Ethyl 2-{[5-(3-chloro­phen­yl)-1-phenyl-1H-pyrazol-3-yl]­oxy}acetate

Yang, X.-L.

doi:10.1107/S1600536811052937

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 1| January 2012| Page o123

doi:10.1107/S1600536811052937

Open

access

Ethyl 2-{[5-(3-chlorophenyl)-1-phenyl-1H-pyrazol-3-yl]oxy}acetate

Xiao-Li Yang ^a ^*

^aDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: yangxl@jit.edu.cn

(Received 13 November 2011; accepted 8 December 2011; online 14 December 2011)

The title compound, C₁₉H₁₇ClN₂O₃, was synthesized by the reaction of 5-(3-chlorophenyl)-1-phenyl-1H-pyrazol-3-ol and ethyl 2-bromoacetate. In the crystal, the C- and N-linked benzene rings are twisted by 45.15 (3) and 53.55 (3)°, respectively, from the plane of the bridging 1H-pyrazole ring.

Related literature

For 1H-pyrazol-3-oxy derivatives, see: Li et al. (2010 ). For alkyloxyacetates as bioactive groups, see: Tohyama & Sanemitsu (2001 ). For bond-length data, see: Allen et al. (1987 ). For the synthetic procedure, see: Liu et al. (2011 );

Experimental

Crystal data

C₁₉H₁₇ClN₂O₃
M_r = 356.80
Orthorhombic, P b c a
a = 11.6158 (11) Å
b = 15.9119 (16) Å
c = 19.302 (2) Å
V = 3567.6 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 293 K
0.30 × 0.30 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.933, T_max = 0.977
6360 measured reflections
3244 independent reflections
1787 reflections with I > 2σ(I)
R_int = 0.092
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.055
wR(F²) = 0.093
S = 1.01
3244 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ); 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 (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811052937/ez2274sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811052937/ez2274Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811052937/ez2274Isup3.cml

checkCIF report

Comment top

Since the discovery of the strobilurin fungicide pyraclostrobin by BASF scientists, 1H-pyrazol-3-oxy derivatives have attracted considerable attention in chemical and medicinal research because of their low mammalian toxicity and diverse bioactivities (Li et al., 2010). Furthermore, several biological studies have also pointed out the value of alkyloxyacetates (Tohyama & Sanemitsu, 2001) as bioactive groups. Recently, focusing on incorporating an alkyloxyacetate group into 1H-pyrazol-3-oxy derivatives in the hope of obtaining compounds with potential bioactivities, we report here the crystal structure of the title compound (I).

In the molecule of I (Fig.1) the bond lengths (Allen et al., 1987) and angles are within normal ranges. The C-linked benzene ring A (C1—C6) and N-linked benzene ring B (C10—C15) are twisted 45.15 (3)° and 53.55 (3)° from the plane of the bridge 1H-pyrazol ring (N2/N3/C7—C8), respectively. Rings A and B are, of course, planar and the dihedral angle between them is 61.11 (3)°.

Related literature top

For 1H-pyrazol-3-oxy derivatives, see: Li et al. (2010). For alkyloxyacetates as bioactive groups, see: Tohyama & Sanemitsu (2001). For bond-length data, see: Allen et al. (1987). For the synthetic procedure, see: Liu et al. (2011);

Experimental top

The title compound was prepared by the literature method (Liu et al., 2011). Crystals suitable for X-ray analysis were obtained by dissolving I (0.5 g) in ethyl acetate (25 ml) and evaporating the solvent slowly at room temperature for about 10 d.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); 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 (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Ethyl 2-{[5-(3-chlorophenyl)-1-phenyl-1H-pyrazol-3-yl]oxy}acetate top

Crystal data top

C₁₉H₁₇ClN₂O₃	D_x = 1.329 Mg m⁻³
M_r = 356.80	Melting point: 369 K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 25 reflections
a = 11.6158 (11) Å	θ = 10–13°
b = 15.9119 (16) Å	µ = 0.23 mm⁻¹
c = 19.302 (2) Å	T = 293 K
V = 3567.6 (6) Å³	Block, colourless
Z = 8	0.30 × 0.30 × 0.10 mm
F(000) = 1488

Data collection top

Enraf–Nonius CAD-4 diffractometer	1787 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.092
Graphite monochromator	θ_max = 25.4°, θ_min = 2.1°
ω/2θ scans	h = 0→14
Absorption correction: ψ scan (North et al., 1968)	k = 0→19
T_min = 0.933, T_max = 0.977	l = 0→23
6360 measured reflections	3 standard reflections every 200 reflections
3244 independent reflections	intensity decay: 1%

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)] = 0.055	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.093	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.010P)²] where P = (F_o² + 2F_c²)/3
3244 reflections	(Δ/σ)_max < 0.001
226 parameters	Δρ_max = 0.17 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Crystal data top

C₁₉H₁₇ClN₂O₃	V = 3567.6 (6) Å³
M_r = 356.80	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 11.6158 (11) Å	µ = 0.23 mm⁻¹
b = 15.9119 (16) Å	T = 293 K
c = 19.302 (2) Å	0.30 × 0.30 × 0.10 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	1787 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.092
T_min = 0.933, T_max = 0.977	3 standard reflections every 200 reflections
6360 measured reflections	intensity decay: 1%
3244 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.055	0 restraints
wR(F²) = 0.093	H-atom parameters constrained
S = 1.01	Δρ_max = 0.17 e Å⁻³
3244 reflections	Δρ_min = −0.17 e Å⁻³
226 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > 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
Cl	0.35737 (6)	0.17569 (5)	0.39581 (4)	0.0686 (3)
O1	0.00916 (16)	0.53604 (11)	0.21036 (10)	0.0628 (6)
N1	−0.10819 (17)	0.42944 (13)	0.25540 (13)	0.0491 (6)
C1	0.0080 (2)	0.28411 (17)	0.43656 (13)	0.0535 (8)
H1B	−0.0653	0.3054	0.4447	0.064*
N2	−0.08809 (16)	0.36663 (13)	0.30241 (11)	0.0453 (6)
O2	−0.18554 (18)	0.49472 (12)	0.07176 (11)	0.0641 (6)
C2	0.0559 (2)	0.22869 (18)	0.48294 (14)	0.0575 (8)
H2A	0.0148	0.2126	0.5221	0.069*
C3	0.1657 (2)	0.19648 (16)	0.47169 (14)	0.0516 (8)
H3A	0.1989	0.1599	0.5035	0.062*
O3	−0.0121 (2)	0.43762 (13)	0.09175 (12)	0.0896 (8)
C4	0.2242 (2)	0.21959 (16)	0.41286 (14)	0.0450 (7)
C5	0.1774 (2)	0.27566 (16)	0.36660 (13)	0.0421 (7)
H5A	0.2190	0.2917	0.3276	0.050*
C6	0.0677 (2)	0.30848 (16)	0.37803 (13)	0.0417 (7)
C7	0.0204 (2)	0.36878 (17)	0.32760 (13)	0.0423 (6)
C8	0.0733 (2)	0.43603 (16)	0.29721 (14)	0.0506 (7)
H8A	0.1480	0.4552	0.3045	0.061*
C9	−0.0090 (2)	0.46931 (16)	0.25317 (15)	0.0485 (7)
C10	−0.1769 (2)	0.30433 (16)	0.31081 (14)	0.0417 (7)
C11	−0.2865 (2)	0.32957 (17)	0.32679 (13)	0.0478 (7)
H11A	−0.3019	0.3860	0.3351	0.057*
C12	−0.3740 (2)	0.27127 (18)	0.33060 (15)	0.0530 (8)
H12A	−0.4489	0.2883	0.3400	0.064*
C13	−0.3490 (2)	0.18712 (18)	0.32025 (15)	0.0571 (8)
H13A	−0.4074	0.1473	0.3235	0.068*
C14	−0.2385 (2)	0.16216 (18)	0.30514 (15)	0.0590 (8)
H14A	−0.2223	0.1055	0.2987	0.071*
C15	−0.1520 (2)	0.22070 (16)	0.29954 (14)	0.0492 (7)
H15A	−0.0775	0.2041	0.2883	0.059*
C16	−0.0794 (2)	0.55185 (16)	0.16175 (16)	0.0583 (8)
H16A	−0.0667	0.6065	0.1408	0.070*
H16B	−0.1526	0.5538	0.1859	0.070*
C17	−0.0859 (3)	0.48651 (18)	0.10533 (17)	0.0572 (8)
C18	−0.2018 (3)	0.4426 (2)	0.01132 (19)	0.0866 (11)
H18A	−0.2028	0.3837	0.0243	0.104*
H18B	−0.1396	0.4514	−0.0215	0.104*
C19	−0.3146 (4)	0.4671 (3)	−0.0204 (2)	0.1339 (17)
H19A	−0.3283	0.4337	−0.0609	0.201*
H19B	−0.3124	0.5255	−0.0330	0.201*
H19C	−0.3753	0.4580	0.0125	0.201*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl	0.0436 (4)	0.0759 (5)	0.0863 (6)	0.0071 (4)	−0.0079 (4)	0.0128 (5)
O1	0.0566 (12)	0.0455 (11)	0.0863 (15)	−0.0094 (10)	−0.0137 (12)	0.0259 (12)
N1	0.0422 (13)	0.0448 (13)	0.0601 (15)	0.0010 (11)	−0.0036 (11)	0.0165 (14)
C1	0.0543 (18)	0.0535 (18)	0.0527 (17)	0.0112 (15)	0.0052 (16)	0.0014 (17)
N2	0.0385 (12)	0.0426 (13)	0.0549 (15)	−0.0003 (11)	−0.0041 (11)	0.0109 (13)
O2	0.0703 (14)	0.0519 (12)	0.0701 (14)	0.0005 (11)	−0.0086 (13)	−0.0037 (12)
C2	0.071 (2)	0.0544 (19)	0.0469 (17)	0.0013 (17)	0.0090 (16)	0.0051 (17)
C3	0.065 (2)	0.0460 (18)	0.0441 (18)	−0.0032 (15)	−0.0114 (16)	0.0000 (15)
O3	0.0931 (17)	0.0774 (16)	0.0982 (18)	0.0382 (14)	0.0138 (16)	−0.0003 (16)
C4	0.0440 (16)	0.0420 (16)	0.0491 (17)	−0.0059 (13)	−0.0125 (14)	−0.0014 (15)
C5	0.0380 (15)	0.0440 (16)	0.0442 (15)	−0.0095 (12)	−0.0039 (13)	−0.0002 (15)
C6	0.0453 (16)	0.0393 (16)	0.0404 (16)	−0.0041 (13)	−0.0033 (13)	0.0008 (13)
C7	0.0386 (14)	0.0437 (15)	0.0446 (16)	0.0019 (14)	−0.0038 (13)	0.0015 (15)
C8	0.0428 (16)	0.0414 (16)	0.0676 (19)	−0.0053 (14)	−0.0091 (15)	0.0080 (16)
C9	0.0451 (16)	0.0377 (15)	0.0628 (19)	−0.0017 (13)	−0.0007 (16)	0.0104 (16)
C10	0.0382 (15)	0.0425 (16)	0.0444 (16)	−0.0019 (13)	0.0037 (13)	0.0046 (14)
C11	0.0470 (16)	0.0405 (15)	0.0560 (17)	0.0049 (14)	0.0008 (15)	0.0019 (16)
C12	0.0389 (16)	0.063 (2)	0.0577 (19)	0.0015 (15)	0.0088 (15)	0.0056 (18)
C13	0.0544 (18)	0.0512 (19)	0.066 (2)	−0.0127 (16)	−0.0039 (18)	0.0034 (17)
C14	0.0554 (18)	0.0421 (16)	0.079 (2)	−0.0018 (15)	−0.0007 (18)	0.0016 (19)
C15	0.0417 (15)	0.0468 (17)	0.0591 (18)	0.0063 (14)	0.0032 (15)	−0.0018 (16)
C16	0.0614 (19)	0.0359 (16)	0.078 (2)	0.0010 (15)	−0.0115 (18)	0.0153 (18)
C17	0.068 (2)	0.0416 (18)	0.062 (2)	0.0019 (17)	0.0100 (19)	0.0162 (19)
C18	0.111 (3)	0.067 (2)	0.082 (3)	−0.014 (2)	0.002 (2)	−0.013 (2)
C19	0.161 (4)	0.118 (4)	0.122 (4)	−0.023 (3)	−0.041 (4)	−0.019 (3)

Geometric parameters (Å, º) top

Cl—C4	1.729 (3)	C8—C9	1.385 (3)
O1—C9	1.362 (3)	C8—H8A	0.9300
O1—C16	1.415 (3)	C10—C11	1.370 (3)
N1—C9	1.316 (3)	C10—C15	1.379 (3)
N1—N2	1.370 (3)	C11—C12	1.378 (3)
C1—C2	1.374 (3)	C11—H11A	0.9300
C1—C6	1.381 (3)	C12—C13	1.384 (4)
C1—H1B	0.9300	C12—H12A	0.9300
N2—C7	1.351 (3)	C13—C14	1.375 (3)
N2—C10	1.440 (3)	C13—H13A	0.9300
O2—C17	1.333 (3)	C14—C15	1.375 (3)
O2—C18	1.444 (3)	C14—H14A	0.9300
C2—C3	1.391 (4)	C15—H15A	0.9300
C2—H2A	0.9300	C16—C17	1.508 (4)
C3—C4	1.373 (3)	C16—H16A	0.9700
C3—H3A	0.9300	C16—H16B	0.9700
O3—C17	1.188 (3)	C18—C19	1.498 (4)
C4—C5	1.374 (3)	C18—H18A	0.9700
C5—C6	1.394 (3)	C18—H18B	0.9700
C5—H5A	0.9300	C19—H19A	0.9600
C6—C7	1.473 (3)	C19—H19B	0.9600
C7—C8	1.367 (3)	C19—H19C	0.9600

C9—O1—C16	115.3 (2)	C10—C11—C12	120.0 (3)
C9—N1—N2	103.0 (2)	C10—C11—H11A	120.0
C2—C1—C6	120.6 (3)	C12—C11—H11A	120.0
C2—C1—H1B	119.7	C11—C12—C13	119.3 (3)
C6—C1—H1B	119.7	C11—C12—H12A	120.3
C7—N2—N1	112.3 (2)	C13—C12—H12A	120.3
C7—N2—C10	130.2 (2)	C14—C13—C12	120.3 (3)
N1—N2—C10	117.04 (19)	C14—C13—H13A	119.8
C17—O2—C18	116.7 (3)	C12—C13—H13A	119.8
C1—C2—C3	120.4 (3)	C15—C14—C13	120.2 (3)
C1—C2—H2A	119.8	C15—C14—H14A	119.9
C3—C2—H2A	119.8	C13—C14—H14A	119.9
C4—C3—C2	118.9 (3)	C14—C15—C10	119.2 (2)
C4—C3—H3A	120.5	C14—C15—H15A	120.4
C2—C3—H3A	120.5	C10—C15—H15A	120.4
C3—C4—C5	121.0 (2)	O1—C16—C17	113.1 (2)
C3—C4—Cl	119.5 (2)	O1—C16—H16A	109.0
C5—C4—Cl	119.5 (2)	C17—C16—H16A	109.0
C4—C5—C6	120.1 (2)	O1—C16—H16B	109.0
C4—C5—H5A	119.9	C17—C16—H16B	109.0
C6—C5—H5A	119.9	H16A—C16—H16B	107.8
C1—C6—C5	118.9 (2)	O3—C17—O2	125.8 (3)
C1—C6—C7	122.4 (2)	O3—C17—C16	125.1 (3)
C5—C6—C7	118.7 (2)	O2—C17—C16	109.1 (3)
N2—C7—C8	106.6 (2)	O2—C18—C19	107.1 (3)
N2—C7—C6	124.7 (2)	O2—C18—H18A	110.3
C8—C7—C6	128.7 (2)	C19—C18—H18A	110.3
C7—C8—C9	104.6 (2)	O2—C18—H18B	110.3
C7—C8—H8A	127.7	C19—C18—H18B	110.3
C9—C8—H8A	127.7	H18A—C18—H18B	108.5
N1—C9—O1	122.1 (2)	C18—C19—H19A	109.5
N1—C9—C8	113.6 (2)	C18—C19—H19B	109.5
O1—C9—C8	124.3 (2)	H19A—C19—H19B	109.5
C11—C10—C15	120.9 (2)	C18—C19—H19C	109.5
C11—C10—N2	119.3 (2)	H19A—C19—H19C	109.5
C15—C10—N2	119.7 (2)	H19B—C19—H19C	109.5

C9—N1—N2—C7	−0.1 (3)	N2—N1—C9—C8	−0.9 (3)
C9—N1—N2—C10	−172.7 (2)	C16—O1—C9—N1	−8.7 (4)
C6—C1—C2—C3	0.2 (4)	C16—O1—C9—C8	170.3 (3)
C1—C2—C3—C4	−1.3 (4)	C7—C8—C9—N1	1.6 (3)
C2—C3—C4—C5	2.0 (4)	C7—C8—C9—O1	−177.5 (2)
C2—C3—C4—Cl	−176.5 (2)	C7—N2—C10—C11	134.0 (3)
C3—C4—C5—C6	−1.6 (4)	N1—N2—C10—C11	−55.0 (3)
Cl—C4—C5—C6	176.93 (19)	C7—N2—C10—C15	−49.0 (4)
C2—C1—C6—C5	0.2 (4)	N1—N2—C10—C15	122.0 (3)
C2—C1—C6—C7	−179.0 (2)	C15—C10—C11—C12	−1.1 (4)
C4—C5—C6—C1	0.4 (4)	N2—C10—C11—C12	175.8 (2)
C4—C5—C6—C7	179.7 (2)	C10—C11—C12—C13	2.0 (4)
N1—N2—C7—C8	1.0 (3)	C11—C12—C13—C14	−1.1 (5)
C10—N2—C7—C8	172.4 (2)	C12—C13—C14—C15	−0.6 (5)
N1—N2—C7—C6	−178.9 (2)	C13—C14—C15—C10	1.4 (4)
C10—N2—C7—C6	−7.6 (4)	C11—C10—C15—C14	−0.6 (5)
C1—C6—C7—N2	−45.5 (4)	N2—C10—C15—C14	−177.5 (2)
C5—C6—C7—N2	135.3 (3)	C9—O1—C16—C17	−70.7 (3)
C1—C6—C7—C8	134.5 (3)	C18—O2—C17—O3	−3.6 (4)
C5—C6—C7—C8	−44.7 (4)	C18—O2—C17—C16	174.0 (2)
N2—C7—C8—C9	−1.5 (3)	O1—C16—C17—O3	−16.5 (4)
C6—C7—C8—C9	178.5 (2)	O1—C16—C17—O2	165.9 (2)
N2—N1—C9—O1	178.1 (2)	C17—O2—C18—C19	−175.9 (3)

Experimental details

Crystal data
Chemical formula	C₁₉H₁₇ClN₂O₃
M_r	356.80
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	293
a, b, c (Å)	11.6158 (11), 15.9119 (16), 19.302 (2)
V (Å³)	3567.6 (6)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.23
Crystal size (mm)	0.30 × 0.30 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.933, 0.977
No. of measured, independent and observed [I > 2σ(I)] reflections	6360, 3244, 1787
R_int	0.092
(sin θ/λ)_max (Å⁻¹)	0.604

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.055, 0.093, 1.01
No. of reflections	3244
No. of parameters	226
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.17

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

This work was supported by the Industrialization of Scientific Research Promotion Projects of Colleges and Universities in Jiangsu Province. The author also thanks the Center of Testing and Analysis, Nanjing University, for the data collection.

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
Enraf–Nonius (1994). CAD-4 EXPRESS. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
Li, Y., Liu, R., Yan, Z., Zhang, X. & Zhu, H. (2010). Bull. Korean Chem. Soc. 31, 3341–3347. CrossRef CAS Google Scholar
Liu, Y., He, G., Chen, K., Jin, Y., Li, Y. & Zhu, H. (2011). Eur. J. Org. Chem. pp. 5323–5330. Web of Science CSD CrossRef 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
Tohyama, Y. & Sanemitsu, Y. (2001). EP Patent No. 1122244. Google Scholar