4-Hydr­oxy-3-meth­oxy-5-nitro­aceto­phenone (5-nitro­apocynin)

Babu, S.; Raghavamenon, A.C.; Fronczek, F.R.; Uppu, R.M.

doi:10.1107/S160053680903390X

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 9| September 2009| Pages o2292-o2293

doi:10.1107/S160053680903390X

Open

access

4-Hydroxy-3-methoxy-5-nitroacetophenone (5-nitroapocynin)

Sainath Babu,^a Achuthan C. Raghavamenon,^a Frank R. Fronczek ^b and Rao M. Uppu ^a ^*

^aDepartment of Environmental Toxicology and the Health Research Center, Southern University and A&M College, Baton Rouge, LA 70813, USA, and ^bDepartment of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804, USA
^*Correspondence e-mail: rao_uppu@subr.edu

(Received 20 August 2009; accepted 25 August 2009; online 29 August 2009)

The title molecule, C₉H₉NO₅, is close to planar (r.m.s. deviation from the mean plane of the non-H atoms = 0.058 Å). The OH group forms a bifurcated O—H⋯(O,O) hydrogen bond, with the intramolecular component to a nitro O atom and the intermolecular component to a keto O atom, the latter resulting in chains along [20 $[\overline{1}]$ ]. A C—H⋯O interaction reinforces the packing.

Related literature

For medicinal background, see: Gernapudi et al. (2009 ); Geronikaki & Gavalas (2006 ); Hayashi et al. (2005 ); Heumuller et al. (2008 ); Matés et al. (2009 ); Muijsers et al. (2001 ); Sawa et al. (2000 ); Schopfer et al. (2003 ); Stefanska & Pawliczak (2008 ); Stolk et al. (1994 ); Tajik et al. (2009 ); Thomas et al. (2002 ); Touyz (2008 ); Ximenes et al. (2007 ).

Experimental

Crystal data

C₉H₉NO₅
M_r = 211.17
Monoclinic, P 2₁ /c
a = 6.6598 (10) Å
b = 16.815 (2) Å
c = 8.0491 (11) Å
β = 96.485 (7)°
V = 895.6 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 90 K
0.40 × 0.30 × 0.15 mm

Data collection

Nonius KappaCCD diffractometer with Oxford Cryostream
Absorption correction: none
22479 measured reflections
4255 independent reflections
3226 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.042
wR(F²) = 0.120
S = 1.04
4255 reflections
147 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.62 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O⋯O4	0.878 (14)	1.850 (15)	2.5939 (10)	141.3 (13)
O1—H1O⋯O3ⁱ	0.878 (14)	2.271 (14)	2.8660 (9)	124.9 (12)
C2—H2⋯O4ⁱⁱ	0.952 (12)	2.439 (12)	3.3831 (12)	171.4 (11)
Symmetry codes: (i) $[x+1, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) $[x-1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: COLLECT (Nonius, 2000 ); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ); data reduction: DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680903390X/hb5058sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053680903390X/hb5058Isup2.hkl

checkCIF report

Comment top

The growing concern of multiple side effects associated with the use of steroidal anti-inflammatory drugs has led investigators to explore alternative and more natural remedies to counter oxidative stress in cancer and other degenerative diseases (Geronikaki & Gavalas, 2006; Matés et al., 2009). Apocynin (4-hydroxy-3-methoxy-acetophenone), also called acetovanillone, isolated from plants belonging to the apocyanaceae family (e.g., Apocynum cannabinum) seems to be a promising drug (or prodrug) that can be effective in various inflammatory conditions (Hayashi et al., 2005; Muijsers et al., 2001; Stefanska & Pawliczak, 2008). For a long time, apocynin has been thought to inhibit plasma membrane NADPH oxidase activity by interfering with the assembly of its cytosolic components, p40, p47, and p67 (Stolk et al., 1994). This view of a direct action of apocynin on the NADPH oxidase system has been challenged in recent years (Heumuller et al., 2008). Suggestions have been made that apocynin requires metabolic activation to diapocynin (DiApo), presumably involving intracellular peroxidase(s) (Touyz, 2008; Ximenes et al., 2007). In a recent study, we showed that apocynin readily reacts with free radicals of carbonate (CO₃^.-) and nitrogen dioxide (^.NO₂) formed in reactions of peroxynitrite (PN) with CO₂, resulting in the formation of 5-nitroapocynin and DiApo as major products (Gernapudi et al., 2009). Based on these observations, it has been suggested that a detailed study of the oxidative transformation of apocynin and its derivates by PN/CO₂ and possibly other oxidative, nitrative and/or nitrosative systems (Sawa et al., 2000; Schopfer et al., 2003; Thomas et al., 2002) would be necessary to provide a template for screening of antioxidant activity and a module that could help in the design of effective inhibitors of the NADPH oxidase system. Towards this end, we have synthesized 5-nitroapocynin using sodium nitrate in combination with an acidic ionic liquid, 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim] [HSO₄]), in CH₃CN solvent at room temperature (Fig. 3).

The molecule is shown in Fig. 1. The phenyl ring is essentially planar, with RMS deviation 0.0046 Å and maximum deviation 0.0069 (6) Å for C5. The substituents are twisted only slightly out of the phenyl plane, as described in the Abstract. Figure 2 shows the hydrogen bonding pattern, in which the OH group forms both an intramolecular interaction and a much less linear intermolecular interaction. These are described in Table 2, and form a chain in the [201] direction. The intermolecular component is accompanied by a near-linear C2–H2···O4 (at x - 1, 1/2 - y, 1/2 + z) interaction, having C···O distance 3.3831 (12) Å, H···O distance 2.439 (12) Å, and angle 171.4 (11)° about H. The N1–O4 bond, 1.2438 (10) Å, to the O atom involved in the intramolecular hydrogen bond, is slightly longer than the other, N1–O5, 1.2255 (10) Å.

Related literature top

For medicinal background, see: Gernapudi et al. (2009); Geronikaki & Gavalas (2006); Hayashi et al. (2005); Heumuller et al. (2008); Matés et al. (2009); Muijsers et al. (2001); Sawa et al. (2000); Schopfer et al. (2003); Stefanska & Pawliczak (2008); Stolk et al. (1994); Tajik et al. (2009); Thomas et al. (2002); Touyz (2008); Ximenes et al. (2007). AUTHOR: Fig. 1 is missing. Please supply labelled ellipsoid plot

Experimental top

Chemicals and solvents used in the synthesis and recrystallization were obtained as follows: apocynin, [bmim] [HSO₄], and sodium nitrate from Sigma (St. Louis, MO) and acetonitrile and hexane from Mallinckrodt (Phillipsburg, NJ). Water used was ultrapure with resistance ≥18.2 MΩ/cm.

Nitration of apocynin (Fig. 3) was performed according to the method of Tajik and colleagues (Tajik et al., 2009) with some modifications. Briefly, to 3.32 g (20 mmol) of apocynin in 80 ml of CH₃CN was added 5.72 g (20 mmol) of [bmim] [HSO₄] and 1.7 g (20 mmol) of NaNO₃, and the mixture was stirred at room temperature. Aliquots (0. 1 ml each) of the reaction mixture, drawn at various time points, were diluted 100–500-fold with 0.1 N NaOH and measured photometrically at 410 nm. When the absorbance at 410 nm reached a maximum (i.e., typically after 24 h), the reaction mixture was filtered and the filtrate evaporated under low pressure (200 mm H g) with mild heating (50°C or slightly higher). The thick brown liquid-like residue was extracted with hot hexane and recrystallized twice. The compound resolved as a single peak (retention time = 11.507 min) on Varian VF-5MS capillary column (30-m length, 0.25-mm internal diameter, 0.25-µm film thickness) with helium as the carrier gas at a flow of 1 ml. min^-1 (injection port, 250°C; oven, 60°C for 5 min (isothermal); 20°C min^-1 up to 230°C (ramp), and held at 230 °C for 18.5 min (isothermal); split, 25:1). The ion chromatogram of the peak eluting at 11.507 min showed a molecular ion [M]⁺ at m/z 211 (31%; relative to the base peak) and other fragments at m/z values of 196 (100%; base peak; [M—CH₃]⁺), 150 (23%; [M—CH₃NO₂]^+.), 122 (11%; [M—C₂H₃NO₃]^+.) and 79 (6%; [M—C₄H₆NO₄]^+.) (Fig. 4). Single crystals of (I) in the form of golden-yellow needles were grown from methanol.

Computing details top

Data collection: COLLECT (Nonius, 2000); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of (I): ellipsoids at the 50% level, with H atoms having arbitrary radius.
	Fig. 2. A portion of the hydrogen-bonded chain, showing the bifurcated hydrogen bond and accompanying C–H···O interaction; (ii) x - 1, 1/2 - y, 1/2 + z.
	Fig. 3. Nitration of apocynin
	Fig. 4. A proposed route of mass spectrometry-electron ionization (70 eV) fragmentation of 4-hydroxy-3-methoxy-5-nitroacetophenone.

4-Hydroxy-3-methoxy-5-nitroacetophenone top

Crystal data top

C₉H₉NO₅	F(000) = 440
M_r = 211.17	D_x = 1.566 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4183 reflections
a = 6.6598 (10) Å	θ = 2.5–36.3°
b = 16.815 (2) Å	µ = 0.13 mm⁻¹
c = 8.0491 (11) Å	T = 90 K
β = 96.485 (7)°	Needle fragment, golden yellow
V = 895.6 (2) Å³	0.40 × 0.30 × 0.15 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer with Oxford Cryostream	3226 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.025
Graphite monochromator	θ_max = 36.3°, θ_min = 2.8°
ω and ϕ scans	h = −10→10
22479 measured reflections	k = −28→26
4255 independent reflections	l = −13→13

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.120	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0585P)² + 0.2019P] where P = (F_o² + 2F_c²)/3
4255 reflections	(Δ/σ)_max < 0.001
147 parameters	Δρ_max = 0.62 e Å⁻³
0 restraints	Δρ_min = −0.32 e Å⁻³

Crystal data top

C₉H₉NO₅	V = 895.6 (2) Å³
M_r = 211.17	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 6.6598 (10) Å	µ = 0.13 mm⁻¹
b = 16.815 (2) Å	T = 90 K
c = 8.0491 (11) Å	0.40 × 0.30 × 0.15 mm
β = 96.485 (7)°

Data collection top

Nonius KappaCCD diffractometer with Oxford Cryostream	3226 reflections with I > 2σ(I)
22479 measured reflections	R_int = 0.025
4255 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.042	0 restraints
wR(F²) = 0.120	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.62 e Å⁻³
4255 reflections	Δρ_min = −0.32 e Å⁻³
147 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	0.70859 (9)	0.17341 (4)	0.57565 (8)	0.01682 (13)
H1O	0.805 (2)	0.1965 (9)	0.5277 (18)	0.025*
O2	0.40131 (9)	0.12263 (4)	0.70993 (9)	0.01727 (13)
O3	0.03482 (9)	0.36827 (4)	0.88871 (9)	0.01850 (14)
O4	0.90549 (10)	0.29612 (4)	0.48481 (9)	0.02148 (15)
O5	0.81333 (10)	0.41618 (4)	0.53665 (9)	0.02082 (14)
N1	0.79036 (11)	0.34401 (4)	0.54412 (9)	0.01483 (13)
C1	0.32973 (11)	0.33924 (5)	0.76315 (10)	0.01274 (14)
C2	0.29375 (12)	0.25663 (5)	0.77082 (10)	0.01340 (14)
H2	0.1831 (18)	0.2368 (8)	0.8237 (15)	0.016*
C3	0.42194 (12)	0.20294 (5)	0.70775 (10)	0.01312 (14)
C4	0.59325 (12)	0.22979 (5)	0.63245 (10)	0.01309 (14)
C5	0.62316 (11)	0.31230 (5)	0.62424 (10)	0.01315 (14)
C6	0.49407 (12)	0.36689 (5)	0.68977 (10)	0.01365 (14)
H6	0.5227 (18)	0.4219 (8)	0.6815 (15)	0.016*
C7	0.22582 (13)	0.09248 (5)	0.77728 (12)	0.01791 (16)
H7A	0.2325	0.1066	0.8959	0.027*
H7B	0.2211	0.0345	0.7654	0.027*
H7C	0.1041	0.1158	0.7165	0.027*
C8	0.18762 (12)	0.39440 (5)	0.83692 (10)	0.01404 (14)
C9	0.23465 (14)	0.48181 (5)	0.84358 (12)	0.01944 (17)
H9A	0.2105	0.5043	0.7308	0.029*
H9B	0.3766	0.4897	0.8876	0.029*
H9C	0.1476	0.5084	0.9167	0.029*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0147 (3)	0.0152 (3)	0.0220 (3)	0.0018 (2)	0.0084 (2)	−0.0013 (2)
O2	0.0163 (3)	0.0115 (3)	0.0255 (3)	−0.0003 (2)	0.0087 (2)	0.0008 (2)
O3	0.0156 (3)	0.0183 (3)	0.0233 (3)	−0.0003 (2)	0.0094 (2)	−0.0002 (2)
O4	0.0179 (3)	0.0203 (3)	0.0287 (3)	−0.0003 (2)	0.0136 (3)	−0.0035 (3)
O5	0.0232 (3)	0.0155 (3)	0.0257 (3)	−0.0043 (2)	0.0110 (3)	0.0008 (2)
N1	0.0137 (3)	0.0163 (3)	0.0152 (3)	−0.0018 (2)	0.0047 (2)	−0.0004 (2)
C1	0.0120 (3)	0.0131 (3)	0.0137 (3)	0.0005 (2)	0.0036 (2)	0.0006 (2)
C2	0.0123 (3)	0.0135 (3)	0.0150 (3)	−0.0002 (2)	0.0042 (2)	0.0007 (3)
C3	0.0124 (3)	0.0126 (3)	0.0148 (3)	−0.0004 (2)	0.0033 (2)	0.0009 (3)
C4	0.0118 (3)	0.0144 (3)	0.0135 (3)	0.0008 (2)	0.0033 (2)	−0.0004 (3)
C5	0.0111 (3)	0.0152 (3)	0.0139 (3)	−0.0015 (2)	0.0044 (2)	0.0002 (3)
C6	0.0133 (3)	0.0135 (3)	0.0147 (3)	−0.0003 (2)	0.0038 (2)	0.0005 (3)
C7	0.0172 (3)	0.0152 (3)	0.0223 (4)	−0.0020 (3)	0.0065 (3)	0.0023 (3)
C8	0.0136 (3)	0.0146 (3)	0.0145 (3)	0.0013 (2)	0.0039 (3)	0.0012 (3)
C9	0.0201 (4)	0.0134 (3)	0.0264 (4)	0.0013 (3)	0.0095 (3)	0.0010 (3)

Geometric parameters (Å, º) top

O1—C4	1.3330 (10)	C2—H2	0.952 (12)
O1—H1O	0.878 (14)	C3—C4	1.4245 (11)
O2—C3	1.3576 (10)	C4—C5	1.4043 (12)
O2—C7	1.4352 (11)	C5—C6	1.4008 (11)
O3—C8	1.2240 (10)	C6—H6	0.948 (13)
O4—N1	1.2438 (10)	C7—H7A	0.9800
O5—N1	1.2255 (10)	C7—H7B	0.9800
N1—C5	1.4499 (10)	C7—H7C	0.9800
C1—C6	1.3817 (11)	C8—C9	1.5026 (12)
C1—C2	1.4120 (12)	C9—H9A	0.9800
C1—C8	1.4952 (11)	C9—H9B	0.9800
C2—C3	1.3783 (11)	C9—H9C	0.9800

C4—O1—H1O	108.5 (10)	C4—C5—N1	120.29 (7)
C3—O2—C7	116.37 (7)	C1—C6—C5	119.34 (8)
O5—N1—O4	122.44 (7)	C1—C6—H6	122.2 (7)
O5—N1—C5	119.50 (7)	C5—C6—H6	118.4 (7)
O4—N1—C5	118.06 (7)	O2—C7—H7A	109.5
C6—C1—C2	119.75 (7)	O2—C7—H7B	109.5
C6—C1—C8	121.91 (7)	H7A—C7—H7B	109.5
C2—C1—C8	118.34 (7)	O2—C7—H7C	109.5
C3—C2—C1	120.87 (7)	H7A—C7—H7C	109.5
C3—C2—H2	118.5 (8)	H7B—C7—H7C	109.5
C1—C2—H2	120.6 (8)	O3—C8—C1	120.03 (8)
O2—C3—C2	125.38 (7)	O3—C8—C9	121.13 (8)
O2—C3—C4	114.07 (7)	C1—C8—C9	118.83 (7)
C2—C3—C4	120.55 (7)	C8—C9—H9A	109.5
O1—C4—C5	126.60 (7)	C8—C9—H9B	109.5
O1—C4—C3	116.15 (7)	H9A—C9—H9B	109.5
C5—C4—C3	117.24 (7)	C8—C9—H9C	109.5
C6—C5—C4	122.23 (7)	H9A—C9—H9C	109.5
C6—C5—N1	117.47 (7)	H9B—C9—H9C	109.5

C6—C1—C2—C3	0.78 (12)	C3—C4—C5—N1	−177.86 (7)
C8—C1—C2—C3	−178.74 (7)	O5—N1—C5—C6	0.14 (12)
C7—O2—C3—C2	2.89 (12)	O4—N1—C5—C6	−179.69 (7)
C7—O2—C3—C4	−177.15 (7)	O5—N1—C5—C4	179.34 (8)
C1—C2—C3—O2	179.60 (8)	O4—N1—C5—C4	−0.48 (12)
C1—C2—C3—C4	−0.36 (12)	C2—C1—C6—C5	−0.15 (12)
O2—C3—C4—O1	−0.18 (10)	C8—C1—C6—C5	179.35 (7)
C2—C3—C4—O1	179.78 (7)	C4—C5—C6—C1	−0.92 (12)
O2—C3—C4—C5	179.38 (7)	N1—C5—C6—C1	178.27 (7)
C2—C3—C4—C5	−0.66 (12)	C6—C1—C8—O3	174.11 (8)
O1—C4—C5—C6	−179.19 (8)	C2—C1—C8—O3	−6.38 (12)
C3—C4—C5—C6	1.31 (12)	C6—C1—C8—C9	−5.00 (12)
O1—C4—C5—N1	1.65 (13)	C2—C1—C8—C9	174.51 (8)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O4	0.878 (14)	1.850 (15)	2.5939 (10)	141.3 (13)
O1—H1O···O3ⁱ	0.878 (14)	2.271 (14)	2.8660 (9)	124.9 (12)
C2—H2···O4ⁱⁱ	0.952 (12)	2.439 (12)	3.3831 (12)	171.4 (11)

Symmetry codes: (i) x+1, −y+1/2, z−1/2; (ii) x−1, −y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	C₉H₉NO₅
M_r	211.17
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	90
a, b, c (Å)	6.6598 (10), 16.815 (2), 8.0491 (11)
β (°)	96.485 (7)
V (Å³)	895.6 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.13
Crystal size (mm)	0.40 × 0.30 × 0.15

Data collection
Diffractometer	Nonius KappaCCD diffractometer with Oxford Cryostream
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	22479, 4255, 3226
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.833

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.120, 1.04
No. of reflections	4255
No. of parameters	147
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.62, −0.32

Computer programs: COLLECT (Nonius, 2000), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O4	0.878 (14)	1.850 (15)	2.5939 (10)	141.3 (13)
O1—H1O···O3ⁱ	0.878 (14)	2.271 (14)	2.8660 (9)	124.9 (12)
C2—H2···O4ⁱⁱ	0.952 (12)	2.439 (12)	3.3831 (12)	171.4 (11)

Symmetry codes: (i) x+1, −y+1/2, z−1/2; (ii) x−1, −y+1/2, z+1/2.

Acknowledgements

We thank Dr Michelle Claville for helpful discussions, Ms Bianca King for help with the melting-point determination and Mr Joseph Allison for help with the GC–MS–EI analysis. This publication was made possible by National Science Foundation (NSF) grant HRD 0450375 (from the HBCU-RISE program) and US Department of Education grant PO31B040030 (Title III, Part B - Strengthening Historically Black Graduate Institutions). The LBRN summer fellowship [provided as part of National Institutes of Health (NIH) grant P20 RR16456] to Sainath Babu is gratefully acknowledged. The contents of this publication are solely the responsibility of authors and do not necessarily represent the official views of the NSF, NIH or the US Department of Education. The purchase of the diffractometer was made possible by grant No. LEQSF (1999–2000)-ENH-TR-13, administered by the Louisiana Board of Regents.

References

Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Web of Science CrossRef CAS IUCr Journals Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Gernapudi, R., Babu, S., Raghavamenon, A. C. & Uppu, R. M. (2009). FASEB J. 23, LB397. Google Scholar
Geronikaki, A. A. & Gavalas, A. M. (2006). Comb. Chem. High Throughput Screen. 9, 425–442. Web of Science CrossRef PubMed CAS Google Scholar
Hayashi, T., Juliet, P. A., Kano-Hayashi, H., Tsunekawa, T., Dingqunfang, D., Sumi, D., Matsui-Hirai, H., Fukatsu, A. & Iguchi, A. (2005). Diabetes Obes. Metab. 7, 334–343. Web of Science CrossRef PubMed CAS Google Scholar
Heumuller, S., Wind, S., Barbosa-Sicard, E., Schmidt, H. H., Busse, R., Schroder, K. & Brandes, R. P. (2008). Hypertension, 51, 211–217. Web of Science CrossRef PubMed Google Scholar
Matés, J. M., Segura, J. A., Alonso, F. J. & Mαrquez, J. (2009). Mini Rev. Med. Chem. Aug 1. [Epub ahead of print]. Google Scholar
Muijsers, R. B. R., va Ark, I. I., Folkerts, G., Koster, A. S., van Oosterhout, A. J., Postma, D. S. & Nijkamp, F. P. (2001). Br. J. Pharmacol. 134, 434–440. Web of Science CrossRef PubMed CAS Google Scholar
Nonius (2000). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Sawa, T., Akaike, T. & Maeda, H. (2000). J. Biol. Chem. 275, 32467–32474. Web of Science CrossRef PubMed CAS Google Scholar
Schopfer, F. J., Baker, P. R. S. & Freeman, B. A. (2003). Trends Biochem. Sci. 28, 646–654. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stefanska, J. & Pawliczak, R. (2008). Mediators Inflamm. doi: 10.1155/2008/106507. Google Scholar
Stolk, J., Hiltermann, T. J., Dijkman, J. H. & Verhoeven, A. J. (1994). Am. J. Respir. Cell Mol. Biol. 11, 95–102. CrossRef CAS PubMed Web of Science Google Scholar
Tajik, H., Niknam, & Parsa, F. (2009). J. Iran. Chem. Soc, 6, 159–164. Google Scholar
Thomas, D. D., Espey, M. G., Vitek, M. P., Miranda, K. M. & Wink, D. A. (2002). Proc. Natl Acad. Sci. USA, 99, 12691–12696. Web of Science CrossRef PubMed CAS Google Scholar
Touyz, R. M. (2008). Hypertension, 51, 172–174. Web of Science CrossRef PubMed CAS Google Scholar
Ximenes, V. F., Kanegae, M. P. P., Rissato, S. R. & Galhiane, M. S. (2007). Arch. Biochem. Biophys. 457, 134–141. Web of Science CrossRef PubMed CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 9| September 2009| Pages o2292-o2293

doi:10.1107/S160053680903390X

Open

access