Crystal structure of ethyl 2-amino-4-(4-meth­oxy­phen­yl)-4H-1-benzothieno[3,2-b]pyran-3-carboxyl­ate

Mohamed Bakhouch; Abdelali Kerbal; Mohamed El Yazidi; Mohamed Saadi; Lahcen El Ammari

doi:10.1107/S2056989015008154

. 2015 Apr 30;71(Pt 5):o366–o367. doi: 10.1107/S2056989015008154

Crystal structure of ethyl 2-amino-4-(4-methoxyphenyl)-4H-1-benzothieno[3,2-b]pyran-3-carboxylate

Mohamed Bakhouch ^a,^*, Abdelali Kerbal ^a, Mohamed El Yazidi ^a, Mohamed Saadi ^b, Lahcen El Ammari ^b

PMCID: PMC4420120 PMID: 25995952

Abstract

The molecule of the title compound, C₂₁H₁₉NO₄S, features a fused ring system whereby a five-membered ring is flanked by two six-membered rings. This is linked to an ethyl 3-carboxylate group and to a methoxybenzene group. The fused-ring system is quasi-planar, with the greatest deviation from the mean plane being 0.131 (1) Å for the methine C atom. The plane through the methoxybenzene ring is nearly perpendicular to that through the fused-ring system, as indicated by the dihedral angle of 85.72 (6)°. An intramolecular N—H⋯O hydrogen bond is noted. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, forming layers that stack along the a axis.

Keywords: crystal structure, thioaurones, hydrogen bonding

Related literature

For biological properties of substituted 2-amino-4-aryl-4H-pyran derivatives, see: Panda et al. (1997 ▸); Mungra et al. (2011 ▸). For the reactivity of (Z)-2-arylidenebenzo[b]thiophen-3(2H)-ones (thioaurones), see: Boughaleb et al. (2010 ▸; 2011 ▸); Bakhouch et al. (2014 ▸, 2015 ▸). For the preparation of the title compound, using condensation reactions, see: Daisley et al. (1982 ▸).

Experimental

Crystal data

C₂₁H₁₉NO₄S
M _r = 381.43
Monoclinic,
a = 11.8355 (7) Å
b = 18.6222 (11) Å
c = 9.0110 (5) Å
β = 106.502 (2)°
V = 1904.25 (19) Å³
Z = 4
Mo Kα radiation
μ = 0.20 mm⁻¹
T = 296 K
0.42 × 0.31 × 0.26 mm

Data collection

Bruker X8 APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1995 ▸) T _min = 0.673, T _max = 0.746
38870 measured reflections
5347 independent reflections
4118 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.130
S = 1.06
5347 reflections
244 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▸); cell refinement: SAINT (Bruker, 2009 ▸); data reduction: SAINT; 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: PLATON (Spek, 2009 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015008154/tk5366sup1.cif

e-71-0o366-sup1.cif^{(24.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015008154/tk5366Isup2.hkl

e-71-0o366-Isup2.hkl^{(261.9KB, hkl)}

Click here for additional data file.^{(6.3KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015008154/tk5366Isup3.cml

Click here for additional data file.^{(1.3MB, tif)}

. DOI: 10.1107/S2056989015008154/tk5366fig1.tif

Plot of the molecule of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small circles.

CCDC reference: 1061576

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

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N2H2BO2	0.86	2.08	2.6903(16)	128
N2H2AO2ⁱ	0.86	2.17	2.9964(16)	161
N2H2BO4ⁱⁱ	0.86	2.38	3.0908(17)	140

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

Acknowledgments

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray intensity measurements.

supplementary crystallographic information

S1. Comment

Substituted 2-amino-4-aryl-4H-pyran derivatives are an important class of heterocyclic compounds, which frequently exhibit a wide range of biological properties viz. antiproliferative, antitubercular activities (Panda et al., 1997; Mungra et al., 2011). Thus, in view of the large spectrum of applications of these compounds and in continuation of ongoing research focused on the reactivity of the (Z)-2-arylidenebenzo[b]thiophen- 3(2H)-ones (thioaurones) (Boughaleb et al., 2010; 2011; Bakhouch et al., 2014; 2015), the title compound was investigated This was prepared by the the action of ethyl cyanoacetate on (Z)-2-(4- methoxybenzylidene)benzo[b]thiophen-3(2H)-one (Daisley et al., 1982). The subsequent tautomeric transformation gives rise to ethyl 2-amino-4-(4-methoxyphenyl)-4H-1-benzothieno[3,2-b]pyran-3- carboxylate.

The molecule of the title compound is formed by three fused rings linked to an ethyl-3-carboxylate group and to a methoxybenzene group as shown in Fig. 1. The three fused rings (S1C1 to C11 O1) are nearly coplanar, with the maximum deviation from the mean plane being -0.131 (1) Å at C10, and makes a dihedral angle of 85.72 (6)° with the plans through this attached methoxyphenyl group.

In the crystal, the molecules are linked by N—H···O hydrogen bonds as shown in Fig. 2 and Table 1.

S2. Experimental

In a 100 ml flask equipped with a condenser was dissolved 4 mmol of (Z)-2-(4-methoxybenzylidene)-1-benzo[b]thiophen-3(2H)-one and 5 mmol of ethyl cyanoacetate in 30 ml of ethanol. Then, 1 ml of piperidine was added, and the reaction mixture was refluxed for 6 h. Thin layer chromatography revealed the formation of a single product. The organic phase was evaporated under reduced pressure. The resulting residue was recrystallized from ethanol by slow evaporation (Yield: 28%; m.pt: 395 K).