Crystal structure of ethyl (6-hy­droxy-1-benzo­furan-3-yl)acetate sesquihydrate

Krishnaswamy, G.; Suchetan, P.A.; Sreenivasa, S.; Naveen, S.; Lokanath, N.K.; Aruna Kumar, D.B.

doi:10.1107/S1600536814024349

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Volume 70| Part 12| December 2014| Pages 541-543

doi:10.1107/S1600536814024349

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Crystal structure of ethyl (6-hydroxy-1-benzofuran-3-yl)acetate sesquihydrate

G. Krishnaswamy,^a P. A. Suchetan,^a S. Sreenivasa,^a S. Naveen,^b N. K. Lokanath ^c and D. B. Aruna Kumar ^a ^*

^aDepartment of Studies and Research in Chemistry, Tumkur University, Tumkur 572 103, India, ^bInstitution of Excellence, Vijnana Bhavan, University of Mysore, Manasagangotri, Mysore 570 006, India, and ^cDepartment of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, India
^*Correspondence e-mail: nirmaldb@rediffmail.com

Edited by M. Gdaniec, Adam Mickiewicz University, Poland (Received 16 October 2014; accepted 5 November 2014; online 21 November 2014)

In the title hydrate, C₁₂H₁₂O₄·1.5H₂O, one of the water molecules in the asymmetric unit is located on a twofold rotation axis. The molecule of the benzofuran derivative is essentially planar (r.m.s. deviation for the non-H atoms = 0.021 Å), with the ester group adopting a fully extended conformation. In the crystal, O—H⋯O hydrogen bonds between the water molecules and the hydroxy groups generate a centrosymmetric R₆⁶(12) ring motif. These R₆⁶(12) rings are fused, forming a one-dimensional motif extending along the c-axis direction.

Keywords: crystal structure; hydrates; O—H⋯O hydrogen bonds; C—H⋯π interactions; benzofuran.

CCDC reference: 1032887

1. Chemical context

Furan heterocycles are of interest for synthetic chemists as they possess various pharmacological and biological activities including antituberculosis (Tawari et al., 2010 ), anti-inflammatory (Shin et al., 2011 ) and antibacterial (Kirilmis et al., 2008 ) activity. Substituted benzofurans have found applications as fluorescent sensors (Oter et al., 2007 ), anti-oxidants, brightening agents and drugs. Moreover, benzofuran carboxylic acid ethyl ester also exhibits selective cytotoxicity against a tumorigenic cell line (Hayakawa et al., 2004 ). In view of the above facts, and as a continuation of our structural studies on benzofurans (Arunakumar, Krishnaswamy et al., 2014 ; Arunakumar, Desai Nivedita et al., 2014 ), the title compound has been synthesized, characterized by FT IR, ¹H NMR and LC–MS methods and its crystal structure determined.

2. Structural commentary

The title compound crystallizes as a 1.5-hydrate with one of the symmetry-independent water molecules occupying a special position of C₂ symmetry. The molecular structure of the title compound is shown in Fig. 1. The molecule is almost planar (r.m.s. deviation for the non-H atoms = 0.021 Å) and the ethyl acetate fragment adopts a fully extended conformation.

Figure 1
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.

3. Supramolecular features

Hydrogen bonds (Table 1) between two hydroxy groups and four water molecules generate a centrosymmetric $[R_{6}^{6}]$ (12) ring motif. The rings are fused at the position of the O5 atoms, i.e. through water molecules located at special positions. In effect, two antiparallel chains of hydrogen bonds are formed that are fused at every fourth O atom and which propagate along the crystallographic c-axis (Fig. 2). In the crystal, the components are connected into a three-dimensional network through additional hydrogen bonds between the water molecule in a general position and the ester carbonyl group. In addition to strong hydrogen bonds, weaker C—H⋯π interactions are observed between the methylene group H atoms and the benzene and furan rings (Fig. 3 and Table 1).

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the C7/C13/C9/C8/C11/C14 benzene ring and Cg2 is the centroid of the O16/C6/C10/C7/C13 furan ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O2	0.82	1.88	2.692 (4)	170
O2—H2A⋯O3ⁱ	0.85	1.96	2.788 (4)	164
O2—H2B⋯O5ⁱⁱ	0.85	2.00	2.844 (4)	174
O5—H5⋯O1ⁱⁱⁱ	0.85 (4)	2.09 (4)	2.870 (3)	152 (4)
C17—H17B⋯Cg1^iv	0.97	2.68	3.485 (3)	140
C17—H17A⋯Cg2^v	0.97	2.99	3.889 (3)	154
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) $[x, -y+2, z+{\script{1\over 2}}]$ ; (iii) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (iv) $[-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z]$ ; (v) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z]$ .

Figure 2
Hydrogen-bonding interactions (dashed lines) featuring a fused $[R_{6}^{6}]$ (12) ring motif.

Figure 3
The C—H⋯π interactions (dashed lines) in the title compound.

4. Synthesis and crystallization

2-(6-Hydroxy-1-benzofuran-3-yl)acetic acid (2.0 g, 0.010 mmol) was taken in a round-bottomed flask containing ethanol (10 mL). Concentrated sulfuric acid (1 mL) was added and the reaction mixture was refluxed for 4 h at 353 K. After completion of the reaction, the reaction mixture was poured into ice-cold water and extracted to an ethyl acetate layer. The organic layer was washed with water followed by brine solution and dried over anhydrous sodium sulfate. The organic layer was concentrated under vacuum, giving a reddish residue. The residue was purified by column chromatography using silica gel (60–120 mesh) and ethyl acetate/petroleum ether (2:8) as eluent, affording a colourless crystalline product. Crystals suitable for X-ray analysis were formed by slow evaporation of the solution of the compound in ethyl acetate and petroleum ether (3:2) at room temperature. As the product had been water worked-up, water might have entered in the solid interstices during work-up.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The H atoms of water molecules were located from a difference Fourier map. The H atom bound to O5 was freely refined and those bound to O2 had the O—H distances restrained to 0.85 (2) Å. The remaining C/O-bound H atoms were fixed geometrically (C—H = 0.93–0.97 and O—H = 0.82 Å) and allowed to ride on their parent atoms with U_iso(H) = 1.5U_eq(C,O) for methyl and hydroxy H atoms, and 1.2U_eq(C) for other H atoms.

Table 2
Experimental details

Crystal data
Chemical formula	2C₁₂H₁₂O₄·3H₂O
M_r	494.48
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	29.191 (6), 7.3291 (17), 12.587 (3)
β (°)	113.074 (13)
V (Å³)	2477.4 (9)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	0.89
Crystal size (mm)	0.47 × 0.34 × 0.26

Data collection
Diffractometer	Bruker APEXII
Absorption correction	Multi-scan (SADABS; Bruker, 2009 )
T_min, T_max	0.730, 0.793
No. of measured, independent and observed [I > 2σ(I)] reflections	8441, 1968, 1132
R_int	0.114
(sin θ/λ)_max (Å⁻¹)	0.584

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.067, 0.224, 1.06
No. of reflections	1968
No. of parameters	168
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.40, −0.54
Computer programs: APEX2, SAINT-Plus and XPREP (Bruker, 2009), SHELXS97 and SHELXL97 (Sheldrick, 2008 ) and Mercury (Macrae et al., 2008 ).

Supporting information

CCDC reference: 1032887

Crystal structure: contains datablock I. DOI: 10.1107/S1600536814024349/gk2620sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814024349/gk2620Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814024349/gk2620Isup3.cml

checkCIF report

Chemical context top

Furan heterocycles are interesting for synthetic chemists as they possess various pharmacological and biological activities including antituberculosis (Tawari et al., 2010), anti-inflammatory (Shin et al., 2011) and antibacterial (Kirilmis et al., 2008). Substituted benzofurans have found applications as fluorescent sensors (Oter et al., 2007), anti-oxidants, brightening agents and drugs. Moreover, benzofuran carboxylic acid ethyl ester exhibits selective cytotoxicity against a tumorigenic cell line (Hayakawa et al., 2004). In view of the above facts, and as a continuation of our structural studies on benzofurans (Arunakumar, Krishnaswamy et al., 2014; Arunakumar, Desai Nivedita et al., 2014), the title compound has been synthesized, characterized by FT IR, ¹H NMR and LC–MS methods and its crystal structure determined.

Structural commentary top

Supramolecular features top

Hydrogen bonds (Table 1) between two hydroxy groups and four water molecules generate a centrosymmetric R₆⁶(12) ring motif. The rings are fused at the position of the O5 atoms, i.e. through water molecules located at special positions. In effect, two antiparallel chains of hydrogen bonds are formed that are fused at every fourth O atom and which propagate along the crystallographic c-axis (Fig. 2). The crystal components are connected into a three-dimensional network through additional hydrogen bonds between the water molecule in a general position and the ester carbonyl group. In addition to strong hydrogen bonds, weaker C—H···π interactions are observed between the methylene group H atoms and the benzene and furan rings (Fig. 3 and Table 1).

Synthesis and crystallization top

2-(6-Hydroxy-1-benzofuran-3-yl)acetic acid (2.0 g, 0.010 mmol) was taken in a round-bottomed flask containing ethanol (10 ml). Concentrated sulfuric acid (1 ml) was added and the reaction mixture was refluxed for 4 h at 353 K. After completion of the reaction, the reaction mixture was poured into ice-cold water and extracted to an ethyl acetate layer. The organic layer was washed with water followed by brine solution and dried over anhydrous sodium sulfate. The organic layer was concentrated under vacuum, giving a reddish residue. The residue was purified by column chromatography using silica gel (60–120 mesh) and ethyl acetate/petroleum ether (2:8) as eluent, affording a colourless crystalline product. Crystals suitable for X-ray analysis were formed by slow evaporation of the solution of the compound in ethyl acetate and petroleum ether (3:2) at room temperature.

Refinement top

Related literature top

For related literature, see: Hayakawa et al. (2004); Kirilmis et al. (2008); Oter et al. (2007); Shin et al. (2011); Tawari et al. (2010).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: APEX2 and SAINT-Plus (Bruker, 2009); data reduction: SAINT-Plus and XPREP (Bruker, 2009); 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 (Sheldrick, 2008).

Figures top

The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.

Hydrogen-bonding interactions (dashed lines) featuring a fused R₆⁶(12) ring motif.

The C—H···π interactions (dashed lines) in the title compound.

Ethyl (6-hydroxy-1-benzofuran-3-yl)acetate sesquihydrate top

Crystal data top

2C₁₂H₁₂O₄·3H₂O	prism
M_r = 494.48	D_x = 1.326 Mg m⁻³
Monoclinic, C2/c	Melting point: 447 K
Hall symbol: -C 2yc	Cu Kα radiation, λ = 1.54178 Å
a = 29.191 (6) Å	Cell parameters from 125 reflections
b = 7.3291 (17) Å	θ = 6.3–64.2°
c = 12.587 (3) Å	µ = 0.89 mm⁻¹
β = 113.074 (13)°	T = 296 K
V = 2477.4 (9) Å³	Prism, colourless
Z = 4	0.47 × 0.34 × 0.26 mm
F(000) = 1048

Data collection top

Bruker APEXII diffractometer	1968 independent reflections
Radiation source: fine-focus sealed tube	1132 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.114
phi and ϕ scans	θ_max = 64.2°, θ_min = 6.3°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −31→33
T_min = 0.730, T_max = 0.793	k = −8→8
8441 measured reflections	l = −13→13

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.067	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.224	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ²(F_o²) + (0.1328P)²] where P = (F_o² + 2F_c²)/3
1968 reflections	(Δ/σ)_max < 0.001
168 parameters	Δρ_max = 0.40 e Å⁻³
1 restraint	Δρ_min = −0.54 e Å⁻³

Crystal data top

2C₁₂H₁₂O₄·3H₂O	V = 2477.4 (9) Å³
M_r = 494.48	Z = 4
Monoclinic, C2/c	Cu Kα radiation
a = 29.191 (6) Å	µ = 0.89 mm⁻¹
b = 7.3291 (17) Å	T = 296 K
c = 12.587 (3) Å	0.47 × 0.34 × 0.26 mm
β = 113.074 (13)°

Data collection top

Bruker APEXII diffractometer	1968 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	1132 reflections with I > 2σ(I)
T_min = 0.730, T_max = 0.793	R_int = 0.114
8441 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.067	1 restraint
wR(F²) = 0.224	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	Δρ_max = 0.40 e Å⁻³
1968 reflections	Δρ_min = −0.54 e Å⁻³
168 parameters

Special details top

Experimental. Thin-layer chromatography (TLC) was carried out on Merck pre-coated silica gel plates to monitor the progress of the reaction. The FT–IR spectra were recorded as KBr pellets using JASCO FT–IR-4100 spectrophotometer in the range 4000–400 cm^-1 at a resolution of 2 cm^-1. ¹H NMR spectra were recorded in CDCl₃ and DMSO-d₆ on a JEOL-400 MHz NMR instrument. Chemical shifts are reported in δ values in parts per million relative to TMS. Mass spectral data were obtained on an Agilent LC–MS column C-18 instrument.

The IR spectrum of (I) exhibits strong bands at 1686 cm^-1 and 1193 cm^-1 due to C=O and C-O stretchings, respectively. A single band appearing at 3340 cm^-1 is due to OH group stretching. Appearance of bands in the range 3011–2907 cm^-1 is due to aromatic stretching and bands in the range 2970–2815 cm^-1 are due to C—H stretching, thus confirming the presence of the saturated hydrocarbons in (I).

The ¹H NMR spectrum of (I) shows peaks at δ 9.53 (s, 1H, Ar-OH), 6.69 (s, 1H, furan-H), 7.35–7.33 (d, 1H, Ar-H), 6.88–6.87 (d, 1H, Ar-H), 6.75–6.72 (q, 1H, Ar-H), 4.12–4.07 (q, 2H, OCH₂), 3.34 (s, 2H, CH₂), 1.12–1.17 (t, 3H, CH₃). The LC–MS spectrum shows the appearance of molecular ion peaks at m/z 221 and 222 values, confirming the structure of the compound.

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O16	0.74036 (8)	0.9708 (4)	0.7193 (2)	0.0605 (10)
C7	0.71590 (10)	0.9610 (4)	0.5264 (3)	0.0378 (10)
C8	0.61898 (11)	0.8688 (4)	0.4921 (3)	0.0391 (11)
C9	0.65308 (11)	0.8957 (4)	0.6055 (3)	0.0448 (11)
H9	0.6444	0.8846	0.6689	0.054*
C10	0.76857 (11)	1.0071 (4)	0.5752 (3)	0.0389 (10)
C11	0.63322 (12)	0.8851 (4)	0.3998 (3)	0.0458 (11)
H11	0.6097	0.8646	0.3255	0.055*
C12	0.92468 (12)	1.1583 (5)	0.5340 (3)	0.0523 (12)
H12A	0.9449	1.0616	0.5824	0.063*
H12B	0.9307	1.2693	0.5793	0.063*
C13	0.70057 (11)	0.9401 (4)	0.6160 (3)	0.0405 (11)
C14	0.68085 (12)	0.9305 (4)	0.4142 (3)	0.0427 (11)
H14	0.6897	0.9409	0.3510	0.051*
C15	0.93746 (14)	1.1861 (6)	0.4312 (4)	0.0680 (15)
H15A	0.9289	1.0786	0.3839	0.102*
H15B	0.9725	1.2092	0.4564	0.102*
H15C	0.9191	1.2884	0.3873	0.102*
C17	0.79811 (11)	1.0380 (4)	0.5048 (3)	0.0420 (11)
H17A	0.7819	1.1334	0.4495	0.050*
H17B	0.7967	0.9275	0.4612	0.050*
C18	0.85173 (12)	1.0893 (4)	0.5659 (3)	0.0410 (11)
O1	0.57017 (8)	0.8246 (4)	0.4691 (2)	0.0512 (9)
H1	0.5667	0.8083	0.5301	0.077*
O2	0.54997 (10)	0.7984 (4)	0.6597 (2)	0.0639 (10)
H2A	0.5687	0.7310	0.7144	0.096*
H2B	0.5365	0.8790	0.6866	0.096*
O3	0.87331 (9)	1.1106 (3)	0.6691 (2)	0.0586 (9)
O4	0.87249 (9)	1.1095 (3)	0.4913 (2)	0.0523 (9)
O5	0.5000	0.9512 (5)	0.2500	0.0598 (13)
C6	0.77984 (12)	1.0112 (5)	0.6912 (3)	0.0526 (12)
H6	0.8114	1.0388	0.7458	0.063*
H5	0.4849 (19)	0.879 (5)	0.194 (3)	0.104 (18)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O16	0.0473 (13)	0.0952 (19)	0.0313 (16)	−0.0166 (11)	0.0069 (14)	−0.0131 (13)
C7	0.0405 (15)	0.0324 (14)	0.036 (2)	0.0010 (10)	0.0098 (17)	0.0003 (14)
C8	0.0393 (15)	0.0418 (16)	0.035 (2)	0.0035 (10)	0.0137 (17)	0.0009 (15)
C9	0.0420 (16)	0.0557 (18)	0.034 (2)	0.0000 (12)	0.0121 (17)	−0.0065 (16)
C10	0.0428 (15)	0.0362 (15)	0.036 (2)	−0.0021 (10)	0.0130 (17)	−0.0033 (15)
C11	0.0424 (16)	0.0578 (19)	0.028 (2)	0.0010 (12)	0.0038 (18)	0.0009 (16)
C12	0.0406 (17)	0.060 (2)	0.054 (3)	−0.0104 (12)	0.0155 (19)	0.0029 (19)
C13	0.0419 (16)	0.0455 (16)	0.029 (2)	−0.0013 (12)	0.0082 (17)	−0.0069 (15)
C14	0.0474 (16)	0.0490 (17)	0.029 (2)	0.0053 (12)	0.0125 (17)	0.0032 (15)
C15	0.059 (2)	0.088 (3)	0.064 (3)	−0.0184 (18)	0.032 (2)	−0.005 (2)
C17	0.0401 (15)	0.0410 (16)	0.038 (2)	−0.0023 (11)	0.0077 (16)	−0.0006 (15)
C18	0.0442 (16)	0.0346 (15)	0.042 (2)	−0.0033 (11)	0.0148 (19)	0.0008 (15)
O1	0.0382 (11)	0.0702 (15)	0.0411 (15)	−0.0032 (9)	0.0112 (12)	0.0030 (14)
O2	0.0591 (15)	0.0818 (19)	0.0477 (17)	0.0184 (11)	0.0176 (14)	0.0097 (15)
O3	0.0555 (14)	0.0800 (17)	0.0344 (16)	−0.0188 (11)	0.0114 (14)	−0.0080 (13)
O4	0.0423 (12)	0.0624 (14)	0.0454 (16)	−0.0119 (9)	0.0100 (13)	0.0003 (12)
O5	0.0500 (18)	0.065 (2)	0.053 (3)	0.000	0.008 (2)	0.000
C6	0.0398 (17)	0.079 (2)	0.040 (2)	−0.0127 (14)	0.0166 (18)	−0.017 (2)

Geometric parameters (Å, º) top

O16—C6	1.364 (5)	C12—H12A	0.9700
O16—C13	1.381 (3)	C12—H12B	0.9700
C7—C13	1.375 (5)	C14—H14	0.9300
C7—C14	1.399 (4)	C15—H15A	0.9600
C7—C10	1.454 (4)	C15—H15B	0.9600
C8—O1	1.377 (4)	C15—H15C	0.9600
C8—C11	1.385 (6)	C17—C18	1.496 (4)
C8—C9	1.397 (4)	C17—H17A	0.9700
C9—C13	1.379 (5)	C17—H17B	0.9700
C9—H9	0.9300	C18—O3	1.211 (4)
C10—C6	1.365 (6)	C18—O4	1.309 (5)
C10—C17	1.476 (5)	O1—H1	0.8200
C11—C14	1.371 (6)	O2—H2A	0.8499
C11—H11	0.9300	O2—H2B	0.8500
C12—O4	1.448 (4)	O5—H5	0.854 (19)
C12—C15	1.494 (6)	C6—H6	0.9300

C6—O16—C13	106.0 (3)	C11—C14—C7	118.4 (4)
C13—C7—C14	117.7 (3)	C11—C14—H14	120.8
C13—C7—C10	108.0 (3)	C7—C14—H14	120.8
C14—C7—C10	134.2 (4)	C12—C15—H15A	109.5
O1—C8—C11	118.1 (3)	C12—C15—H15B	109.5
O1—C8—C9	120.8 (4)	H15A—C15—H15B	109.5
C11—C8—C9	121.1 (3)	C12—C15—H15C	109.5
C13—C9—C8	114.7 (4)	H15A—C15—H15C	109.5
C13—C9—H9	122.6	H15B—C15—H15C	109.5
C8—C9—H9	122.6	C10—C17—C18	118.0 (3)
C6—C10—C7	103.2 (4)	C10—C17—H17A	107.8
C6—C10—C17	133.3 (3)	C18—C17—H17A	107.8
C7—C10—C17	123.5 (3)	C10—C17—H17B	107.8
C14—C11—C8	122.2 (3)	C18—C17—H17B	107.8
C14—C11—H11	118.9	H17A—C17—H17B	107.1
C8—C11—H11	118.9	O3—C18—O4	124.2 (3)
O4—C12—C15	107.3 (3)	O3—C18—C17	125.6 (4)
O4—C12—H12A	110.3	O4—C18—C17	110.2 (3)
C15—C12—H12A	110.3	C8—O1—H1	109.5
O4—C12—H12B	110.3	H2A—O2—H2B	109.5
C15—C12—H12B	110.3	C18—O4—C12	118.5 (3)
H12A—C12—H12B	108.5	O16—C6—C10	113.5 (3)
C7—C13—C9	125.9 (3)	O16—C6—H6	123.3
C7—C13—O16	109.3 (3)	C10—C6—H6	123.3
C9—C13—O16	124.9 (4)

O1—C8—C9—C13	−179.7 (3)	C6—O16—C13—C9	−179.7 (3)
C11—C8—C9—C13	0.5 (4)	C8—C11—C14—C7	0.0 (4)
C13—C7—C10—C6	−0.6 (3)	C13—C7—C14—C11	1.2 (4)
C14—C7—C10—C6	−178.3 (3)	C10—C7—C14—C11	178.8 (3)
C13—C7—C10—C17	179.3 (3)	C6—C10—C17—C18	−1.7 (5)
C14—C7—C10—C17	1.6 (5)	C7—C10—C17—C18	178.5 (3)
O1—C8—C11—C14	179.3 (3)	C10—C17—C18—O3	−1.1 (5)
C9—C8—C11—C14	−0.9 (5)	C10—C17—C18—O4	179.3 (2)
C14—C7—C13—C9	−1.7 (5)	O3—C18—O4—C12	0.7 (5)
C10—C7—C13—C9	−179.9 (3)	C17—C18—O4—C12	−179.6 (2)
C14—C7—C13—O16	178.4 (2)	C15—C12—O4—C18	−175.7 (3)
C10—C7—C13—O16	0.2 (3)	C13—O16—C6—C10	−0.6 (4)
C8—C9—C13—C7	0.8 (4)	C7—C10—C6—O16	0.7 (4)
C8—C9—C13—O16	−179.3 (3)	C17—C10—C6—O16	−179.2 (3)
C6—O16—C13—C7	0.2 (3)

Hydrogen-bond geometry (Å, º) top

Cg1 is the centroid of the C7/C13/C9/C8/C11/C14 benzene ring and Cg2 is the centroid of the O16/C6/C10/C7/C13 furan ring.

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2	0.82	1.88	2.692 (4)	170
O2—H2A···O3ⁱ	0.85	1.96	2.788 (4)	164
O2—H2B···O5ⁱⁱ	0.85	2.00	2.844 (4)	174
O5—H5···O1ⁱⁱⁱ	0.85 (4)	2.09 (4)	2.870 (3)	152 (4)
C17—H17B···Cg1^iv	0.97	2.68	3.485 (3)	140
C17—H17A···Cg2^v	0.97	2.99	3.889 (3)	154

Symmetry codes: (i) −x+3/2, y−1/2, −z+3/2; (ii) x, −y+2, z+1/2; (iii) −x+1, y, −z+1/2; (iv) −x+1/2, −y+3/2, −z; (v) −x+1/2, −y+1/2, −z.

Hydrogen-bond geometry (Å, º) top

Cg1 is the centroid of the C7/C13/C9/C8/C11/C14 benzene ring and Cg2 is the centroid of the O16/C6/C10/C7/C13 furan ring.

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2	0.82	1.88	2.692 (4)	170
O2—H2A···O3ⁱ	0.85	1.96	2.788 (4)	164
O2—H2B···O5ⁱⁱ	0.85	2.00	2.844 (4)	174
O5—H5···O1ⁱⁱⁱ	0.85 (4)	2.09 (4)	2.870 (3)	152 (4)
C17—H17B···Cg1^iv	0.97	2.68	3.485 (3)	140
C17—H17A···Cg2^v	0.97	2.99	3.889 (3)	154

Symmetry codes: (i) −x+3/2, y−1/2, −z+3/2; (ii) x, −y+2, z+1/2; (iii) −x+1, y, −z+1/2; (iv) −x+1/2, −y+3/2, −z; (v) −x+1/2, −y+1/2, −z.

Experimental details

Crystal data
Chemical formula	2C₁₂H₁₂O₄·3H₂O
M_r	494.48
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	29.191 (6), 7.3291 (17), 12.587 (3)
β (°)	113.074 (13)
V (Å³)	2477.4 (9)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	0.89
Crystal size (mm)	0.47 × 0.34 × 0.26

Data collection
Diffractometer	Bruker APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.730, 0.793
No. of measured, independent and observed [I > 2σ(I)] reflections	8441, 1968, 1132
R_int	0.114
(sin θ/λ)_max (Å⁻¹)	0.584

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.067, 0.224, 1.06
No. of reflections	1968
No. of parameters	168
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.40, −0.54

Computer programs: APEX2 (Bruker, 2009), APEX2 and SAINT-Plus (Bruker, 2009), SAINT-Plus and XPREP (Bruker, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2008).

Acknowledgements

The authors are thankful to the Department of Science and Technology, New Delhi, Government of India, for providing financial assistance under its DST FAST TRACK scheme [SR/FT/CS-81/2010 (G)]. The authors are thankful to the Institution of Excellence, Vijnana Bhavana, University of Mysore, Mysore, for providing the single-crystal X-ray diffraction facility.

References

Arunakumar, D. B., Krishnaswamy, G., Sreenivasa, S., Pampa, K. J., Lokanath, N. K. & Suchetan, P. A. (2014). Acta Cryst. E70, o87. CSD CrossRef IUCr Journals Google Scholar
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Volume 70| Part 12| December 2014| Pages 541-543

doi:10.1107/S1600536814024349

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research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Crystal structure of ethyl (6-hy­dr­oxy-1-benzo­furan-3-yl)acetate sesquihydrate

1. Chemical context

2. Structural commentary

3. Supra­molecular features

4. Synthesis and crystallization

5. Refinement

Supporting information

Acknowledgements

References

research communications

Crystal structure of ethyl (6-hydroxy-1-benzofuran-3-yl)acetate sesquihydrate

3. Supramolecular features