5-Methyl-2-phenyl-2H-pyrazol-3-ol

Wang, Q.; Zhang, Y.; Wang, R.; Yang, Y.-L.; Zhi, F.

doi:10.1107/S1600536808028559

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 64| Part 10| October 2008| Page o1924

doi:10.1107/S1600536808028559

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5-Methyl-2-phenyl-2H-pyrazol-3-ol

Qiang Wang,^a Yi Zhang,^a Rong Wang,^a Yi-Lin Yang ^a ^* and Feng Zhi ^b ^*

^aDepartment of Neurosurgery, Third Affiliated Hospital of Soochow University, Changzhou 213003, People's Republic of China, and ^bLaboratory of Neuronal Injury and Protection, Third Affiliated Hospital of Soochow University, Changzhou 213003, People's Republic of China
^*Correspondence e-mail: czfph@yahoo.com.cn, danielzhif@yahoo.com.cn

(Received 28 August 2008; accepted 6 September 2008; online 13 September 2008)

The title compound, C₁₀H₁₀N₂O, known as Edaravone (MCI-186), was crystallized from methanol. The two independent molecules in the asymmetric unit are linked through an O—H⋯O hydrogen bond. One molecule adopts a ketone form, while the other adopts an enol form. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains running along the b axis.

Related literature

For background to the compound, see: Watanabe et al. (1994 ); The Edaravone Acute Infarction Study Group (2003 ). For bond-length data, see: Allen et al. (1987 ).

Experimental

Crystal data

C₁₀H₁₀N₂O
M_r = 174.20
Monoclinic, P 2₁ /c
a = 10.336 (2) Å
b = 11.154 (2) Å
c = 15.863 (3) Å
β = 95.157 (3)°
V = 1821.4 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 (2) K
0.23 × 0.23 × 0.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.981, T_max = 0.983
10551 measured reflections
3923 independent reflections
2894 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.040
wR(F²) = 0.106
S = 1.04
3923 reflections
243 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯N4ⁱ	0.907 (9)	1.904 (10)	2.7999 (17)	169.4 (17)
O2—H2B⋯O1	0.870 (9)	1.618 (10)	2.4813 (15)	170.9 (19)
Symmetry code: (i) x, y-1, z.

Data collection: SMART (Bruker, 2002 ); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808028559/sg2259sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808028559/sg2259Isup2.hkl

checkCIF report

Comment top

Edaravone (5-methyl-2-phenyl-2H-pyrazol-3-ol, MCI-186) is a free-radical scavenger that was approved by the Ministry of Health, Labor, and Welfare of Japan in 2001, and is now widely used for the treatment of acute cerebral infarction (Watanabe et al.., 1994; The Edaravone Acute Infarction Study Group, 2003). We report in this paper the crystal structure of the compound, (I).

The compound consists of two independent molecules (Fig. 1), which are linked through an intramolecular O2—H2B···O1 hydrogen bond (Table 1). One molecule adopts a ketone form, while the other adopts an enol form. In the ketone molecule, the dihedral angle between the C1–C6 benzene ring and the N1/N2/C9/C8/C7 ring is 22.9 (2)°. In the enol molecule, the dihedral angle between the C11–C16 benzene ring and the N3/N4/C19/C18/C17 ring is 34.3 (2)°. In the compound, all the bond lengths are within normal ranges (Allen et al., 1987). The bond length of C17—O2 [1.325 (2) Å] is longer than that of C7—O1 [1.260 (2) Å], which is caused by the enol form.

In the crystal structure, molecules are linked through intermolecular N–H···O hydrogen bonds (Table 1), forming chains running along the b axis (Fig. 2).

Related literature top

For the background of the compound, see: Watanabe et al. (1994); The Edaravone Acute Infarction Study Group (2003). For bond-length data, see: Allen et al. (1987).

Experimental top

The crystal of the compound was recrystallized by edaravone in methanol.

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); 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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The structure of (I) at the 30% probability level. Intramolecular hydrogen bonds are shown as dashed lines.
	Fig. 2. Molecular packing of (I), viewed along the a axis. Intermolecular hydrogen bonds are shown as dashed lines.

5-Methyl-2-phenyl-2H-pyrazol-3-ol top

Crystal data top

C₁₀H₁₀N₂O	F(000) = 736
M_r = 174.20	D_x = 1.271 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3931 reflections
a = 10.336 (2) Å	θ = 2.3–29.0°
b = 11.154 (2) Å	µ = 0.09 mm⁻¹
c = 15.863 (3) Å	T = 298 K
β = 95.157 (3)°	Block, colorless
V = 1821.4 (6) Å³	0.23 × 0.23 × 0.20 mm
Z = 8

Data collection top

Bruker SMART CCD area-detector diffractometer	3923 independent reflections
Radiation source: fine-focus sealed tube	2894 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ω scan	θ_max = 27.0°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −13→11
T_min = 0.981, T_max = 0.983	k = −13→14
10551 measured reflections	l = −20→18

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.040	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.106	w = 1/[σ²(F_o²) + (0.0428P)² + 0.3053P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
3923 reflections	Δρ_max = 0.17 e Å⁻³
243 parameters	Δρ_min = −0.14 e Å⁻³
2 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0087 (12)

Crystal data top

C₁₀H₁₀N₂O	V = 1821.4 (6) Å³
M_r = 174.20	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.336 (2) Å	µ = 0.09 mm⁻¹
b = 11.154 (2) Å	T = 298 K
c = 15.863 (3) Å	0.23 × 0.23 × 0.20 mm
β = 95.157 (3)°

Data collection top

Bruker SMART CCD area-detector diffractometer	3923 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2894 reflections with I > 2σ(I)
T_min = 0.981, T_max = 0.983	R_int = 0.025
10551 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.040	2 restraints
wR(F²) = 0.106	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.17 e Å⁻³
3923 reflections	Δρ_min = −0.14 e Å⁻³
243 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	0.76081 (11)	0.23408 (9)	0.09473 (8)	0.0652 (3)
O2	0.63865 (11)	0.42520 (9)	0.07652 (7)	0.0577 (3)
N1	0.80235 (11)	0.03414 (9)	0.07061 (8)	0.0469 (3)
N2	0.76341 (13)	−0.04917 (10)	0.00921 (8)	0.0516 (3)
N3	0.69321 (11)	0.62596 (9)	0.06745 (7)	0.0418 (3)
N4	0.76998 (12)	0.70070 (10)	0.02382 (8)	0.0490 (3)
C1	0.91015 (13)	0.01075 (12)	0.12978 (9)	0.0457 (3)
C2	0.92942 (16)	0.07840 (15)	0.20276 (10)	0.0603 (4)
H2	0.8722	0.1399	0.2131	0.072*
C3	1.03427 (19)	0.05375 (19)	0.26009 (12)	0.0768 (5)
H3	1.0481	0.0997	0.3090	0.092*
C4	1.1181 (2)	−0.0372 (2)	0.24600 (13)	0.0814 (6)
H4	1.1881	−0.0536	0.2853	0.098*
C5	1.09872 (17)	−0.10395 (18)	0.17403 (14)	0.0755 (5)
H5	1.1557	−0.1661	0.1647	0.091*
C6	0.99550 (15)	−0.08041 (15)	0.11475 (11)	0.0597 (4)
H6	0.9837	−0.1255	0.0653	0.072*
C7	0.73814 (14)	0.14046 (12)	0.05144 (10)	0.0486 (4)
C8	0.65398 (16)	0.11675 (14)	−0.02083 (10)	0.0566 (4)
H8	0.5970	0.1713	−0.0486	0.068*
C9	0.66976 (15)	0.00076 (14)	−0.04331 (10)	0.0536 (4)
C10	0.6047 (2)	−0.07170 (17)	−0.11335 (11)	0.0760 (5)
H10A	0.6586	−0.0744	−0.1596	0.114*
H10B	0.5227	−0.0359	−0.1321	0.114*
H10C	0.5908	−0.1517	−0.0937	0.114*
C11	0.61818 (14)	0.67394 (12)	0.12999 (8)	0.0441 (3)
C12	0.49765 (15)	0.62664 (14)	0.14196 (10)	0.0545 (4)
H12	0.4655	0.5611	0.1104	0.065*
C13	0.42556 (18)	0.67832 (19)	0.20167 (12)	0.0755 (6)
H13	0.3450	0.6462	0.2108	0.091*
C14	0.4708 (2)	0.7760 (2)	0.24752 (12)	0.0860 (7)
H14	0.4205	0.8110	0.2866	0.103*
C15	0.5904 (2)	0.82150 (17)	0.23553 (11)	0.0799 (6)
H15	0.6213	0.8876	0.2669	0.096*
C16	0.66614 (18)	0.77067 (13)	0.17737 (10)	0.0584 (4)
H16	0.7482	0.8012	0.1703	0.070*
C17	0.70530 (13)	0.51085 (11)	0.04194 (9)	0.0430 (3)
C18	0.79096 (15)	0.51055 (13)	−0.01882 (10)	0.0526 (4)
H18	0.8190	0.4445	−0.0479	0.063*
C19	0.82756 (15)	0.62954 (13)	−0.02813 (10)	0.0510 (4)
C20	0.91583 (19)	0.68181 (17)	−0.08846 (13)	0.0794 (6)
H20A	0.9060	0.7674	−0.0900	0.119*
H20B	0.8938	0.6496	−0.1440	0.119*
H20C	1.0042	0.6619	−0.0700	0.119*
H2A	0.7692 (17)	−0.1287 (9)	0.0208 (11)	0.080*
H2B	0.6823 (16)	0.3585 (12)	0.0773 (12)	0.080*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0757 (7)	0.0322 (5)	0.0864 (8)	0.0043 (5)	−0.0001 (6)	−0.0043 (5)
O2	0.0673 (7)	0.0311 (5)	0.0772 (7)	0.0007 (5)	0.0205 (6)	0.0059 (5)
N1	0.0531 (7)	0.0283 (6)	0.0577 (7)	0.0011 (5)	−0.0031 (6)	0.0011 (5)
N2	0.0640 (8)	0.0310 (6)	0.0581 (7)	0.0018 (5)	−0.0030 (6)	0.0012 (5)
N3	0.0493 (6)	0.0298 (6)	0.0476 (6)	0.0024 (5)	0.0114 (5)	0.0017 (5)
N4	0.0588 (8)	0.0324 (6)	0.0582 (7)	−0.0021 (5)	0.0185 (6)	0.0015 (5)
C1	0.0456 (8)	0.0362 (7)	0.0551 (8)	−0.0040 (6)	0.0031 (6)	0.0098 (6)
C2	0.0646 (10)	0.0555 (10)	0.0603 (10)	−0.0023 (8)	0.0035 (8)	0.0003 (8)
C3	0.0793 (13)	0.0876 (14)	0.0607 (11)	−0.0113 (11)	−0.0084 (9)	0.0024 (10)
C4	0.0653 (12)	0.1020 (16)	0.0736 (12)	−0.0004 (11)	−0.0122 (10)	0.0206 (12)
C5	0.0569 (10)	0.0769 (12)	0.0919 (14)	0.0161 (9)	0.0016 (10)	0.0187 (11)
C6	0.0567 (9)	0.0531 (9)	0.0687 (10)	0.0082 (7)	0.0024 (8)	0.0050 (8)
C7	0.0513 (8)	0.0310 (7)	0.0640 (9)	0.0023 (6)	0.0082 (7)	0.0075 (7)
C8	0.0597 (9)	0.0453 (9)	0.0635 (10)	0.0101 (7)	−0.0019 (8)	0.0127 (7)
C9	0.0599 (9)	0.0477 (9)	0.0523 (8)	0.0013 (7)	−0.0006 (7)	0.0069 (7)
C10	0.0886 (13)	0.0739 (12)	0.0622 (10)	−0.0045 (10)	−0.0120 (9)	−0.0032 (9)
C11	0.0544 (8)	0.0339 (7)	0.0447 (7)	0.0122 (6)	0.0093 (6)	0.0067 (6)
C12	0.0524 (9)	0.0531 (9)	0.0586 (9)	0.0130 (7)	0.0090 (7)	0.0135 (7)
C13	0.0686 (11)	0.0872 (14)	0.0749 (12)	0.0326 (10)	0.0304 (9)	0.0286 (11)
C14	0.1171 (18)	0.0853 (15)	0.0612 (11)	0.0533 (13)	0.0383 (12)	0.0143 (11)
C15	0.1298 (18)	0.0540 (11)	0.0579 (10)	0.0258 (11)	0.0198 (11)	−0.0063 (8)
C16	0.0812 (11)	0.0414 (8)	0.0537 (9)	0.0066 (8)	0.0121 (8)	−0.0019 (7)
C17	0.0495 (8)	0.0285 (6)	0.0511 (7)	0.0027 (6)	0.0048 (6)	0.0015 (6)
C18	0.0622 (9)	0.0379 (8)	0.0597 (9)	0.0065 (7)	0.0166 (7)	−0.0068 (7)
C19	0.0538 (8)	0.0432 (8)	0.0580 (9)	0.0022 (6)	0.0163 (7)	−0.0002 (7)
C20	0.0868 (13)	0.0683 (12)	0.0901 (13)	−0.0032 (10)	0.0467 (11)	0.0008 (10)

Geometric parameters (Å, º) top

O1—C7	1.260 (2)	C8—C9	1.356 (2)
O2—C17	1.325 (2)	C8—H8	0.9300
O2—H2B	0.870 (9)	C9—C10	1.485 (2)
N1—C7	1.379 (2)	C10—H10A	0.9600
N1—N2	1.380 (2)	C10—H10B	0.9600
N1—C1	1.415 (2)	C10—H10C	0.9600
N2—C9	1.340 (2)	C11—C16	1.381 (2)
N2—H2A	0.907 (9)	C11—C12	1.382 (2)
N3—C17	1.355 (2)	C12—C13	1.383 (2)
N3—N4	1.379 (2)	C12—H12	0.9300
N3—C11	1.418 (2)	C13—C14	1.369 (3)
N4—C19	1.323 (2)	C13—H13	0.9300
C1—C6	1.381 (2)	C14—C15	1.365 (3)
C1—C2	1.381 (2)	C14—H14	0.9300
C2—C3	1.378 (2)	C15—C16	1.384 (2)
C2—H2	0.9300	C15—H15	0.9300
C3—C4	1.366 (3)	C16—H16	0.9300
C3—H3	0.9300	C17—C18	1.366 (2)
C4—C5	1.362 (3)	C18—C19	1.392 (2)
C4—H4	0.9300	C18—H18	0.9300
C5—C6	1.383 (2)	C19—C20	1.498 (2)
C5—H5	0.9300	C20—H20A	0.9600
C6—H6	0.9300	C20—H20B	0.9600
C7—C8	1.400 (2)	C20—H20C	0.9600

C17—O2—H2B	109.5 (13)	C9—C10—H10B	109.5
C7—N1—N2	108.62 (11)	H10A—C10—H10B	109.5
C7—N1—C1	129.74 (12)	C9—C10—H10C	109.5
N2—N1—C1	120.42 (11)	H10A—C10—H10C	109.5
C9—N2—N1	107.91 (11)	H10B—C10—H10C	109.5
C9—N2—H2A	124.3 (11)	C16—C11—C12	120.50 (14)
N1—N2—H2A	120.4 (12)	C16—C11—N3	118.91 (13)
C17—N3—N4	110.49 (11)	C12—C11—N3	120.57 (13)
C17—N3—C11	129.60 (11)	C11—C12—C13	118.88 (17)
N4—N3—C11	119.90 (10)	C11—C12—H12	120.6
C19—N4—N3	105.14 (11)	C13—C12—H12	120.6
C6—C1—C2	120.05 (14)	C14—C13—C12	121.09 (19)
C6—C1—N1	119.90 (13)	C14—C13—H13	119.5
C2—C1—N1	120.05 (13)	C12—C13—H13	119.5
C3—C2—C1	119.32 (17)	C15—C14—C13	119.52 (17)
C3—C2—H2	120.3	C15—C14—H14	120.2
C1—C2—H2	120.3	C13—C14—H14	120.2
C4—C3—C2	120.86 (18)	C14—C15—C16	120.93 (19)
C4—C3—H3	119.6	C14—C15—H15	119.5
C2—C3—H3	119.6	C16—C15—H15	119.5
C5—C4—C3	119.69 (17)	C11—C16—C15	119.06 (18)
C5—C4—H4	120.2	C11—C16—H16	120.5
C3—C4—H4	120.2	C15—C16—H16	120.5
C4—C5—C6	120.84 (18)	O2—C17—N3	119.60 (12)
C4—C5—H5	119.6	O2—C17—C18	133.19 (13)
C6—C5—H5	119.6	N3—C17—C18	107.21 (12)
C1—C6—C5	119.23 (17)	C17—C18—C19	105.80 (12)
C1—C6—H6	120.4	C17—C18—H18	127.1
C5—C6—H6	120.4	C19—C18—H18	127.1
O1—C7—N1	122.01 (13)	N4—C19—C18	111.36 (13)
O1—C7—C8	132.37 (13)	N4—C19—C20	119.87 (13)
N1—C7—C8	105.62 (12)	C18—C19—C20	128.74 (14)
C9—C8—C7	108.35 (13)	C19—C20—H20A	109.5
C9—C8—H8	125.8	C19—C20—H20B	109.5
C7—C8—H8	125.8	H20A—C20—H20B	109.5
N2—C9—C8	109.29 (14)	C19—C20—H20C	109.5
N2—C9—C10	119.47 (14)	H20A—C20—H20C	109.5
C8—C9—C10	131.23 (15)	H20B—C20—H20C	109.5
C9—C10—H10A	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···N4ⁱ	0.91 (1)	1.90 (1)	2.7999 (17)	169 (2)
O2—H2B···O1	0.87 (1)	1.62 (1)	2.4813 (15)	171 (2)

Symmetry code: (i) x, y−1, z.

Experimental details

Crystal data
Chemical formula	C₁₀H₁₀N₂O
M_r	174.20
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	10.336 (2), 11.154 (2), 15.863 (3)
β (°)	95.157 (3)
V (Å³)	1821.4 (6)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.23 × 0.23 × 0.20

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.981, 0.983
No. of measured, independent and observed [I > 2σ(I)] reflections	10551, 3923, 2894
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.639

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.040, 0.106, 1.04
No. of reflections	3923
No. of parameters	243
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.14

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···N4ⁱ	0.907 (9)	1.904 (10)	2.7999 (17)	169.4 (17)
O2—H2B···O1	0.870 (9)	1.618 (10)	2.4813 (15)	170.9 (19)

Symmetry code: (i) x, y−1, z.

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
Bruker (2002). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
The Edaravone Acute Infarction Study Group (2003). Cerebrovasc. Dis. 15, 222–229. Web of Science CrossRef PubMed Google Scholar
Watanabe, T., Yuki, S., Egawa, M. & Nishi, H. (1994). J. Pharmacol. Exp. Ther. 268, 1597–1604. CAS PubMed Web of Science Google Scholar

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Volume 64| Part 10| October 2008| Page o1924

doi:10.1107/S1600536808028559

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