Cyclo­oxygenase-1-selective inhibitor SC-560

Long, S.; Theiss, K.L.; Li, T.; Loftin, C.D.

doi:10.1107/S1600536809001779

organic compounds

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ISSN: 2056-9890

Volume 65| Part 2| February 2009| Page o360

doi:10.1107/S1600536809001779

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Cyclooxygenase-1-selective inhibitor SC-560

Sihui Long,^a Kathryn L. Theiss,^a Tonglei Li ^a and Charles D. Loftin ^a ^*

^aDepartment of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
^*Correspondence e-mail: cdloft2@uky.edu

(Received 11 December 2008; accepted 14 January 2009; online 23 January 2009)

In the title compound, 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole (SC-560), C₁₇H₁₂ClF₃N₂O, a COX-1-selective inhibitor, the dihedral angles between the heterocycle and the chlorobenzene and methoxybenzene rings are 41.66 (6) and 43.08 (7)°, respectively. The dihedral angle between the two phenyl rings is 59.94 (6)°. No classic hydrogen bonds are possible in the crystal, and intermolecular interactions must be mainly of the dispersion type. This information may aid the identification of dosage formulations with improved oral bioavailability.

Related literature

For background literature, see: Choi et al. (2008 ); Cusimano et al. (2007 ); Kundu & Fulton (2002 ); Penning et al. (1997 ); Smith et al. (2000 ); Teng et al. (2003 ); Tiano et al. (2002 ); For related structures, see: Allen (2002 ); Charlier et al. (2004 ); Norris et al. (2005 ); Sonar et al. (2004 ); Zhu et al. (2004 ).

Experimental

Crystal data

C₁₇H₁₂ClF₃N₂O
M_r = 352.74
Monoclinic, P 2₁ /n
a = 15.585 (3) Å
b = 7.1671 (14) Å
c = 15.789 (3) Å
β = 116.81 (3)°
V = 1574.1 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.28 mm⁻¹
T = 90 (2) K
0.20 × 0.10 × 0.10 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997 ) T_min = 0.946, T_max = 0.972
6895 measured reflections
3608 independent reflections
3030 reflections with I > 2σ(I)
R_int = 0.020

Refinement

R[F² > 2σ(F²)] = 0.035
wR(F²) = 0.094
S = 1.04
3608 reflections
218 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: COLLECT (Hooft, 1998 ); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; 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 and local procedures.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809001779/pv2130sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809001779/pv2130Isup2.hkl

checkCIF report

Comment top

Inhibition of the two cyclooxygenase (COX) isoforms is considered the primary mechanism responsible for both the therapeutic and toxic effects of nonsteroidal anti-inflammatory drugs (NSAIDS) (Smith, et al., 2000). Both of the COX isoforms have been shown to contribute to inflammation and tumor genesis, and therapeutic benefits may result from either COX-1 or COX-2 selective inhibition (Tiano, et al. 2002; Choi, et al. 2008; Kundu & Fulton, 2002; Cusimano, et al. 2007). The development of the COX-2-selective inhibitor celecoxib led to identification of a variety of structurally related compounds with varying selectivity for the COX isoforms, SC-560 was one of them (Penning, et al. 1997; Choi, et al. 2008). However, SC-560's poor bioavailability may limit its effects (Teng, et al. 2003). The information from crystal structure may provide direction in suitable dosage formulation. Herein, we describe the first crystal structure of SC-560, (I), a selective and potent inhibitor of the cyclooxygenase-1 isoform (Penning, et al. 1997).

The crystal structure of (I) is presented in Fig. 1. The structure lacks the moieties necessary for hydrogen-bonding to occur between molecules (Fig. 2). Thus, the lattice energy mainly consists of dispersion energies, which typically result in a low melting point because of the weak intermolecular interactions (as confirmed by melting point measurement). Despite the entire chemical structure being fused together by three aromatic rings, a large conjugate system between the rings is not seen due to steric repulsion between the two phenyl rings. Similar structures are abundant in the Cambridge Structural Database (CSD - Version 5.29; Allen, 2002), EYISAG (Sonar, et al. 2004), IZAYUD (Charlier, et al. 2004), JAQBIN (Norris, et al. 2005), and MAJGUA (Zhu, et al. 2004) are few of them. To conclude, the single-crystal structure of SC-560 was solved. Because there is no hydrogen bonding in the structure, the major contribution for the lattice energy stems from weak dispersion energies leading to its low melting point at 335.5 K.

Related literature top

For background literature, see: Choi et al. (2008); Cusimano et al. (2007); Kundu & Fulton (2002); Penning et al. (1997); Smith et al. (2000); Teng et al. (2003); Tiano et al. (2002); For related structures, see: Allen (2002); Charlier et al. (2004); Norris et al. (2005); Sonar et al. (2004); Zhu et al. (2004).

Experimental top

Commercial SC-560 was dissolved in HPLC grade methanol in a glass vial at room temperature. The vial was sealed with Parafilm with numerous pin-size holes introduced to allow for evaporation of the solvent. Colorless block crystals were obtained following approximately one week of slow evaporation.

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); 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) and local procedures.

Figures top

	Fig. 1. The molecular structure of (I), showing atom displacement ellipsoids at the 50% probability level.
	Fig. 2. Crystal packing of SC-560.

5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole top

Crystal data top

C₁₇H₁₂ClF₃N₂O	F(000) = 720
M_r = 352.74	D_x = 1.488 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 15.585 (3) Å	Cell parameters from 3880 reflections
b = 7.1671 (14) Å	θ = 1.0–27.5°
c = 15.789 (3) Å	µ = 0.28 mm⁻¹
β = 116.81 (3)°	T = 90 K
V = 1574.1 (5) Å³	Block, colorless
Z = 4	0.20 × 0.10 × 0.10 mm

Data collection top

Nonius KappaCCD diffractometer	3608 independent reflections
Radiation source: fine-focus sealed tube	3030 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.020
Detector resolution: 18 pixels mm^-1	θ_max = 27.5°, θ_min = 1.5°
ω scans at fixed χ = 55°	h = −20→20
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	k = −9→9
T_min = 0.946, T_max = 0.972	l = −20→20
6895 measured reflections

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)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.094	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0421P)² + 0.7994P] where P = (F_o² + 2F_c²)/3
3608 reflections	(Δ/σ)_max = 0.004
218 parameters	Δρ_max = 0.34 e Å⁻³
0 restraints	Δρ_min = −0.29 e Å⁻³

Crystal data top

C₁₇H₁₂ClF₃N₂O	V = 1574.1 (5) Å³
M_r = 352.74	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 15.585 (3) Å	µ = 0.28 mm⁻¹
b = 7.1671 (14) Å	T = 90 K
c = 15.789 (3) Å	0.20 × 0.10 × 0.10 mm
β = 116.81 (3)°

Data collection top

Nonius KappaCCD diffractometer	3608 independent reflections
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	3030 reflections with I > 2σ(I)
T_min = 0.946, T_max = 0.972	R_int = 0.020
6895 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.035	0 restraints
wR(F²) = 0.094	H-atom parameters constrained
S = 1.04	Δρ_max = 0.34 e Å⁻³
3608 reflections	Δρ_min = −0.29 e Å⁻³
218 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
Cl13	0.06492 (3)	0.90044 (6)	0.10611 (2)	0.02831 (12)
N2	0.38203 (8)	0.87316 (17)	0.67980 (8)	0.0188 (2)
O20	0.12419 (8)	0.14611 (15)	0.54981 (7)	0.0287 (3)
F3	0.56584 (7)	1.19886 (15)	0.74065 (7)	0.0382 (3)
F2	0.52162 (8)	1.04490 (15)	0.83041 (6)	0.0443 (3)
N1	0.32413 (8)	0.81035 (16)	0.59070 (7)	0.0169 (2)
C10	0.14398 (10)	0.89725 (19)	0.22720 (9)	0.0199 (3)
C5	0.33171 (9)	0.91657 (19)	0.52240 (9)	0.0171 (3)
C18	0.21726 (10)	0.3440 (2)	0.50702 (9)	0.0196 (3)
H18	0.2135	0.2529	0.4618	0.023*
F1	0.44389 (7)	1.28688 (15)	0.75784 (7)	0.0448 (3)
C11	0.10734 (10)	0.8619 (2)	0.29082 (10)	0.0199 (3)
H11	0.0408	0.8367	0.2688	0.024*
C19	0.26912 (9)	0.50583 (19)	0.51716 (9)	0.0179 (3)
H19	0.3033	0.5239	0.4809	0.021*
C7	0.26748 (10)	0.89925 (18)	0.41982 (9)	0.0170 (3)
C14	0.27105 (9)	0.64202 (19)	0.58060 (9)	0.0173 (3)
C16	0.17333 (11)	0.4491 (2)	0.62713 (10)	0.0244 (3)
H16	0.1419	0.4285	0.6657	0.029*
C6	0.48912 (10)	1.1368 (2)	0.74825 (10)	0.0222 (3)
C12	0.16930 (10)	0.86393 (19)	0.38715 (9)	0.0190 (3)
H12	0.1449	0.8411	0.4315	0.023*
C4	0.39888 (9)	1.0532 (2)	0.56958 (9)	0.0189 (3)
H4	0.4216	1.1482	0.5428	0.023*
C8	0.30233 (10)	0.9337 (2)	0.35415 (10)	0.0211 (3)
H8	0.3689	0.9576	0.3757	0.025*
C3	0.42585 (9)	1.0204 (2)	0.66545 (9)	0.0190 (3)
C15	0.22267 (10)	0.6153 (2)	0.63461 (10)	0.0222 (3)
H15	0.2231	0.7102	0.6768	0.027*
C17	0.17048 (10)	0.3143 (2)	0.56306 (10)	0.0217 (3)
C9	0.24066 (11)	0.9335 (2)	0.25715 (10)	0.0238 (3)
H9	0.2645	0.9578	0.2124	0.029*
C21	0.07544 (14)	0.1110 (3)	0.60633 (11)	0.0403 (5)
H21A	0.1214	0.1185	0.6737	0.060*
H21B	0.0468	−0.0138	0.5921	0.060*
H21C	0.0248	0.2043	0.5919	0.060*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl13	0.0288 (2)	0.0370 (2)	0.01330 (17)	0.00223 (16)	0.00434 (14)	0.00022 (14)
N2	0.0178 (6)	0.0216 (6)	0.0138 (5)	−0.0009 (5)	0.0044 (4)	−0.0028 (4)
O20	0.0349 (6)	0.0259 (6)	0.0258 (5)	−0.0125 (5)	0.0143 (5)	−0.0024 (4)
F3	0.0326 (5)	0.0472 (6)	0.0402 (5)	−0.0209 (5)	0.0211 (4)	−0.0206 (5)
F2	0.0533 (6)	0.0441 (6)	0.0177 (4)	−0.0183 (5)	0.0001 (4)	−0.0012 (4)
N1	0.0180 (5)	0.0186 (6)	0.0126 (5)	−0.0015 (5)	0.0057 (4)	−0.0014 (4)
C10	0.0238 (7)	0.0184 (7)	0.0134 (6)	0.0030 (5)	0.0046 (5)	0.0000 (5)
C5	0.0177 (6)	0.0180 (7)	0.0159 (6)	0.0022 (5)	0.0080 (5)	0.0011 (5)
C18	0.0207 (7)	0.0180 (7)	0.0178 (6)	0.0029 (5)	0.0067 (5)	−0.0008 (5)
F1	0.0342 (5)	0.0427 (6)	0.0472 (6)	0.0054 (5)	0.0092 (5)	−0.0268 (5)
C11	0.0187 (6)	0.0189 (7)	0.0189 (6)	0.0009 (5)	0.0059 (5)	0.0001 (5)
C19	0.0188 (6)	0.0189 (7)	0.0170 (6)	0.0031 (5)	0.0089 (5)	0.0019 (5)
C7	0.0200 (6)	0.0141 (6)	0.0150 (6)	0.0016 (5)	0.0063 (5)	0.0008 (5)
C14	0.0171 (6)	0.0177 (7)	0.0142 (6)	−0.0010 (5)	0.0045 (5)	0.0013 (5)
C16	0.0259 (7)	0.0312 (8)	0.0191 (6)	−0.0075 (6)	0.0127 (6)	−0.0023 (6)
C6	0.0208 (7)	0.0240 (8)	0.0207 (7)	−0.0022 (6)	0.0084 (6)	−0.0033 (6)
C12	0.0215 (7)	0.0192 (7)	0.0171 (6)	0.0008 (5)	0.0093 (5)	0.0011 (5)
C4	0.0182 (6)	0.0186 (7)	0.0189 (6)	0.0001 (5)	0.0073 (5)	0.0009 (5)
C8	0.0199 (7)	0.0237 (7)	0.0193 (7)	−0.0004 (6)	0.0084 (5)	0.0003 (5)
C3	0.0166 (6)	0.0195 (7)	0.0191 (6)	0.0013 (5)	0.0066 (5)	−0.0008 (5)
C15	0.0238 (7)	0.0262 (8)	0.0172 (6)	−0.0032 (6)	0.0097 (6)	−0.0044 (6)
C17	0.0204 (7)	0.0213 (7)	0.0188 (6)	−0.0037 (6)	0.0048 (5)	0.0024 (5)
C9	0.0270 (7)	0.0280 (8)	0.0177 (6)	0.0000 (6)	0.0113 (6)	0.0009 (6)
C21	0.0495 (11)	0.0482 (11)	0.0253 (8)	−0.0297 (9)	0.0188 (8)	−0.0057 (7)

Geometric parameters (Å, º) top

Cl13—C10	1.7461 (15)	C19—C14	1.3892 (19)
N2—C3	1.3307 (18)	C19—H19	0.9500
N2—N1	1.3605 (15)	C7—C8	1.3924 (19)
O20—C17	1.3714 (18)	C7—C12	1.3998 (19)
O20—C21	1.4312 (19)	C14—C15	1.383 (2)
F3—C6	1.3308 (17)	C16—C17	1.385 (2)
F2—C6	1.3345 (17)	C16—C15	1.393 (2)
N1—C5	1.3680 (17)	C16—H16	0.9500
N1—C14	1.4305 (17)	C6—C3	1.4884 (19)
C10—C11	1.384 (2)	C12—H12	0.9500
C10—C9	1.385 (2)	C4—C3	1.3962 (19)
C5—C4	1.3807 (19)	C4—H4	0.9500
C5—C7	1.4759 (18)	C8—C9	1.394 (2)
C18—C19	1.381 (2)	C8—H8	0.9500
C18—C17	1.393 (2)	C15—H15	0.9500
C18—H18	0.9500	C9—H9	0.9500
F1—C6	1.3313 (18)	C21—H21A	0.9800
C11—C12	1.3861 (19)	C21—H21B	0.9800
C11—H11	0.9500	C21—H21C	0.9800

C3—N2—N1	103.79 (11)	F1—C6—F2	106.06 (12)
C17—O20—C21	116.75 (12)	F3—C6—C3	111.98 (12)
N2—N1—C5	112.22 (11)	F1—C6—C3	112.21 (12)
N2—N1—C14	118.35 (11)	F2—C6—C3	112.80 (13)
C5—N1—C14	129.25 (11)	C11—C12—C7	120.73 (13)
C11—C10—C9	121.85 (13)	C11—C12—H12	119.6
C11—C10—Cl13	118.59 (11)	C7—C12—H12	119.6
C9—C10—Cl13	119.55 (11)	C5—C4—C3	104.46 (12)
N1—C5—C4	106.47 (11)	C5—C4—H4	127.8
N1—C5—C7	124.14 (12)	C3—C4—H4	127.8
C4—C5—C7	128.73 (12)	C7—C8—C9	120.73 (13)
C19—C18—C17	120.10 (13)	C7—C8—H8	119.6
C19—C18—H18	120.0	C9—C8—H8	119.6
C17—C18—H18	120.0	N2—C3—C4	113.05 (12)
C10—C11—C12	118.89 (13)	N2—C3—C6	118.86 (12)
C10—C11—H11	120.6	C4—C3—C6	127.88 (13)
C12—C11—H11	120.6	C14—C15—C16	119.99 (13)
C18—C19—C14	119.66 (12)	C14—C15—H15	120.0
C18—C19—H19	120.2	C16—C15—H15	120.0
C14—C19—H19	120.2	O20—C17—C16	124.47 (13)
C8—C7—C12	119.10 (12)	O20—C17—C18	115.32 (13)
C8—C7—C5	120.19 (12)	C16—C17—C18	120.21 (13)
C12—C7—C5	120.48 (12)	C10—C9—C8	118.70 (13)
C15—C14—C19	120.45 (13)	C10—C9—H9	120.6
C15—C14—N1	119.79 (12)	C8—C9—H9	120.6
C19—C14—N1	119.76 (12)	O20—C21—H21A	109.5
C17—C16—C15	119.53 (13)	O20—C21—H21B	109.5
C17—C16—H16	120.2	H21A—C21—H21B	109.5
C15—C16—H16	120.2	O20—C21—H21C	109.5
F3—C6—F1	106.49 (12)	H21A—C21—H21C	109.5
F3—C6—F2	106.86 (12)	H21B—C21—H21C	109.5

C3—N2—N1—C5	−0.10 (14)	C12—C7—C8—C9	0.1 (2)
C3—N2—N1—C14	175.45 (11)	C5—C7—C8—C9	−174.46 (13)
N2—N1—C5—C4	0.92 (15)	N1—N2—C3—C4	−0.79 (15)
C14—N1—C5—C4	−174.02 (12)	N1—N2—C3—C6	174.38 (12)
N2—N1—C5—C7	−170.48 (12)	C5—C4—C3—N2	1.34 (16)
C14—N1—C5—C7	14.6 (2)	C5—C4—C3—C6	−173.29 (13)
C9—C10—C11—C12	0.3 (2)	F3—C6—C3—N2	143.23 (13)
Cl13—C10—C11—C12	−178.35 (11)	F1—C6—C3—N2	−97.07 (16)
C17—C18—C19—C14	−2.7 (2)	F2—C6—C3—N2	22.64 (18)
N1—C5—C7—C8	−147.72 (14)	F3—C6—C3—C4	−42.4 (2)
C4—C5—C7—C8	42.9 (2)	F1—C6—C3—C4	77.29 (18)
N1—C5—C7—C12	37.8 (2)	F2—C6—C3—C4	−163.00 (14)
C4—C5—C7—C12	−131.61 (15)	C19—C14—C15—C16	1.4 (2)
C18—C19—C14—C15	1.0 (2)	N1—C14—C15—C16	−178.04 (12)
C18—C19—C14—N1	−179.52 (12)	C17—C16—C15—C14	−2.2 (2)
N2—N1—C14—C15	45.45 (17)	C21—O20—C17—C16	0.4 (2)
C5—N1—C14—C15	−139.87 (14)	C21—O20—C17—C18	179.96 (14)
N2—N1—C14—C19	−134.02 (13)	C15—C16—C17—O20	180.00 (13)
C5—N1—C14—C19	40.7 (2)	C15—C16—C17—C18	0.5 (2)
C10—C11—C12—C7	−0.6 (2)	C19—C18—C17—O20	−177.60 (12)
C8—C7—C12—C11	0.4 (2)	C19—C18—C17—C16	2.0 (2)
C5—C7—C12—C11	174.95 (13)	C11—C10—C9—C8	0.2 (2)
N1—C5—C4—C3	−1.30 (15)	Cl13—C10—C9—C8	178.84 (11)
C7—C5—C4—C3	169.57 (13)	C7—C8—C9—C10	−0.4 (2)

Experimental details

Crystal data
Chemical formula	C₁₇H₁₂ClF₃N₂O
M_r	352.74
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	90
a, b, c (Å)	15.585 (3), 7.1671 (14), 15.789 (3)
β (°)	116.81 (3)
V (Å³)	1574.1 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.28
Crystal size (mm)	0.20 × 0.10 × 0.10

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	Multi-scan (SCALEPACK; Otwinowski & Minor, 1997)
T_min, T_max	0.946, 0.972
No. of measured, independent and observed [I > 2σ(I)] reflections	6895, 3608, 3030
R_int	0.020
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.035, 0.094, 1.04
No. of reflections	3608
No. of parameters	218
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.34, −0.29

Computer programs: COLLECT (Hooft, 1998), DENZO-SMN (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and local procedures.

Acknowledgements

SL and TL are grateful for financial support by the NSF (DMR– 0449633). The authors also thank Dr Sean Parkin for providing laboratory facilities and for helpful discussions.

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