12;68(Pt 6):o1712–o1713. doi: 10.1107/S1600536812021022

(E)-3-Dimethylamino-1-(2,5-dimethylthiophen-3-yl)prop-2-en-1-one

Mostafa M Ghorab ^a, Mansour S Al-Said ^a, Hazem A Ghabbour ^b, Tze Shyang Chia ^c, Hoong-Kun Fun ^c,^*,^‡

PMCID: PMC3379305 PMID: 22719503

Abstract

In the title compound, C₁₁H₁₅NOS, the 3-(dimethylamino)prop-2-en-1-one unit is approximately planar [maximum deviation = 0.0975 (14) Å] and its mean plane of seven non-H atoms makes a dihedral angle of 6.96 (10)° with the thiophene ring. In the crystal, molecules are linked by pairs of C—H⋯O hydrogen bonds into inversion dimers with R ₂ ²(14) ring motifs. The dimers are stacked along the c axis through C—H⋯π interactions. The two methyl groups, attached to the thiophene ring and the amino N atom, are each disordered over two orientations, with site-occupancy ratios of 0.59 (4):0.41 (4) and 0.74 (4):0.26 (4), respectively.

Related literature

For background to and the biological activity of thiophene derivatives, see: Ghorab et al. (2006 ▶); Al-Said et al. (2011 ▶); Shaaban et al. (2010 ▶); Krantz et al. (1990 ▶); Kikugawa & Ichino (1973 ▶); Gogte et al. (1967 ▶); Medower et al. (2008 ▶); Ghorab et al. (1998 ▶); Hassan et al. (1998 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). graphic file with name e-68-o1712-scheme1.jpg

Experimental

Crystal data

C₁₁H₁₅NOS
M _r = 209.30
Triclinic,
a = 5.9114 (2) Å
b = 7.5424 (2) Å
c = 13.9940 (4) Å
α = 81.274 (2)°
β = 88.828 (3)°
γ = 69.119 (3)°
V = 575.83 (3) Å³
Z = 2
Cu Kα radiation
μ = 2.24 mm⁻¹
T = 296 K
0.82 × 0.15 × 0.07 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.260, T _max = 0.859
7188 measured reflections
1897 independent reflections
1650 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.114
S = 1.08
1897 reflections
134 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812021022/is5136sup1.cif

e-68-o1712-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812021022/is5136Isup2.hkl

e-68-o1712-Isup2.hkl^{(93.3KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812021022/is5136Isup3.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 is the centroid of the S1/C1–C4 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10A⋯O1ⁱ	0.96	2.46	3.410 (3)	172
C5—H5B⋯Cg1ⁱⁱ	0.96	2.77	3.641 (3)	152

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

Acknowledgments

MMG, MSAS and HAG acknowledge the sponsorship of the Research Center, College of Pharmacy and the Deanship of Scientific Research, King Saud University, Riyadh, Saudi Arabia. HKF and TSC thank Universiti Sains Malaysia (USM) for the Research University Grant (1001/PFIZIK/811160). TSC also thanks the Malaysian Government and USM for the award of a research fellowship.

supplementary crystallographic information

Comment

As part of a program designed to investigate the biological activity of tricyclic and tetracyclic heterocyclic systems containing a thiophene ring as the central nucleus (Ghorab et al., 2006), recently we have put forward a convenient way to synthesize thiophene derivatives as anticancer agents (Al-Said et al., 2011; Shaaban et al., 2010). A survey of the literature showed that thiophene derivatives possess antihypertensive action (Krantz et al., 1990), platelet aggregation inhibition (Kikugawa & Ichino, 1973) and antineoplastic activities (Gogte et al., 1967; Medower et al., 2008). In addition, several nitrogen, oxygen and sulfur-containing heterocyclic compounds incorporating thiophene residues were found to possess interesting biological properties (Ghorab et al., 1998; Hassan et al., 1998). In continuation of our work on the synthesis of a novel thiophene derivative which might show significant anticancer activity, the title compound was prepared and its crystal structure is now reported.

The molecular structure of the title compound is shown in Fig. 1. The mean plane of dimethylthiophene ring [S1/C1–C6; maximum deviation = 0.0180 (12) Å at atom C6] forms a dihedral angle of 6.63 (12)° with the mean plane of the rest non-H atoms [O1/N1/C7–C11; maximum deviation = 0.0975 (14) Å at atom O1]. In the molecule, the hydrogen atoms attached to atoms C5 and C11 are each disordered over two positions with site-occupancy ratios of (H5A, H5B, H5C):(H5X, H5Y, H5Z) = 0.59 (4):0.41 (4) and (H11A, H11B, H11C):(H11X, H11Y, H11Z) = 0.74 (4):0.26 (4), respectively.

In the crystal (Fig. 2), molecules are linked by pairs of intermolecular C10—H10A···O1 hydrogen bonds into inversion dimers with an R₂²(14) ring motif (Bernstein et al., 1995) and are further stacked parallel to the a axis. The crystal packing is further stabilized by C—H···π interaction (Table 1), involving Cg1 which is the centroid of S1/C1–C4 ring.

Experimental

A mixture of 1-(2,5-dimethylthiophen-3-yl)ethanone (1.54 g, 0.01 mole) and dimethylformamide-dimethylacetal (1.19 g, 0.01 mole) in dry N,N-dimethylformamide (20 ml) was heated under reflux for 5 h. The reaction mixture was cooled and poured into ice water. The solid obtained was then recrystallized from ethanol to give the title compound. Single crystals suitable for X-ray structural analysis were obtained by slow evaporation from an N,N-dimethylformamide solution at room temperature.