Crystal structure of 8-eth­oxy-3-(4-nitro­phen­yl)-2H-chromen-2-one

Shashikanth Walki; S Naveen; S Kenchanna; K M Mahadevan; M N Kumara; N K Lokanath

doi:10.1107/S2056989015019325

. 2015 Oct 17;71(Pt 11):o860–o861. doi: 10.1107/S2056989015019325

Crystal structure of 8-ethoxy-3-(4-nitrophenyl)-2H-chromen-2-one

Shashikanth Walki ^a, S Naveen ^b, S Kenchanna ^a, K M Mahadevan ^a, M N Kumara ^c, N K Lokanath ^d,^*

PMCID: PMC4645040 PMID: 26594565

Abstract

In the title compound, C₁₇H₁₃NO₅, the coumarin ring system is essentially planar (r.m.s. deviation = 0.008 Å). The nitrophenyl ring makes a dihedral angle of 25.27 (9)° with the coumarin ring plane. The nitro group is almost coplanar with the phenyl ring to which it is attached, making a dihedral angle of 4.3 (3)°. The ethoxy group is inclined to the coumarin ring plane by 4.1 (2)°. Electron delocalization was found at the short bridging C—C bond with a bond length of 1.354 (2) Å. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming sheets in the bc plane. The sheets are linked via π–π stacking [centroid–centroid distances = 3.5688 (13) and 3.7514 (13) Å], forming a three-dimensional structure.

Keywords: crystal structure, coumarin, chromen, C—H⋯O hydrogen bonds, π–π stacking

Related literature

For coumarin derivatives as fluorescent brighteners, see: Tian et al. (2000 ▸). For details of natural or synthetic coumarins which inhibit lipid peroxidation and scavenge hydroxyl radicals and superoxide anions, see: Naveen et al. (2007 ▸). For further details of our research on coumarins, see: Naveen et al. (2006a ▸,b ▸). graphic file with name e-71-0o860-scheme1.jpg

Experimental

Crystal data

C₁₇H₁₃NO₅
M _r = 311.28
Orthorhombic,
a = 6.8118 (9) Å
b = 13.6726 (18) Å
c = 15.909 (2) Å
V = 1481.7 (3) Å³
Z = 4
Cu Kα radiation
μ = 0.87 mm⁻¹
T = 296 K
0.29 × 0.26 × 0.21 mm

Data collection

Bruker X8 Proteum diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2013 ▸) T _min = 0.786, T _max = 0.838
6729 measured reflections
2371 independent reflections
2225 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.131
S = 1.03
2371 reflections
210 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.21 e Å⁻³
Absolute structure: 957 Friedel pairs; Flack (1983 ▸)
Absolute structure parameter: 0.1 (2)

Data collection: APEX2 (Bruker, 2013 ▸); cell refinement: SAINT (Bruker, 2013 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: Mercury (Macrae et al., 2008 ▸); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015019325/su5224sup1.cif

e-71-0o860-sup1.cif^{(25.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015019325/su5224Isup2.hkl

e-71-0o860-Isup2.hkl^{(116.5KB, hkl)}

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

Supporting information file. DOI: 10.1107/S2056989015019325/su5224Isup3.cml

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

. DOI: 10.1107/S2056989015019325/su5224fig1.tif

A view of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Click here for additional data file.^{(1.2MB, tif)}

b . DOI: 10.1107/S2056989015019325/su5224fig2.tif

A viewed along the b axis of the crystal packing of the title compound.

CCDC reference: 1430858

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

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
C4H4O22ⁱ	0.93	2.53	3.453(2)	171
C8H8O14ⁱⁱ	0.93	2.31	3.226(2)	166
C20H20O22ⁱ	0.93	2.52	3.275(3)	138

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

Acknowledgments

The authors are thankful to IOE, Vijnana Bhavana, University of Mysore, for providing the single-crystal X-ray diffraction facility. The authors acknowledge the financial support received from DST, New Delhi, under SERB reference No: SB/EMEQ-351/2013 (dated 29-10-2013).

supplementary crystallographic information

S1. Comment

Coumarin derivatives are found to be one of the major groups of compounds used as fluorescent brighteners (Tian et al., 2000) or fluorescent dyes and they have exhibited good bleed fastness and durability for coating plastics or in acrylic lacquers. Several natural or synthetic coumarins with various hydroxyl and other substituents were found to inhibit lipid peroxidation and to scavenge hydroxyl radicals and superoxide anions (Naveen et al., 2007). As a part of our ongoing research on coumarins (Naveen et al., 2006a,b), we report herein on the synthesis, characterization and crystal structure of the title compound. The compound is being assessed for biological activity.

The molecular structure of the title compound is shown in Fig. 1. The coumarin ring is essentially planar with the two axially fused rings forming a dihedral angle of 0.45 (10) °, while the 4-nitrophenyl ring makes a dihedral angle of 25.27 (9) Å with the coumarin mean plane. The nitro group is almost planar to the phenyl ring to which it is attached with a dihedral angle of 4.3 (3) °. The ethoxy group is inclined to the coumarin ring plane by 4.1 (2) °.

Electron delocalization was found at the short C3—C4 bond with a bond length of 1.354 (2) Å. Here as well as in other coumarin compounds reported earlier an important asymmetry in the O—C—O bond angle was detected [O1—C2—O14 = 116.10 (14)° and O14—C2—C3 = 126.14 (15)°]. The bond angles, O1—C10—C9 and C4—C5—C6, at the junction of the two rings in the coumarin moiety are 117.97 (15)° and 123.44 (16)° respectively.

In the crystal, molecules are linked via C–H···O hydrogen bonds forming sheets in the bc plane. The sheets are linked via π-π interactions [Cg1···Cg3ⁱ = 3.5688 (13) Å; Cg1···Cg3ⁱⁱ = 3.75114 (13) Å; Cg1 and Cg3 are the centroids of rings O1/C2—C5/C10 and C15—C20; symmetry codes: (i) x-1/2, -y+3/2, -z+1; (ii) x+1/2, -y+3/2, -z+1] forming a three-dimensional structure (Table 1 and Fig. 2)

S2. Synthesis and crystallization

A mixture of 0.512 g m (3.083 mmol) of 3-ethoxysalicylaldehyde and 0.50 g m (3.083 mmol) of 4-nitro phenylacetonitrile were dissolved in ethanol (25 ml), followed by the addition of 0.525 g m (6.16 mmol) of piperidine and then the reaction mixture was stirred at room temperature for 3 h. The completion of the reaction was monitored by thin layer chromatography [petroleum ether and ethyl acetate (8:2 v/v)]. After completion the reaction mixture was filtered and washed with diethylether giving a yellow precipitation. This product was refluxed with 10% acetic acid for 2 s and then the crude product was filtered and washed with water. It was further purified by recrystallization using acetone as solvent to give yellow crystals of the title compound in good yield (m.p.: 475-477 K; yield: 91%). ¹H NMR(400 MHz, DMSO-d₆): δ = 8.47 (s, 1H, Ar—H), 8.34 (dd, J= 2.08 Hz, 6.94 Hz, 2H, Ar—H), 8.05 (dd, J=2.0 Hz, 6.96 Hz, 2H, Ar—H), 7.34–7.36(m, 3H, Ar—H), 4.22(q, J= 6.92 Hz, 2H, CH2), 1.43(t, J=6.96 Hz,3H, CH₃). ¹³C NMR (400 MHz, DMSO-d₆): δ = 45.554, 142.927, 145.554, 142.927, 129.804, 124.807, 123.375, 120.205, 119.868, 115.603, 64.470, 14.63. IR (KBr) (v_max/cm^-1): 2925 (C—H), 1700 (C=O), 1346 (N—O), 1097 (C—O—C). Mass spectra gave a molecular ion peak at m/z = 311.4[M⁺].

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The hydrogen atom were fixed geometrically (C—H= 0.93–0.96 Å) and allowed to ride on their parent atoms with U_iso(H) =1.5U_eq(C-methyl) and = 1.2U_eq(C) for other H atoms.