Ethyl 2-[4-(4-chloro­benzo­yl)phen­oxy]-2-methyl­propano­ate

Yang, Z.; Wang, Z.-X.

doi:10.1107/S1600536812021149

organic compounds

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ISSN: 2056-9890

Volume 68| Part 6| June 2012| Page o1750

doi:10.1107/S1600536812021149

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Ethyl 2-[4-(4-chlorobenzoyl)phenoxy]-2-methylpropanoate

Zhao Yang ^a and Zhi-Xiang Wang ^a ^*

^aDepartment of Pharmaceutical Engineering, China Pharmaceutical University, Tongjiaxiang No. 24 Nanjing, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: yzcpu@163.com

(Received 8 May 2012; accepted 9 May 2012; online 16 May 2012)

In the title compound, C₁₉H₁₉ClO₄, the dihedral angle between the mean planes of the benzene rings is 126.8 (1)°. Weak C—H⋯O interactions are observed.

Related literature

For background, see: Guichard et al. (2000 ). For the synthesis of the title compound, see: Bandgar et al., (2011 ). For reference bond-length data, see: Allen et al. (1987 ).

Experimental

Crystal data

C₁₉H₁₉ClO₄
M_r = 346.79
Orthorhombic, P n a 2₁
a = 13.677 (3) Å
b = 16.420 (3) Å
c = 7.9490 (16) Å
V = 1785.2 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.955, T_max = 0.977
3465 measured reflections
3459 independent reflections
1971 reflections with I > 2σ(I)
R_int = 0.058

Refinement

R[F² > 2σ(F²)] = 0.068
wR(F²) = 0.180
S = 1.00
3459 reflections
218 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.21 e Å⁻³
Absolute structure: Flack (1983 ), with 1692 Friedel pairs
Flack parameter: 0.04 (17)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O3ⁱ	0.93	2.54	3.340 (7)	144
Symmetry code: (i) x, y, z-1.

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1989 ); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812021149/jj2137sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812021149/jj2137Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812021149/jj2137Isup3.cml

checkCIF report

Comment top

The title compound, C₂₀H₂₁ClO₄, (I), is Fenofibrate, an antihypertensive drug (Guichard et al. 2000). We report herein its crystal structure.

In the title compound, (I), the dihedral angle between the mean planes of the benzene and phenyl rings is 126.8 (1)°. Crystal packing is influenced by weak C—H···O intermolecular interactions. Bond lengths are in normal ranges (Allen et al. 1987).

Related literature top

For background, see: Guichard et al. (2000). For the synthesis of the title compound, see: Bandgar et al., (2011). For reference bond-length data, see: Allen et al. (1987).

Experimental top

2-(4-(4-chlorobenzoyl)phenoxy)-2-methylpropanoic acid (6.28 mmol, 2.00 g) was dissolved in 35% hydrochloric acid ethanol solution (15 ml), the solution was heated to 338.15 K under N₂ atmosphere for 3 h. The reaction mexture was cooled to room temperature and the solvent was distilled to get the crude compound. The crude compond was dissolved in dichloromethane (15 ml), washed with water (10 ml) three times, dried, and concentrated to get the title compound (1.95 g). pure: white solid (Bandgar et al. 2011). Crystals of the title compound suitable for X-ray diffraction were obtained by slow evaporation of an ethanol solution.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1989); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound, (I), showing the atom-labeling scheme and 50% probability displacement ellipsoids.
	Fig. 2. Packing diagram of the title compound viewed along the a axis. Dashed lines indicate weak C—H···O intermolecular interactions. Remaining H atoms have been omitted for clarity.

Ethyl 2-[4-(4-chlorobenzoyl)phenoxy]-2-methylpropanoate top

Crystal data top

C₁₉H₁₉ClO₄	F(000) = 728
M_r = 346.79	D_x = 1.290 Mg m⁻³
Orthorhombic, Pna2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 25 reflections
a = 13.677 (3) Å	θ = 9–12°
b = 16.420 (3) Å	µ = 0.23 mm⁻¹
c = 7.9490 (16) Å	T = 293 K
V = 1785.2 (6) Å³	Block, colourless
Z = 4	0.20 × 0.20 × 0.10 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	3459 independent reflections
Radiation source: fine-focus sealed tube	1971 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.058
Detector resolution: 16.0355 pixels mm^-1	θ_max = 25.4°, θ_min = 2.5°
ω/2θ scans	h = 0→16
Absorption correction: ψ scan (North et al., 1968)	k = −19→19
T_min = 0.955, T_max = 0.977	l = 0→9
3465 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.068	w = 1/[σ²(F_o²) + (0.078P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.180	(Δ/σ)_max < 0.001
S = 1.00	Δρ_max = 0.21 e Å⁻³
3459 reflections	Δρ_min = −0.21 e Å⁻³
218 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.029 (3)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), with 1692 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.04 (17)

Crystal data top

C₁₉H₁₉ClO₄	V = 1785.2 (6) Å³
M_r = 346.79	Z = 4
Orthorhombic, Pna2₁	Mo Kα radiation
a = 13.677 (3) Å	µ = 0.23 mm⁻¹
b = 16.420 (3) Å	T = 293 K
c = 7.9490 (16) Å	0.20 × 0.20 × 0.10 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	3459 independent reflections
Absorption correction: ψ scan (North et al., 1968)	1971 reflections with I > 2σ(I)
T_min = 0.955, T_max = 0.977	R_int = 0.058
3465 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.068	H-atom parameters constrained
wR(F²) = 0.180	Δρ_max = 0.21 e Å⁻³
S = 1.00	Δρ_min = −0.21 e Å⁻³
3459 reflections	Absolute structure: Flack (1983), with 1692 Friedel pairs
218 parameters	Absolute structure parameter: 0.04 (17)
1 restraint

Special details top

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 > 2sigma(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
Cl	0.48890 (13)	0.70175 (10)	0.0275 (3)	0.1012 (7)
O1	0.5732 (3)	0.8850 (3)	0.7608 (6)	0.0837 (13)
C1	0.4206 (4)	0.8448 (3)	0.4133 (8)	0.0591 (15)
H1A	0.3735	0.8840	0.4365	0.071*
O2	0.1445 (2)	0.96725 (19)	1.0184 (5)	0.0586 (10)
C2	0.4204 (4)	0.8080 (3)	0.2568 (8)	0.0679 (17)
H2A	0.3747	0.8228	0.1757	0.081*
O3	0.2113 (3)	0.9435 (2)	1.3404 (6)	0.0726 (13)
C3	0.4895 (4)	0.7489 (3)	0.2235 (9)	0.0654 (17)
O4	0.2075 (3)	1.0773 (2)	1.3897 (5)	0.0620 (11)
C4	0.5574 (4)	0.7267 (3)	0.3426 (9)	0.0690 (19)
H4A	0.6030	0.6861	0.3196	0.083*
C5	0.5571 (4)	0.7653 (3)	0.4965 (9)	0.0629 (16)
H5A	0.6041	0.7510	0.5757	0.075*
C6	0.4886 (3)	0.8254 (3)	0.5378 (9)	0.0513 (13)
C7	0.4929 (3)	0.8691 (3)	0.7002 (7)	0.0536 (14)
C8	0.4017 (4)	0.8941 (3)	0.7865 (7)	0.0520 (14)
C9	0.4053 (4)	0.9562 (3)	0.9038 (8)	0.0574 (15)
H9A	0.4650	0.9809	0.9267	0.069*
C10	0.3229 (4)	0.9827 (3)	0.9882 (7)	0.0573 (14)
H10A	0.3272	1.0245	1.0668	0.069*
C11	0.2338 (4)	0.9463 (3)	0.9542 (7)	0.0479 (13)
C12	0.2301 (4)	0.8814 (3)	0.8440 (7)	0.0541 (14)
H12A	0.1711	0.8545	0.8270	0.065*
C13	0.3114 (4)	0.8558 (3)	0.7596 (8)	0.0580 (15)
H13A	0.3069	0.8128	0.6839	0.070*
C14	0.1328 (4)	1.0324 (3)	1.1404 (7)	0.0509 (13)
C15	0.1562 (4)	1.1156 (3)	1.0644 (7)	0.0706 (17)
H15A	0.2247	1.1185	1.0390	0.106*
H15B	0.1395	1.1575	1.1434	0.106*
H15C	0.1191	1.1229	0.9630	0.106*
C16	0.0242 (4)	1.0277 (3)	1.1840 (8)	0.0731 (18)
H16A	0.0101	0.9757	1.2338	0.110*
H16B	−0.0139	1.0342	1.0834	0.110*
H16C	0.0081	1.0702	1.2621	0.110*
C17	0.1892 (3)	1.0110 (3)	1.3001 (7)	0.0512 (13)
C18	0.2573 (5)	1.0655 (4)	1.5498 (9)	0.0796 (19)
H18A	0.3151	1.0322	1.5333	0.096*
H18B	0.2144	1.0374	1.6278	0.096*
C19	0.2854 (5)	1.1450 (4)	1.6197 (10)	0.098 (2)
H19A	0.3193	1.1372	1.7241	0.148*
H19B	0.2278	1.1771	1.6389	0.148*
H19C	0.3274	1.1727	1.5416	0.148*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl	0.1114 (14)	0.0824 (11)	0.1098 (14)	0.0005 (9)	0.0354 (14)	−0.0362 (12)
O1	0.045 (2)	0.118 (3)	0.088 (3)	−0.003 (2)	−0.003 (2)	−0.001 (3)
C1	0.054 (3)	0.048 (3)	0.075 (4)	0.009 (3)	0.010 (3)	−0.003 (3)
O2	0.045 (2)	0.072 (2)	0.059 (2)	0.0055 (16)	−0.002 (2)	−0.022 (2)
C2	0.073 (4)	0.055 (3)	0.076 (4)	0.008 (3)	0.015 (4)	−0.004 (3)
O3	0.084 (3)	0.049 (2)	0.085 (3)	0.002 (2)	−0.023 (2)	0.003 (2)
C3	0.059 (4)	0.053 (3)	0.084 (4)	0.000 (3)	0.025 (4)	−0.004 (3)
O4	0.073 (3)	0.060 (2)	0.053 (2)	0.002 (2)	−0.013 (2)	−0.009 (2)
C4	0.052 (3)	0.049 (3)	0.106 (6)	0.007 (3)	0.034 (4)	0.005 (4)
C5	0.049 (3)	0.057 (3)	0.082 (5)	0.013 (3)	0.018 (4)	0.020 (4)
C6	0.038 (3)	0.048 (3)	0.068 (4)	0.001 (2)	0.014 (3)	0.015 (3)
C7	0.040 (3)	0.060 (3)	0.061 (4)	0.003 (2)	0.003 (3)	0.012 (3)
C8	0.045 (3)	0.052 (3)	0.059 (4)	0.002 (2)	−0.002 (3)	0.000 (3)
C9	0.040 (3)	0.068 (3)	0.064 (4)	−0.009 (3)	−0.006 (3)	0.007 (3)
C10	0.055 (3)	0.062 (3)	0.055 (4)	−0.007 (3)	−0.003 (3)	−0.012 (3)
C11	0.044 (3)	0.055 (3)	0.044 (3)	−0.001 (2)	−0.001 (3)	0.000 (3)
C12	0.041 (3)	0.057 (3)	0.065 (4)	−0.007 (2)	0.003 (3)	−0.020 (3)
C13	0.052 (3)	0.056 (3)	0.066 (4)	−0.007 (2)	0.002 (3)	−0.019 (3)
C14	0.049 (3)	0.055 (3)	0.048 (3)	0.001 (2)	−0.003 (3)	−0.008 (3)
C15	0.084 (4)	0.065 (3)	0.063 (4)	0.015 (3)	−0.010 (3)	0.007 (3)
C16	0.054 (4)	0.085 (4)	0.080 (5)	0.012 (3)	0.000 (3)	−0.027 (4)
C17	0.048 (3)	0.057 (3)	0.048 (3)	0.000 (3)	−0.002 (3)	−0.011 (3)
C18	0.103 (5)	0.078 (4)	0.058 (4)	−0.012 (4)	−0.029 (4)	0.004 (4)
C19	0.105 (5)	0.103 (5)	0.088 (5)	−0.029 (4)	−0.012 (5)	−0.024 (5)

Geometric parameters (Å, º) top

Cl—C3	1.740 (7)	C9—H9A	0.9300
O1—C7	1.227 (6)	C10—C11	1.383 (7)
C1—C2	1.383 (8)	C10—H10A	0.9300
C1—C6	1.395 (7)	C11—C12	1.380 (7)
C1—H1A	0.9300	C12—C13	1.365 (7)
O2—C11	1.369 (6)	C12—H12A	0.9300
O2—C14	1.452 (6)	C13—H13A	0.9300
C2—C3	1.380 (7)	C14—C17	1.527 (7)
C2—H2A	0.9300	C14—C15	1.527 (7)
O3—C17	1.192 (6)	C14—C16	1.527 (7)
C3—C4	1.376 (8)	C15—H15A	0.9600
O4—C17	1.325 (6)	C15—H15B	0.9600
O4—C18	1.457 (7)	C15—H15C	0.9600
C4—C5	1.378 (8)	C16—H16A	0.9600
C4—H4A	0.9300	C16—H16B	0.9600
C5—C6	1.399 (7)	C16—H16C	0.9600
C5—H5A	0.9300	C18—C19	1.470 (7)
C6—C7	1.478 (8)	C18—H18A	0.9700
C7—C8	1.482 (7)	C18—H18B	0.9700
C8—C9	1.382 (7)	C19—H19A	0.9600
C8—C13	1.401 (7)	C19—H19B	0.9600
C9—C10	1.382 (7)	C19—H19C	0.9600

C2—C1—C6	122.7 (5)	C11—C12—H12A	119.4
C2—C1—H1A	118.7	C12—C13—C8	120.3 (5)
C6—C1—H1A	118.7	C12—C13—H13A	119.8
C11—O2—C14	122.2 (4)	C8—C13—H13A	119.8
C3—C2—C1	118.5 (6)	O2—C14—C17	109.3 (4)
C3—C2—H2A	120.7	O2—C14—C15	111.8 (5)
C1—C2—H2A	120.7	C17—C14—C15	115.4 (4)
C4—C3—C2	121.2 (6)	O2—C14—C16	102.8 (4)
C4—C3—Cl	120.1 (4)	C17—C14—C16	106.9 (5)
C2—C3—Cl	118.8 (5)	C15—C14—C16	109.8 (4)
C17—O4—C18	116.6 (4)	C14—C15—H15A	109.5
C3—C4—C5	119.1 (5)	C14—C15—H15B	109.5
C3—C4—H4A	120.5	H15A—C15—H15B	109.5
C5—C4—H4A	120.5	C14—C15—H15C	109.5
C4—C5—C6	122.4 (6)	H15A—C15—H15C	109.5
C4—C5—H5A	118.8	H15B—C15—H15C	109.5
C6—C5—H5A	118.8	C14—C16—H16A	109.5
C1—C6—C5	116.2 (6)	C14—C16—H16B	109.5
C1—C6—C7	122.4 (4)	H16A—C16—H16B	109.5
C5—C6—C7	121.4 (5)	C14—C16—H16C	109.5
O1—C7—C6	118.8 (5)	H16A—C16—H16C	109.5
O1—C7—C8	120.8 (5)	H16B—C16—H16C	109.5
C6—C7—C8	120.3 (5)	O3—C17—O4	124.9 (5)
C9—C8—C13	117.7 (5)	O3—C17—C14	124.4 (5)
C9—C8—C7	119.1 (5)	O4—C17—C14	110.7 (4)
C13—C8—C7	123.1 (5)	O4—C18—C19	109.5 (5)
C10—C9—C8	122.0 (5)	O4—C18—H18A	109.8
C10—C9—H9A	119.0	C19—C18—H18A	109.8
C8—C9—H9A	119.0	O4—C18—H18B	109.8
C9—C10—C11	119.2 (5)	C19—C18—H18B	109.8
C9—C10—H10A	120.4	H18A—C18—H18B	108.2
C11—C10—H10A	120.4	C18—C19—H19A	109.5
O2—C11—C12	113.4 (4)	C18—C19—H19B	109.5
O2—C11—C10	127.2 (5)	H19A—C19—H19B	109.5
C12—C11—C10	119.3 (5)	C18—C19—H19C	109.5
C13—C12—C11	121.3 (5)	H19A—C19—H19C	109.5
C13—C12—H12A	119.4	H19B—C19—H19C	109.5

C6—C1—C2—C3	0.9 (8)	C14—O2—C11—C12	178.2 (5)
C1—C2—C3—C4	0.0 (8)	C14—O2—C11—C10	−1.9 (8)
C1—C2—C3—Cl	179.4 (4)	C9—C10—C11—O2	−176.3 (5)
C2—C3—C4—C5	−1.2 (8)	C9—C10—C11—C12	3.6 (8)
Cl—C3—C4—C5	179.5 (4)	O2—C11—C12—C13	175.6 (5)
C3—C4—C5—C6	1.5 (8)	C10—C11—C12—C13	−4.4 (8)
C2—C1—C6—C5	−0.6 (7)	C11—C12—C13—C8	1.6 (9)
C2—C1—C6—C7	175.4 (5)	C9—C8—C13—C12	1.8 (8)
C4—C5—C6—C1	−0.6 (7)	C7—C8—C13—C12	179.5 (5)
C4—C5—C6—C7	−176.7 (5)	C11—O2—C14—C17	−62.1 (6)
C1—C6—C7—O1	−140.2 (5)	C11—O2—C14—C15	66.9 (6)
C5—C6—C7—O1	35.6 (7)	C11—O2—C14—C16	−175.4 (5)
C1—C6—C7—C8	39.0 (7)	C18—O4—C17—O3	−0.7 (8)
C5—C6—C7—C8	−145.2 (5)	C18—O4—C17—C14	177.4 (5)
O1—C7—C8—C9	20.4 (7)	O2—C14—C17—O3	−22.5 (7)
C6—C7—C8—C9	−158.8 (5)	C15—C14—C17—O3	−149.5 (5)
O1—C7—C8—C13	−157.2 (5)	C16—C14—C17—O3	88.1 (6)
C6—C7—C8—C13	23.5 (7)	O2—C14—C17—O4	159.4 (4)
C13—C8—C9—C10	−2.5 (8)	C15—C14—C17—O4	32.4 (6)
C7—C8—C9—C10	179.7 (5)	C16—C14—C17—O4	−90.0 (5)
C8—C9—C10—C11	−0.2 (8)	C17—O4—C18—C19	171.2 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O3ⁱ	0.93	2.54	3.340 (7)	144

Symmetry code: (i) x, y, z−1.

Experimental details

Crystal data
Chemical formula	C₁₉H₁₉ClO₄
M_r	346.79
Crystal system, space group	Orthorhombic, Pna2₁
Temperature (K)	293
a, b, c (Å)	13.677 (3), 16.420 (3), 7.9490 (16)
V (Å³)	1785.2 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.23
Crystal size (mm)	0.20 × 0.20 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.955, 0.977
No. of measured, independent and observed [I > 2σ(I)] reflections	3465, 3459, 1971
R_int	0.058
(sin θ/λ)_max (Å⁻¹)	0.603

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.068, 0.180, 1.00
No. of reflections	3459
No. of parameters	218
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.21
Absolute structure	Flack (1983), with 1692 Friedel pairs
Absolute structure parameter	0.04 (17)

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL-Plus (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O3ⁱ	0.93	2.54	3.340 (7)	144

Symmetry code: (i) x, y, z−1.

Acknowledgements

The authors thank the Center of Testing and Analysis, Nanjing University, for support.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Bandgar, B. P., Sarangdhar, R. J., Khan, F., Mookkan, J., Shetty, P. & Singh, G. (2011). J. Med. Chem. 54, 5915–5926. Web of Science CrossRef CAS PubMed Google Scholar
Enraf–Nonius (19894). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Guichard, J. P., Blouquin, P. & Qing, Y. (2000). Curr. Med. Res. Opin. 16, 134–138. Web of Science CrossRef PubMed CAS Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar