(E)-N′-[4-(Dimethyl­amino)­benzyl­idene]-2-meth­oxy­benzohydrazide

Liu, S.-Y.; Wang, X.

doi:10.1107/S1600536810023937

organic compounds

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ISSN: 2056-9890

Volume 66| Part 7| July 2010| Page o1775

doi:10.1107/S1600536810023937

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(E)-N′-[4-(Dimethylamino)benzylidene]-2-methoxybenzohydrazide

Shi-Yong Liu ^a ^* and Xiaoling Wang ^b

^aCollege of Chemistry & Pharmacy, Taizhou University, Taizhou Zhejiang 317000, People's Republic of China, and ^bDepartment of Chemistry, Liaoning Normal University, Dalian 116029, People's Republic of China
^*Correspondence e-mail: liushiyong2010@yahoo.cn

(Received 18 June 2010; accepted 20 June 2010; online 26 June 2010)

In the title compound, C₁₇H₁₉N₃O₂, the two benzene rings form a dihedral angle of 89.2 (2)°. In the crystal structure, molecules are linked through N—H⋯O hydrogen bonds, forming C(4) chains running along the c axis.

Related literature

For the medicinal applications of hydrazone compounds, see: Hillmer et al. (2010 ); Zhu et al. (2009 ); Jimenez-Pulido et al. (2008 ); Raj et al. (2007 ); Zhong et al. (2007 ). For hydrazones we have reported previously, see: Liu & You (2010a ,b ,c ). For the crystal structures of similar hydrazone compounds, see: Khaledi et al. (2009 ); Warad et al. (2009 ); Back et al. (2009 ); Vijayakumar et al. (2009 ). For other related structures, see: Cao (2009 ); Xu et al. (2009 ); Shafiq et al. (2009 ).

Experimental

Crystal data

C₁₇H₁₉N₃O₂
M_r = 297.35
Orthorhombic, P b c a
a = 24.726 (4) Å
b = 15.385 (3) Å
c = 8.2700 (15) Å
V = 3146.0 (10) Å³
Z = 8
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 298 K
0.20 × 0.17 × 0.13 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ) T_min = 0.983, T_max = 0.989
12277 measured reflections
2096 independent reflections
1545 reflections with I > 2σ(I)
R_int = 0.045
θ_max = 22.7°

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.106
S = 1.04
2096 reflections
202 parameters
H-atom parameters constrained
Δρ_max = 0.11 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2ⁱ	0.90	2.03	2.914 (2)	165
Symmetry code: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); 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.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810023937/sj5024sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810023937/sj5024Isup2.hkl

checkCIF report

Comment top

Considerable attention has been focused on hydrazones and their medicinal applications (Hillmer et al., 2010; Zhu et al., 2009; Jimenez-Pulido et al., 2008; Raj et al., 2007; Zhong et al., 2007). The study on the crystal structures of such compounds is of particular interest (Khaledi et al., 2009; Warad et al., 2009; Back et al., 2009; Vijayakumar et al., 2009). As a continuation of our work on such compounds (Liu & You, 2010a,b,c), we report herein the crystal structure of the title new hydrazone.

The molecular structure of the title compound is shown in Fig. 1. The dihedral angle between the C1—C6 and C10—C15 benzene rings is 89.2 (2)°, indicating they are nearly perpendicular to each other. All the bond lengths are comparable to those observed in related structures (Cao, 2009; Xu et al., 2009; Shafiq et al., 2009) and those we reported previously.

In the crystal structure, molecules are linked through N—H···O hydrogen bonds, to form one-dimensional chains running along the c axis (Fig. 2 and Table 1).

Related literature top

For the medicinal applications of hydrazone compounds, see: Hillmer et al. (2010); Zhu et al. (2009); Jimenez-Pulido et al. (2008); Raj et al. (2007); Zhong et al. (2007). For hydrazones we have reported previously, see: Liu & You (2010a,b,c). For the crystal structures of similar hydrazone compounds, see: Khaledi et al. (2009); Warad et al. (2009); Back et al. (2009); Vijayakumar et al. (2009). For other related structures, see: Cao (2009); Xu et al. (2009); Shafiq et al. (2009).

Experimental top

The title compound was prepared by the condensation reaction of 4-dimethylaminobenzaldehyde (0.05 mol, 7.5 g) and 2-methoxybenzohydrazide (0.05 mol, 8.3 g) in anhydrous methanol (200 ml) at ambient temperature. Colourless block-shaped single crystals suitable for X-ray structural determination were obtained by slow evaporation of the solution for a period of 13 d.

Computing details top

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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).

Figures top

	Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms are shown as spheres of arbitrary radius.
	Fig. 2. The molecular packing of the title compound, viewed along the b axis. Hydrogen bonds are shown as dashed lines. Hydrogen atoms not involved in hydrogen bonding have been omitted.

(E)-N'-[4-(Dimethylamino)benzylidene]-2-methoxybenzohydrazide top

Crystal data top

C₁₇H₁₉N₃O₂	D_x = 1.256 Mg m⁻³
M_r = 297.35	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 1881 reflections
a = 24.726 (4) Å	θ = 2.5–24.0°
b = 15.385 (3) Å	µ = 0.08 mm⁻¹
c = 8.2700 (15) Å	T = 298 K
V = 3146.0 (10) Å³	Block, colourless
Z = 8	0.20 × 0.17 × 0.13 mm
F(000) = 1264

Data collection top

Bruker SMART CCD area-detector diffractometer	2096 independent reflections
Radiation source: fine-focus sealed tube	1545 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.045
ω scans	θ_max = 22.7°, θ_min = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −26→26
T_min = 0.983, T_max = 0.989	k = −13→16
12277 measured reflections	l = −8→8

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.106	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0545P)² + 0.2933P] where P = (F_o² + 2F_c²)/3
2096 reflections	(Δ/σ)_max < 0.001
202 parameters	Δρ_max = 0.11 e Å⁻³
0 restraints	Δρ_min = −0.15 e Å⁻³

Crystal data top

C₁₇H₁₉N₃O₂	V = 3146.0 (10) Å³
M_r = 297.35	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 24.726 (4) Å	µ = 0.08 mm⁻¹
b = 15.385 (3) Å	T = 298 K
c = 8.2700 (15) Å	0.20 × 0.17 × 0.13 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	2096 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	1545 reflections with I > 2σ(I)
T_min = 0.983, T_max = 0.989	R_int = 0.045
12277 measured reflections	θ_max = 22.7°

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.106	H-atom parameters constrained
S = 1.04	Δρ_max = 0.11 e Å⁻³
2096 reflections	Δρ_min = −0.15 e Å⁻³
202 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
O1	0.22678 (6)	0.40089 (10)	−0.07729 (18)	0.0681 (5)
O2	0.22007 (6)	0.33552 (10)	0.36694 (18)	0.0635 (5)
N1	0.18746 (6)	0.26778 (11)	0.1458 (2)	0.0497 (5)
H1	0.1951	0.2438	0.0491	0.060*
N2	0.14034 (6)	0.24198 (11)	0.2235 (2)	0.0485 (5)
N3	−0.07797 (7)	0.02776 (13)	0.3833 (2)	0.0649 (5)
C1	0.27573 (9)	0.37736 (13)	−0.0152 (3)	0.0529 (6)
C2	0.27502 (8)	0.33335 (12)	0.1323 (2)	0.0456 (5)
C3	0.32355 (9)	0.30874 (14)	0.2011 (3)	0.0611 (6)
H3	0.3234	0.2808	0.3009	0.073*
C4	0.37239 (10)	0.32468 (17)	0.1251 (4)	0.0754 (8)
H4	0.4047	0.3059	0.1707	0.090*
C5	0.37218 (11)	0.36868 (17)	−0.0186 (4)	0.0784 (8)
H5	0.4048	0.3805	−0.0699	0.094*
C6	0.32491 (11)	0.39565 (17)	−0.0884 (3)	0.0700 (7)
H6	0.3258	0.4264	−0.1852	0.084*
C7	0.22616 (11)	0.44770 (17)	−0.2266 (3)	0.0836 (8)
H7A	0.2432	0.4134	−0.3092	0.125*
H7B	0.2454	0.5014	−0.2138	0.125*
H7C	0.1894	0.4597	−0.2570	0.125*
C8	0.22464 (8)	0.31366 (12)	0.2249 (3)	0.0454 (5)
C9	0.11475 (8)	0.18206 (15)	0.1511 (3)	0.0511 (6)
H9	0.1286	0.1607	0.0545	0.061*
C10	0.06471 (8)	0.14545 (13)	0.2125 (2)	0.0477 (5)
C11	0.04784 (8)	0.06446 (15)	0.1597 (3)	0.0575 (6)
H11	0.0683	0.0359	0.0817	0.069*
C12	0.00212 (8)	0.02449 (15)	0.2177 (3)	0.0595 (6)
H12	−0.0070	−0.0307	0.1808	0.071*
C13	−0.03087 (8)	0.06541 (14)	0.3311 (2)	0.0505 (6)
C14	−0.01414 (8)	0.14694 (15)	0.3850 (3)	0.0578 (6)
H14	−0.0349	0.1759	0.4618	0.069*
C15	0.03229 (8)	0.18573 (14)	0.3275 (3)	0.0559 (6)
H15	0.0421	0.2402	0.3666	0.067*
C16	−0.09234 (10)	−0.05974 (17)	0.3378 (3)	0.0803 (8)
H16A	−0.0627	−0.0981	0.3608	0.120*
H16B	−0.1004	−0.0616	0.2243	0.120*
H16C	−0.1235	−0.0778	0.3981	0.120*
C17	−0.11115 (9)	0.07019 (18)	0.5026 (3)	0.0823 (8)
H17A	−0.1181	0.1290	0.4696	0.124*
H17B	−0.0927	0.0703	0.6048	0.124*
H17C	−0.1448	0.0396	0.5131	0.124*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0796 (12)	0.0712 (11)	0.0536 (10)	−0.0085 (9)	0.0061 (8)	0.0234 (8)
O2	0.0784 (11)	0.0708 (10)	0.0414 (9)	−0.0189 (8)	0.0174 (8)	−0.0065 (8)
N1	0.0541 (10)	0.0541 (11)	0.0409 (10)	−0.0082 (9)	0.0165 (8)	−0.0036 (9)
N2	0.0496 (10)	0.0499 (11)	0.0459 (11)	−0.0043 (9)	0.0139 (8)	0.0023 (9)
N3	0.0521 (12)	0.0772 (14)	0.0653 (13)	−0.0155 (10)	0.0051 (10)	0.0058 (11)
C1	0.0655 (15)	0.0453 (13)	0.0479 (14)	−0.0098 (11)	0.0155 (12)	−0.0028 (11)
C2	0.0550 (14)	0.0359 (11)	0.0458 (13)	−0.0035 (10)	0.0138 (10)	−0.0035 (10)
C3	0.0631 (16)	0.0563 (14)	0.0639 (15)	−0.0020 (12)	0.0095 (13)	−0.0019 (12)
C4	0.0549 (15)	0.0767 (18)	0.095 (2)	−0.0044 (13)	0.0095 (14)	−0.0162 (17)
C5	0.0687 (18)	0.0812 (19)	0.085 (2)	−0.0273 (15)	0.0342 (16)	−0.0231 (17)
C6	0.0837 (19)	0.0681 (16)	0.0581 (16)	−0.0265 (14)	0.0266 (15)	−0.0032 (13)
C7	0.125 (2)	0.0708 (17)	0.0551 (16)	−0.0141 (16)	0.0011 (15)	0.0205 (14)
C8	0.0575 (13)	0.0362 (11)	0.0423 (13)	−0.0011 (10)	0.0121 (11)	0.0031 (10)
C9	0.0520 (13)	0.0587 (14)	0.0425 (13)	−0.0002 (11)	0.0080 (10)	−0.0007 (11)
C10	0.0466 (12)	0.0553 (14)	0.0413 (12)	0.0003 (10)	0.0009 (10)	−0.0011 (11)
C11	0.0540 (14)	0.0641 (15)	0.0545 (14)	−0.0009 (12)	0.0057 (11)	−0.0100 (12)
C12	0.0548 (14)	0.0567 (14)	0.0671 (16)	−0.0072 (12)	−0.0045 (12)	−0.0058 (12)
C13	0.0440 (12)	0.0620 (15)	0.0455 (13)	−0.0029 (11)	−0.0064 (10)	0.0062 (12)
C14	0.0497 (13)	0.0691 (16)	0.0545 (14)	−0.0016 (12)	0.0086 (11)	−0.0074 (12)
C15	0.0547 (13)	0.0534 (13)	0.0597 (14)	−0.0066 (11)	0.0042 (11)	−0.0074 (12)
C16	0.0687 (16)	0.0782 (19)	0.0941 (19)	−0.0233 (14)	−0.0054 (14)	0.0165 (16)
C17	0.0606 (15)	0.114 (2)	0.0728 (17)	−0.0136 (15)	0.0145 (14)	0.0077 (17)

Geometric parameters (Å, º) top

O1—C1	1.363 (2)	C7—H7A	0.9600
O1—C7	1.429 (3)	C7—H7B	0.9600
O2—C8	1.227 (2)	C7—H7C	0.9600
N1—C8	1.331 (2)	C9—C10	1.451 (3)
N1—N2	1.389 (2)	C9—H9	0.9300
N1—H1	0.9002	C10—C11	1.385 (3)
N2—C9	1.269 (2)	C10—C15	1.390 (3)
N3—C13	1.370 (3)	C11—C12	1.373 (3)
N3—C17	1.440 (3)	C11—H11	0.9300
N3—C16	1.442 (3)	C12—C13	1.393 (3)
C1—C6	1.387 (3)	C12—H12	0.9300
C1—C2	1.396 (3)	C13—C14	1.394 (3)
C2—C3	1.381 (3)	C14—C15	1.379 (3)
C2—C8	1.493 (3)	C14—H14	0.9300
C3—C4	1.384 (3)	C15—H15	0.9300
C3—H3	0.9300	C16—H16A	0.9600
C4—C5	1.367 (4)	C16—H16B	0.9600
C4—H4	0.9300	C16—H16C	0.9600
C5—C6	1.368 (4)	C17—H17A	0.9600
C5—H5	0.9300	C17—H17B	0.9600
C6—H6	0.9300	C17—H17C	0.9600

C1—O1—C7	117.94 (17)	N1—C8—C2	115.55 (18)
C8—N1—N2	120.22 (16)	N2—C9—C10	122.83 (19)
C8—N1—H1	120.6	N2—C9—H9	118.6
N2—N1—H1	118.0	C10—C9—H9	118.6
C9—N2—N1	114.06 (16)	C11—C10—C15	116.31 (19)
C13—N3—C17	120.6 (2)	C11—C10—C9	119.73 (19)
C13—N3—C16	121.5 (2)	C15—C10—C9	123.93 (19)
C17—N3—C16	117.47 (19)	C12—C11—C10	122.7 (2)
O1—C1—C6	124.1 (2)	C12—C11—H11	118.6
O1—C1—C2	116.54 (18)	C10—C11—H11	118.6
C6—C1—C2	119.4 (2)	C11—C12—C13	121.0 (2)
C3—C2—C1	118.84 (19)	C11—C12—H12	119.5
C3—C2—C8	117.25 (19)	C13—C12—H12	119.5
C1—C2—C8	123.87 (19)	N3—C13—C12	121.2 (2)
C2—C3—C4	121.5 (2)	N3—C13—C14	122.1 (2)
C2—C3—H3	119.2	C12—C13—C14	116.62 (19)
C4—C3—H3	119.2	C15—C14—C13	121.8 (2)
C5—C4—C3	118.6 (2)	C15—C14—H14	119.1
C5—C4—H4	120.7	C13—C14—H14	119.1
C3—C4—H4	120.7	C14—C15—C10	121.6 (2)
C4—C5—C6	121.3 (2)	C14—C15—H15	119.2
C4—C5—H5	119.3	C10—C15—H15	119.2
C6—C5—H5	119.3	N3—C16—H16A	109.5
C5—C6—C1	120.2 (2)	N3—C16—H16B	109.5
C5—C6—H6	119.9	H16A—C16—H16B	109.5
C1—C6—H6	119.9	N3—C16—H16C	109.5
O1—C7—H7A	109.5	H16A—C16—H16C	109.5
O1—C7—H7B	109.5	H16B—C16—H16C	109.5
H7A—C7—H7B	109.5	N3—C17—H17A	109.5
O1—C7—H7C	109.5	N3—C17—H17B	109.5
H7A—C7—H7C	109.5	H17A—C17—H17B	109.5
H7B—C7—H7C	109.5	N3—C17—H17C	109.5
O2—C8—N1	123.55 (18)	H17A—C17—H17C	109.5
O2—C8—C2	120.81 (19)	H17B—C17—H17C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2ⁱ	0.90	2.03	2.914 (2)	165

Symmetry code: (i) x, −y+1/2, z−1/2.

Experimental details

Crystal data
Chemical formula	C₁₇H₁₉N₃O₂
M_r	297.35
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	298
a, b, c (Å)	24.726 (4), 15.385 (3), 8.2700 (15)
V (Å³)	3146.0 (10)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.20 × 0.17 × 0.13

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.983, 0.989
No. of measured, independent and observed [I > 2σ(I)] reflections	12277, 2096, 1545
R_int	0.045
θ_max (°)	22.7
(sin θ/λ)_max (Å⁻¹)	0.542

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.106, 1.04
No. of reflections	2096
No. of parameters	202
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.11, −0.15

Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2ⁱ	0.90	2.03	2.914 (2)	165.2

Symmetry code: (i) x, −y+1/2, z−1/2.

Acknowledgements

The authors acknowledge Taizhou University for financial support.

References

Back, D. F., Ballin, M. A. & de Oliveira, G. M. (2009). J. Mol. Struct. 935, 151–155. Web of Science CSD CrossRef CAS Google Scholar
Bruker (2001). SADABS. Version 2.03. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cao, G.-B. (2009). Acta Cryst. E65, o2086. Web of Science CSD CrossRef IUCr Journals Google Scholar
Hillmer, A. S., Putcha, P., Levin, J., Hogen, T., Hyman, B. T., Kretzschmar, H., McLean, P. J. & Giese, A. (2010). Biochem. Biophys. Res. Commun. 391, 461–466. Web of Science CrossRef PubMed CAS Google Scholar
Jimenez-Pulido, S. B., Linares-Ordonez, F. M., Martinez-Martos, J. M., Moreno-Carretero, M. N., Quiros-Olozabal, M. & Ramirez-Exposito, M. J. (2008). J. Inorg. Biochem. 102, 1677–1683. Web of Science CSD CrossRef PubMed CAS Google Scholar
Khaledi, H., Saharin, S. M., Mohd Ali, H., Robinson, W. T. & Abdulla, M. A. (2009). Acta Cryst. E65, o1920. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, S.-Y. & You, Z. (2010a). Acta Cryst. E66, o1652. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, S.-Y. & You, Z. (2010b). Acta Cryst. E66, o1658. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, S.-Y. & You, Z. (2010c). Acta Cryst. E66, o1662. Web of Science CSD CrossRef IUCr Journals Google Scholar
Raj, K. K. V., Narayana, B., Ashalatha, B. V., Kumari, N. S. & Sarojini, B. K. (2007). Eur. J. Med. Chem. 42, 425–429. PubMed CAS Google Scholar
Shafiq, Z., Yaqub, M., Tahir, M. N., Hussain, A. & Iqbal, M. S. (2009). Acta Cryst. E65, o2898. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Vijayakumar, S., Adhikari, A., Kalluraya, B. & Chandrasekharan, K. (2009). Opt. Mater. 31, 1564–1569. Web of Science CrossRef CAS Google Scholar
Warad, I., Al-Nuri, M., Al-Resayes, S., Al-Farhan, K. & Ghazzali, M. (2009). Acta Cryst. E65, o1597. Web of Science CSD CrossRef IUCr Journals Google Scholar
Xu, L., Huang, S.-S., Zhang, B.-J., Wang, S.-Y. & Zhang, H.-L. (2009). Acta Cryst. E65, o2412. Web of Science CSD CrossRef IUCr Journals Google Scholar
Zhong, X., Wei, H.-L., Liu, W.-S., Wang, D.-Q. & Wang, X. (2007). Bioorg. Med. Chem. Lett. 17, 3774–3777. Web of Science CSD CrossRef PubMed CAS Google Scholar
Zhu, Q.-Y., Wei, Y.-J. & Wang, F.-W. (2009). Pol. J. Chem. 83, 1233–1240. CAS Google Scholar