Ethyl 4-(2-hydroxy­ethyl­amino)-3-nitro­benzoate

Abdul Rahim, A.S.; Abd Hamid, S.; Narendra Babu, S.N.; Loh, W.-S.; Fun, H.-K.

doi:10.1107/S1600536810008147

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 66| Part 4| April 2010| Pages o846-o847

doi:10.1107/S1600536810008147

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Ethyl 4-(2-hydroxyethylamino)-3-nitrobenzoate

Aisyah Saad Abdul Rahim,^a ‡ Shafida Abd Hamid,^b Shivanagere Nagojappa Narendra Babu,^a Wan-Sin Loh ^c § and Hoong-Kun Fun ^c ^*¶

^aSchool of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bKulliyyah of Science, International Islamic University Malaysia (IIUM), Jalan Istana, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia, and ^cX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: hkfun@usm.my

(Received 25 February 2010; accepted 3 March 2010; online 17 March 2010)

In the title compound, C₁₁H₁₄N₂O₅, the molecular structure is stabilized by an intramolecular N—H⋯O hydrogen bond, which generates an S(6) ring motif. The nitro group is twisted slightly from the attached benzene ring, forming a dihedral angle of 5.2 (2)°. In the crystal packing, intermolecular O—H⋯O and C—H⋯O hydrogen bonds link the molecules into a three-dimensional network. The crystal studied was a non-merohedral twin, the refined ratio of the twin components being 0.264 (2):0.736 (2).

Related literature

For background to benzimidazoles, see: Mayer et al. (1998 ); Brouillette et al. (1999 ); Williams et al. (1995 ); Wright (1951 ). For reference bond-length data, see: Allen et al. (1987 ). For related structures, see: Narendra Babu, Abdul Rahim, Abd Hamid et al. (2009 ); Narendra Babu, Abdul Rahim, Osman et al. (2009 ). For hydrogen-bond motifs, see: Bernstein et al. (1995 ). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ).

Experimental

Crystal data

C₁₁H₁₄N₂O₅
M_r = 254.24
Monoclinic, P 2₁ /c
a = 10.6422 (6) Å
b = 14.9954 (9) Å
c = 7.1975 (4) Å
β = 99.607 (2)°
V = 1132.50 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 100 K
0.43 × 0.13 × 0.03 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 209 0) T_min = 0.951, T_max = 0.997
8457 measured reflections
2587 independent reflections
2026 reflections with I > 2σ(I)
R_int = 0.050

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.129
S = 1.04
2587 reflections
173 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯O2	0.84 (3)	1.99 (3)	2.642 (2)	134 (2)
O5—H5B⋯O3ⁱ	0.83 (3)	2.02 (3)	2.851 (2)	177 (3)
C8—H8A⋯O5ⁱⁱ	0.97	2.51	3.271 (3)	135
C10—H10A⋯O5ⁱⁱⁱ	0.97	2.54	3.267 (3)	132
C10—H10B⋯O1^iv	0.97	2.43	3.168 (3)	133
C11—H11A⋯O2^v	0.97	2.59	3.403 (3)	142
Symmetry codes: (i) $[x+1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (ii) x-1, y, z; (iii) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (iv) $[-x+1, y+{\script{1\over 2}}, -z+{\script{5\over 2}}]$ ; (v) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

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 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810008147/wn2377sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810008147/wn2377Isup2.hkl

checkCIF report

Comment top

Benzimidazoles serve as a common scaffold used worldwide for various successful drugs (Mayer et al., 1998). Construction of pharmacologically important benzimidazoles could be accessed via nitrobenzoic acid precursors (Brouillette et al., 1999; Williams et al., 1995; Wright, 1951). The title compound was obtained as an intermediate in the synthesis of benzimidazole derivatives; we present here its crystal structure.

In the title compound (Fig. 1), the molecular structure is stabilized by an intramolecular N2—H2A···O2 hydrogen bond which generates an S(6) ring motif (Bernstein et al., 1995). The nitro group is slightly twisted away from the benzene ring, the dihedral angle between N1/O1/O2/C2 and C1–C6 being 5.2 (2)°. The bond lengths (Allen et al., 1987) and angles in the molecule are within normal ranges and are similiar to those in other related structures (Narendra Babu, Abdul Rahim, Abd Hamid et al., 2009; Narendra Babu, Abdul Rahim, Osman et al., 2009).

In the crystal packing (Fig. 2), intermolecular O5—H5B···O3, C8—H8A···O5, C10—H10A···O5, C10—H10B···O1 and C11—H11A···O2 hydrogen bonds (Table 1) link the molecules into a three-dimensional network.

Related literature top

For background to benzimidazoles, see: Mayer et al. (1998); Brouillette et al. (1999); Williams et al. (1995); Wright (1951). For reference bond-length data, see: Allen et al. (1987). For related structures, see: Narendra Babu, Abdul Rahim, Abd Hamid et al. (2009); Narendra Babu, Abdul Rahim, Osman et al. (2009). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental top

The synthesis of the title compound was performed by the dropwise addition of N,N-diisopropyl ethylamine (1.1 mmol) to a stirred solution of ethyl 4-fluoro-3-nitrobenzoate (1.0 mmol) in dry dichloromethane (10.0 ml), followed by ethanolamine (1.1 mmol). The reaction mixture was left stirring overnight at room temperature under an inert atmosphere. Upon completion, the reaction mixture was washed with 10% Na₂CO₃ (3 x 10.0 ml). The combined organic fractions were dried over MgSO₄ and evaporated in vacuo. Recrystallisation with hot hexane gave the title compound as bright yellow crystals, which were found to be suitable for characterisation by X-ray crystallography.

Computing details top

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

Figures top

	Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme. Hydrogen atoms are shown as spheres of arbitrary radius. The dashed line indicates an intramolecular hydrogen bond.
	Fig. 2. The crystal packing of the title compound, viewed along the c axis. H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.

Ethyl 4-(2-hydroxyethylamino)-3-nitrobenzoate top

Crystal data top

C₁₁H₁₄N₂O₅	F(000) = 536
M_r = 254.24	D_x = 1.491 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1880 reflections
a = 10.6422 (6) Å	θ = 2.4–28.1°
b = 14.9954 (9) Å	µ = 0.12 mm⁻¹
c = 7.1975 (4) Å	T = 100 K
β = 99.607 (2)°	Needle, yellow
V = 1132.50 (11) Å³	0.43 × 0.13 × 0.03 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	2587 independent reflections
Radiation source: fine-focus sealed tube	2026 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.050
ϕ and ω scans	θ_max = 27.5°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2090)	h = −13→13
T_min = 0.951, T_max = 0.997	k = −19→19
8457 measured reflections	l = −8→9

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)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.129	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0602P)² + 0.3204P] where P = (F_o² + 2F_c²)/3
2587 reflections	(Δ/σ)_max < 0.001
173 parameters	Δρ_max = 0.50 e Å⁻³
0 restraints	Δρ_min = −0.31 e Å⁻³

Crystal data top

C₁₁H₁₄N₂O₅	V = 1132.50 (11) Å³
M_r = 254.24	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.6422 (6) Å	µ = 0.12 mm⁻¹
b = 14.9954 (9) Å	T = 100 K
c = 7.1975 (4) Å	0.43 × 0.13 × 0.03 mm
β = 99.607 (2)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	2587 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2090)	2026 reflections with I > 2σ(I)
T_min = 0.951, T_max = 0.997	R_int = 0.050
8457 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	0 restraints
wR(F²) = 0.129	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.50 e Å⁻³
2587 reflections	Δρ_min = −0.31 e Å⁻³
173 parameters

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > σ(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
O1	0.38669 (15)	0.04338 (11)	1.1300 (3)	0.0285 (4)
O2	0.57298 (13)	0.09227 (10)	1.2508 (2)	0.0193 (4)
O3	0.04479 (14)	0.22764 (10)	0.8325 (2)	0.0194 (4)
O4	0.07343 (13)	0.37665 (10)	0.8413 (2)	0.0170 (4)
O5	0.82105 (15)	0.33071 (11)	1.0883 (2)	0.0192 (4)
N1	0.46108 (17)	0.10564 (12)	1.1729 (3)	0.0157 (4)
N2	0.61527 (17)	0.26565 (12)	1.2825 (3)	0.0147 (4)
C1	0.29266 (19)	0.20462 (14)	1.0362 (3)	0.0141 (5)
H1A	0.2445	0.1539	0.9998	0.017*
C2	0.4166 (2)	0.19539 (14)	1.1327 (3)	0.0135 (4)
C3	0.49466 (19)	0.27115 (14)	1.1919 (3)	0.0135 (4)
C4	0.43542 (19)	0.35571 (14)	1.1508 (3)	0.0148 (5)
H4A	0.4811	0.4071	1.1901	0.018*
C5	0.3135 (2)	0.36374 (14)	1.0555 (3)	0.0148 (5)
H5A	0.2784	0.4202	1.0308	0.018*
C6	0.2402 (2)	0.28743 (14)	0.9938 (3)	0.0150 (5)
C7	0.11002 (19)	0.29283 (14)	0.8828 (3)	0.0148 (5)
C8	−0.05110 (19)	0.38757 (14)	0.7226 (3)	0.0168 (5)
H8A	−0.1143	0.3517	0.7709	0.020*
H8B	−0.0473	0.3685	0.5949	0.020*
C9	−0.0866 (2)	0.48440 (16)	0.7242 (4)	0.0254 (6)
H9A	−0.1695	0.4929	0.6501	0.038*
H9B	−0.0251	0.5192	0.6722	0.038*
H9C	−0.0879	0.5031	0.8515	0.038*
C10	0.69687 (19)	0.34151 (14)	1.3465 (3)	0.0142 (4)
H10A	0.7673	0.3210	1.4400	0.017*
H10B	0.6484	0.3841	1.4073	0.017*
C11	0.75012 (19)	0.38863 (14)	1.1886 (3)	0.0157 (5)
H11A	0.6801	0.4141	1.1011	0.019*
H11B	0.8047	0.4372	1.2419	0.019*
H2A	0.642 (2)	0.2141 (18)	1.310 (4)	0.021 (7)*
H5B	0.888 (3)	0.3148 (18)	1.156 (4)	0.028 (8)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0224 (8)	0.0119 (8)	0.0480 (12)	−0.0046 (7)	−0.0035 (8)	0.0003 (8)
O2	0.0169 (8)	0.0143 (8)	0.0252 (9)	0.0027 (6)	−0.0004 (7)	0.0010 (7)
O3	0.0145 (7)	0.0177 (8)	0.0243 (9)	−0.0040 (6)	−0.0011 (7)	0.0005 (7)
O4	0.0118 (7)	0.0168 (8)	0.0207 (9)	0.0003 (6)	−0.0024 (6)	0.0005 (7)
O5	0.0149 (8)	0.0216 (9)	0.0204 (9)	0.0025 (6)	0.0012 (7)	−0.0020 (7)
N1	0.0146 (9)	0.0129 (9)	0.0192 (10)	−0.0015 (7)	0.0018 (7)	−0.0009 (8)
N2	0.0116 (8)	0.0115 (9)	0.0201 (10)	0.0007 (7)	0.0002 (8)	0.0017 (8)
C1	0.0153 (11)	0.0145 (10)	0.0130 (11)	−0.0038 (8)	0.0036 (8)	−0.0026 (9)
C2	0.0151 (10)	0.0119 (10)	0.0144 (11)	−0.0002 (8)	0.0051 (8)	0.0017 (8)
C3	0.0145 (10)	0.0142 (11)	0.0118 (11)	−0.0018 (8)	0.0029 (8)	−0.0001 (8)
C4	0.0135 (10)	0.0123 (10)	0.0188 (12)	−0.0012 (8)	0.0030 (8)	−0.0016 (9)
C5	0.0169 (10)	0.0128 (10)	0.0147 (11)	0.0014 (8)	0.0027 (8)	0.0010 (9)
C6	0.0132 (10)	0.0165 (11)	0.0156 (11)	0.0003 (8)	0.0030 (9)	0.0013 (9)
C7	0.0148 (10)	0.0159 (11)	0.0144 (11)	−0.0004 (8)	0.0045 (9)	0.0007 (9)
C8	0.0116 (10)	0.0203 (11)	0.0161 (11)	0.0004 (8)	−0.0045 (9)	0.0015 (9)
C9	0.0198 (11)	0.0226 (13)	0.0301 (14)	0.0053 (9)	−0.0069 (10)	−0.0019 (11)
C10	0.0116 (9)	0.0147 (10)	0.0148 (11)	−0.0009 (8)	−0.0017 (8)	−0.0004 (9)
C11	0.0127 (10)	0.0128 (10)	0.0208 (11)	−0.0013 (8)	0.0005 (9)	−0.0004 (9)

Geometric parameters (Å, º) top

O1—N1	1.230 (2)	C4—C5	1.368 (3)
O2—N1	1.245 (2)	C4—H4A	0.9300
O3—C7	1.218 (3)	C5—C6	1.414 (3)
O4—C7	1.335 (3)	C5—H5A	0.9300
O4—C8	1.461 (2)	C6—C7	1.482 (3)
O5—C11	1.424 (3)	C8—C9	1.501 (3)
O5—H5B	0.83 (3)	C8—H8A	0.9700
N1—C2	1.440 (3)	C8—H8B	0.9700
N2—C3	1.342 (3)	C9—H9A	0.9600
N2—C10	1.459 (3)	C9—H9B	0.9600
N2—H2A	0.84 (3)	C9—H9C	0.9600
C1—C6	1.375 (3)	C10—C11	1.526 (3)
C1—C2	1.391 (3)	C10—H10A	0.9700
C1—H1A	0.9300	C10—H10B	0.9700
C2—C3	1.430 (3)	C11—H11A	0.9700
C3—C4	1.425 (3)	C11—H11B	0.9700

C7—O4—C8	116.01 (16)	O3—C7—C6	123.46 (19)
C11—O5—H5B	110 (2)	O4—C7—C6	112.56 (18)
O1—N1—O2	121.21 (17)	O4—C8—C9	107.99 (17)
O1—N1—C2	118.86 (17)	O4—C8—H8A	110.1
O2—N1—C2	119.92 (17)	C9—C8—H8A	110.1
C3—N2—C10	125.21 (19)	O4—C8—H8B	110.1
C3—N2—H2A	115.5 (18)	C9—C8—H8B	110.1
C10—N2—H2A	119.1 (18)	H8A—C8—H8B	108.4
C6—C1—C2	121.12 (19)	C8—C9—H9A	109.5
C6—C1—H1A	119.4	C8—C9—H9B	109.5
C2—C1—H1A	119.4	H9A—C9—H9B	109.5
C1—C2—C3	121.68 (19)	C8—C9—H9C	109.5
C1—C2—N1	116.49 (18)	H9A—C9—H9C	109.5
C3—C2—N1	121.82 (19)	H9B—C9—H9C	109.5
N2—C3—C4	120.65 (19)	N2—C10—C11	113.65 (18)
N2—C3—C2	123.9 (2)	N2—C10—H10A	108.8
C4—C3—C2	115.47 (18)	C11—C10—H10A	108.8
C5—C4—C3	122.1 (2)	N2—C10—H10B	108.8
C5—C4—H4A	118.9	C11—C10—H10B	108.8
C3—C4—H4A	118.9	H10A—C10—H10B	107.7
C4—C5—C6	120.9 (2)	O5—C11—C10	112.94 (18)
C4—C5—H5A	119.5	O5—C11—H11A	109.0
C6—C5—H5A	119.5	C10—C11—H11A	109.0
C1—C6—C5	118.61 (19)	O5—C11—H11B	109.0
C1—C6—C7	118.53 (19)	C10—C11—H11B	109.0
C5—C6—C7	122.85 (19)	H11A—C11—H11B	107.8
O3—C7—O4	123.96 (19)

C6—C1—C2—C3	0.0 (3)	C3—C4—C5—C6	0.3 (3)
C6—C1—C2—N1	178.9 (2)	C2—C1—C6—C5	−1.9 (3)
O1—N1—C2—C1	−3.9 (3)	C2—C1—C6—C7	177.1 (2)
O2—N1—C2—C1	176.5 (2)	C4—C5—C6—C1	1.8 (3)
O1—N1—C2—C3	175.0 (2)	C4—C5—C6—C7	−177.2 (2)
O2—N1—C2—C3	−4.6 (3)	C8—O4—C7—O3	−2.2 (3)
C10—N2—C3—C4	−0.1 (3)	C8—O4—C7—C6	176.60 (18)
C10—N2—C3—C2	−179.3 (2)	C1—C6—C7—O3	2.8 (3)
C1—C2—C3—N2	−178.8 (2)	C5—C6—C7—O3	−178.3 (2)
N1—C2—C3—N2	2.4 (3)	C1—C6—C7—O4	−176.1 (2)
C1—C2—C3—C4	2.0 (3)	C5—C6—C7—O4	2.9 (3)
N1—C2—C3—C4	−176.81 (19)	C7—O4—C8—C9	168.7 (2)
N2—C3—C4—C5	178.7 (2)	C3—N2—C10—C11	−76.3 (3)
C2—C3—C4—C5	−2.1 (3)	N2—C10—C11—O5	−57.4 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O2	0.84 (3)	1.99 (3)	2.642 (2)	134 (2)
O5—H5B···O3ⁱ	0.83 (3)	2.02 (3)	2.851 (2)	177 (3)
C8—H8A···O5ⁱⁱ	0.97	2.51	3.271 (3)	135
C10—H10A···O5ⁱⁱⁱ	0.97	2.54	3.267 (3)	132
C10—H10B···O1^iv	0.97	2.43	3.168 (3)	133
C11—H11A···O2^v	0.97	2.59	3.403 (3)	142

Symmetry codes: (i) x+1, −y+1/2, z+1/2; (ii) x−1, y, z; (iii) x, −y+1/2, z+1/2; (iv) −x+1, y+1/2, −z+5/2; (v) x, −y+1/2, z−1/2.

Experimental details

Crystal data
Chemical formula	C₁₁H₁₄N₂O₅
M_r	254.24
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	10.6422 (6), 14.9954 (9), 7.1975 (4)
β (°)	99.607 (2)
V (Å³)	1132.50 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.43 × 0.13 × 0.03

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2090)
T_min, T_max	0.951, 0.997
No. of measured, independent and observed [I > 2σ(I)] reflections	8457, 2587, 2026
R_int	0.050
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.129, 1.04
No. of reflections	2587
No. of parameters	173
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.31

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O2	0.84 (3)	1.99 (3)	2.642 (2)	134 (2)
O5—H5B···O3ⁱ	0.83 (3)	2.02 (3)	2.851 (2)	177 (3)
C8—H8A···O5ⁱⁱ	0.9700	2.5100	3.271 (3)	135.00
C10—H10A···O5ⁱⁱⁱ	0.97	2.54	3.267 (3)	132.0
C10—H10B···O1^iv	0.9700	2.4300	3.168 (3)	133.00
C11—H11A···O2^v	0.97	2.59	3.403 (3)	141.6

Symmetry codes: (i) x+1, −y+1/2, z+1/2; (ii) x−1, y, z; (iii) x, −y+1/2, z+1/2; (iv) −x+1, y+1/2, −z+5/2; (v) x, −y+1/2, z−1/2.

Footnotes

‡Additional correspondence author, e-mail: aisyah@usm.my.

§Thomson Reuters ResearcherID: C-7581-2009.

¶Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

HKF and WSL thank Universiti Sains Malaysia (USM) for the Research University Golden Goose Grant (1001/PFIZIK/811012). WSL thanks the Malaysian Government and USM for the award of a Research Fellowship. ASAR, SAH and SNNB thank USM for funding the synthetic chemistry work under the University Research Grant (1001/PFARMASI/815026). SNNB acknowledges USM for a post-doctoral research fellowship.

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