PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2009 July 1; 65(Pt 7): o1604–o1605.
Published online 2009 June 17. doi:  10.1107/S1600536809022302
PMCID: PMC2969188

2-(1H-Benzimidazol-1-yl)-1-(2-fur­yl)ethanone O-isopropyl­oxime

Abstract

In the mol­ecule of the title compound, C16H17N3O2, the planar benzimidazole ring system [maximum deviation = 0.015 (2) Å] is oriented at a dihedral angle of 72.17 (4)° with respect to the furan ring. An intra­molecular C—H(...)O inter­action results in the formation of a six-membered ring having an envelope conformation. In the crystal structure, inter­molecular C—H(...)N inter­actions link the mol­ecules into centrosymmetric R 2 2(18) dimers.

Related literature

For general background to oximes and oxime ethers, including their biological activity, see: Baji et al. (1995 [triangle]); Bhandari et al. (2009 [triangle]); Emami et al. (2002 [triangle], 2004 [triangle]); Milanese et al. (2007 [triangle]); Polak (1982 [triangle]); Poretta et al. (1993 [triangle]); Ramalingan et al. (2006 [triangle]); Rosello et al. (2002 [triangle]). For related structures, see: Özel Güven et al. (2007a [triangle],b [triangle], 2009 [triangle]). For ring-motifs, see: Bernstein et al. (1995 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o1604-scheme1.jpg

Experimental

Crystal data

  • C16H17N3O2
  • M r = 283.33
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o1604-efi1.jpg
  • a = 8.4290 (2) Å
  • b = 17.7606 (3) Å
  • c = 10.6017 (2) Å
  • β = 111.882 (1)°
  • V = 1472.77 (5) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 120 K
  • 0.40 × 0.20 × 0.20 mm

Data collection

  • Bruker–Nonius KappaCCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2007 [triangle]) T min = 0.966, T max = 0.979
  • 20597 measured reflections
  • 3356 independent reflections
  • 2803 reflections with I > 2σ(I)
  • R int = 0.035

Refinement

  • R[F 2 > 2σ(F 2)] = 0.042
  • wR(F 2) = 0.111
  • S = 1.12
  • 3356 reflections
  • 259 parameters
  • All H-atom parameters refined
  • Δρmax = 0.27 e Å−3
  • Δρmin = −0.28 e Å−3

Data collection: COLLECT (Hooft, 1998 [triangle]); cell refinement: DENZO (Otwinowski & Minor, 1997 [triangle]) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]) and PLATON (Spek, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809022302/im2123sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809022302/im2123Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors acknowledge the Zonguldak Karaelmas University Research Fund (Project No. 2007/2–13–02–09).

supplementary crystallographic information

Comment

Oximes and oxime ethers show very important antifungal and antibacterial activities. Oxiconazole is a well established drug for treatment of many mycotic infections, having an oxime group (Polak, 1982). Several compounds containing an oxime or an oxime ether function have been reported to exhibit antimicrobial activity (Poretta et al., 1993; Baji et al., 1995; Rosello et al., 2002; Emami et al., 2002; Emami et al., 2004; Ramalingan et al., 2006; Milanese et al., 2007; Bhandari et al., 2009). In our earlier studies, we reported X-ray structures of benzimidazole substituted oxiconazole derivatives (Özel Güven et al., 2007a; 2007b; 2009). Now, we report herein the crystal structure of the title alkyl oxime ether.

In the molecule of the title compound (Fig. 1), the bond lengths and angles are generally within normal ranges. The planar benzimidazole ring system [with a maximum deviation of 0.015 (2) Å for atom C5] is oriented with respect to the furan ring at a dihedral angle of 72.17 (4)°. Atoms C8 and C9 are -0.037 (1) and 0.008 (1) Å away from the furan ring plane, respectively, while atom C8 is at a distance of -0.008 (1) Å to the benzimidazole ring plane. So, they are coplanar with the adjacent rings. The N1—C1—N2 [114.1 (1)°], N2—C2—C7 [110.2 (1)°], C2—C7—C6 [122.8 (1)°], C3—C4—C5 [121.7 (1)°] and C4—C5—C6 [121.8 (1)°] bond angles are enlarged, while C5—C6—C7 [116.2 (1)°] and C2—C3—C4 [117.5 (1)°] bond angles are narrowed. An Intramolecular C—H···O interaction (Table 1) results in the formation of a six-membered ring, (O2/N3/C9—C11/H11), having envelope conformation with atom H11 displaced by -0.126 (15) Å from the plane of the other ring atoms.

In the crystal structure, intermolecular C—H···N interactions (Table 1) link the molecules into centrosymmetric dimers exhibiting R22(18) ring motifs (Bernstein et al., 1995) (Fig. 2).

Experimental

The title compound was synthesized by the reaction of 2-(1H-benzimidazol-1-yl)-1-(furan-2-yl)ethanone oxime obtained from 2-(1H-benzimidazol-1-yl)-1-(furan-2-yl)ethanone (Özel Güven et al., 2007b) with iso-propyl bromide and NaH. To a solution of 2-(1H-benzimidazol-1-yl)-1-(furan-2-yl)ethanone oxime (400 mg, 1.658 mmol) in DMF (5 ml) was added NaH (66 mg, 1.658 mmol) in small fractions. Then, iso-propyl bromide (204 mg, 1.658 mmol) was added dropwise. The mixture was stirred at room temperature for 3 h and the excess of hydride was decomposed with a small amount of methanol. After evaporation to dryness under reduced pressure, the crude residue was suspended with water and extracted with methylene chloride. The organic layer was dried over anhydrous sodium sulfate and then evaporated to dryness. The crude residue was purified by chromatography on a silica-gel column using chloroform and recrystallized from ethyl acetate to obtain yellow crystals (yield; 126 mg, 27%).

Refinement

All H atoms were located from difference Fourier syntheses and refined isotropically [C—H = 0.948 (17)–1.057 (18) Å, Uiso(H) = 0.022 (3)–0.061 (6) Å2].

Figures

Fig. 1.
The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bond is shown as dashed line.
Fig. 2.
A partial packing diagram of the title compound. Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted for clarity.

Crystal data

C16H17N3O2F(000) = 600
Mr = 283.33Dx = 1.278 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3444 reflections
a = 8.4290 (2) Åθ = 2.9–27.5°
b = 17.7606 (3) ŵ = 0.09 mm1
c = 10.6017 (2) ÅT = 120 K
β = 111.882 (1)°Plate, yellow
V = 1472.77 (5) Å30.40 × 0.20 × 0.20 mm
Z = 4

Data collection

Bruker–Nonius KappaCCD diffractometer3356 independent reflections
Radiation source: fine-focus sealed tube2803 reflections with I > 2σ(I)
graphiteRint = 0.035
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 3.1°
[var phi] and ω scansh = −10→10
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)k = −23→23
Tmin = 0.966, Tmax = 0.979l = −13→12
20597 measured reflections

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.042All H-atom parameters refined
wR(F2) = 0.111w = 1/[σ2(Fo2) + (0.0577P)2 + 0.2982P] where P = (Fo2 + 2Fc2)/3
S = 1.12(Δ/σ)max < 0.001
3356 reflectionsΔρmax = 0.27 e Å3
259 parametersΔρmin = −0.28 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.091 (6)

Special details

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)

xyzUiso*/Ueq
O10.58682 (11)0.47550 (5)0.80555 (8)0.0252 (2)
O20.41827 (11)0.33276 (5)1.02341 (8)0.0247 (2)
N10.19899 (13)0.45752 (5)0.64047 (9)0.0205 (2)
N20.18669 (14)0.44880 (6)0.42568 (10)0.0278 (3)
N30.30106 (13)0.38505 (6)0.94150 (10)0.0226 (2)
C10.25496 (17)0.48323 (7)0.54285 (12)0.0244 (3)
H10.3367 (18)0.5250 (8)0.5619 (14)0.025 (3)*
C20.07716 (15)0.39595 (7)0.44673 (12)0.0241 (3)
C3−0.03026 (17)0.34334 (8)0.35695 (13)0.0318 (3)
H3−0.032 (2)0.3408 (9)0.2646 (17)0.038 (4)*
C4−0.12897 (19)0.29830 (9)0.40499 (15)0.0386 (4)
H4−0.203 (2)0.2612 (11)0.3450 (18)0.051 (5)*
C5−0.12247 (18)0.30444 (8)0.53863 (15)0.0360 (3)
H5−0.196 (2)0.2724 (10)0.5696 (17)0.045 (5)*
C6−0.01575 (16)0.35542 (7)0.62975 (14)0.0282 (3)
H6−0.0111 (19)0.3597 (8)0.7232 (16)0.031 (4)*
C70.08317 (14)0.40074 (6)0.58065 (11)0.0212 (3)
C80.25028 (16)0.48361 (7)0.78092 (12)0.0222 (3)
H810.3035 (17)0.5328 (8)0.7868 (13)0.022 (3)*
H820.1471 (19)0.4885 (8)0.8028 (14)0.026 (4)*
C90.37140 (15)0.42870 (6)0.87967 (11)0.0197 (3)
C100.54860 (15)0.42703 (6)0.89174 (11)0.0198 (3)
C110.69233 (16)0.38863 (7)0.96787 (12)0.0236 (3)
H110.6964 (19)0.3507 (9)1.0364 (15)0.030 (4)*
C120.82605 (17)0.41455 (7)0.92724 (13)0.0289 (3)
H120.941 (2)0.3979 (9)0.9589 (17)0.040 (4)*
C130.75635 (17)0.46619 (8)0.82951 (13)0.0296 (3)
H130.799 (2)0.4959 (9)0.7728 (16)0.037 (4)*
C140.33484 (16)0.28212 (7)1.08724 (13)0.0265 (3)
H140.219 (2)0.2716 (9)1.0207 (15)0.031 (4)*
C150.3264 (3)0.31843 (10)1.21285 (18)0.0463 (4)
H1510.446 (3)0.3321 (12)1.281 (2)0.061 (6)*
H1520.254 (3)0.3634 (12)1.189 (2)0.060 (6)*
H1530.272 (3)0.2848 (11)1.2585 (19)0.060 (5)*
C160.44161 (18)0.21125 (8)1.11657 (14)0.0316 (3)
H1610.446 (2)0.1863 (10)1.0273 (18)0.048 (5)*
H1620.398 (2)0.1768 (10)1.1676 (18)0.048 (5)*
H1630.559 (2)0.2239 (9)1.1768 (17)0.040 (4)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0290 (5)0.0255 (4)0.0222 (4)−0.0023 (3)0.0109 (4)0.0052 (3)
O20.0236 (5)0.0258 (4)0.0235 (4)−0.0009 (3)0.0075 (3)0.0090 (3)
N10.0244 (5)0.0197 (5)0.0171 (5)0.0029 (4)0.0074 (4)0.0016 (4)
N20.0345 (6)0.0279 (5)0.0204 (5)0.0050 (4)0.0098 (4)0.0049 (4)
N30.0253 (5)0.0231 (5)0.0179 (5)0.0015 (4)0.0063 (4)0.0020 (4)
C10.0310 (7)0.0213 (6)0.0212 (6)0.0025 (5)0.0100 (5)0.0049 (4)
C20.0236 (6)0.0251 (6)0.0200 (6)0.0078 (5)0.0038 (5)0.0027 (4)
C30.0300 (7)0.0332 (7)0.0227 (6)0.0077 (6)−0.0012 (5)−0.0023 (5)
C40.0270 (7)0.0369 (7)0.0388 (8)−0.0018 (6)−0.0029 (6)−0.0080 (6)
C50.0258 (7)0.0353 (7)0.0435 (8)−0.0040 (6)0.0088 (6)0.0002 (6)
C60.0240 (6)0.0307 (6)0.0310 (7)0.0018 (5)0.0115 (5)0.0023 (5)
C70.0189 (6)0.0212 (5)0.0209 (6)0.0057 (4)0.0043 (4)0.0007 (4)
C80.0288 (7)0.0197 (6)0.0185 (6)0.0030 (5)0.0092 (5)−0.0010 (4)
C90.0259 (6)0.0182 (5)0.0146 (5)−0.0004 (4)0.0069 (4)−0.0026 (4)
C100.0272 (6)0.0175 (5)0.0149 (5)−0.0032 (4)0.0082 (4)−0.0014 (4)
C110.0274 (6)0.0226 (6)0.0203 (6)−0.0002 (5)0.0082 (5)0.0004 (4)
C120.0260 (7)0.0323 (7)0.0289 (7)−0.0009 (5)0.0110 (5)0.0000 (5)
C130.0282 (7)0.0340 (7)0.0297 (7)−0.0046 (5)0.0144 (5)0.0010 (5)
C140.0251 (6)0.0283 (6)0.0252 (6)−0.0067 (5)0.0082 (5)0.0061 (5)
C150.0648 (12)0.0454 (9)0.0409 (9)−0.0056 (9)0.0340 (9)0.0029 (7)
C160.0288 (7)0.0292 (7)0.0306 (7)−0.0061 (5)0.0039 (6)0.0094 (5)

Geometric parameters (Å, °)

O1—C101.3782 (13)C6—H60.980 (15)
O1—C131.3650 (16)C8—C91.5142 (16)
O2—N31.3976 (12)C8—H810.973 (14)
O2—C141.4547 (14)C8—H820.984 (15)
N1—C11.3661 (15)C9—C101.4511 (17)
N1—C71.3823 (15)C10—C111.3621 (17)
N1—C81.4625 (15)C11—C121.4247 (18)
N2—C11.3096 (16)C11—H110.981 (15)
N2—C21.3917 (17)C12—H120.948 (17)
N3—C91.2929 (15)C13—C121.3440 (19)
C1—H10.981 (15)C13—H130.964 (17)
C2—C31.3988 (18)C14—C151.505 (2)
C2—C71.4043 (17)C14—H140.988 (16)
C3—C41.381 (2)C15—H1511.02 (2)
C3—H30.974 (16)C15—H1520.98 (2)
C4—H40.966 (19)C15—H1530.98 (2)
C5—C41.402 (2)C16—C141.5107 (19)
C5—H50.983 (17)C16—H1611.057 (18)
C6—C51.3836 (19)C16—H1630.982 (17)
C6—C71.3919 (18)C16—H1620.973 (19)
C13—O1—C10106.74 (9)N3—C9—C10126.47 (10)
N3—O2—C14110.34 (9)N3—C9—C8114.73 (11)
C1—N1—C7106.29 (10)C10—C9—C8118.73 (10)
C1—N1—C8127.66 (10)C11—C10—O1109.24 (10)
C7—N1—C8126.05 (10)C11—C10—C9136.17 (11)
C1—N2—C2104.24 (10)O1—C10—C9114.58 (10)
C9—N3—O2111.22 (9)C10—C11—C12106.75 (11)
N2—C1—N1114.13 (11)C10—C11—H11124.1 (9)
N2—C1—H1125.1 (8)C12—C11—H11129.2 (9)
N1—C1—H1120.7 (8)C13—C12—C11106.61 (12)
N2—C2—C3129.89 (12)C13—C12—H12125.5 (10)
N2—C2—C7110.19 (10)C11—C12—H12127.8 (10)
C3—C2—C7119.91 (12)C12—C13—O1110.65 (11)
C4—C3—C2117.53 (13)C12—C13—H13134.2 (10)
C4—C3—H3123.9 (10)O1—C13—H13115.1 (9)
C2—C3—H3118.6 (10)O2—C14—C15109.71 (11)
C3—C4—C5121.71 (13)O2—C14—C16104.87 (10)
C3—C4—H4118.9 (10)C15—C14—C16113.33 (12)
C5—C4—H4119.4 (10)O2—C14—H14107.9 (9)
C6—C5—C4121.81 (14)C15—C14—H14110.6 (9)
C6—C5—H5118.2 (10)C16—C14—H14110.2 (9)
C4—C5—H5120.0 (10)C14—C15—H151111.3 (11)
C5—C6—C7116.20 (12)C14—C15—H152110.8 (12)
C5—C6—H6121.9 (9)H151—C15—H152109.8 (17)
C7—C6—H6121.9 (9)C14—C15—H153111.1 (11)
N1—C7—C6132.02 (11)H151—C15—H153108.3 (15)
N1—C7—C2105.14 (10)H152—C15—H153105.3 (16)
C6—C7—C2122.83 (11)C14—C16—H161112.4 (9)
N1—C8—C9111.54 (9)C14—C16—H163108.7 (10)
N1—C8—H82108.4 (8)H161—C16—H163108.5 (14)
C9—C8—H82108.8 (8)C14—C16—H162108.6 (11)
N1—C8—H81107.7 (8)H161—C16—H162112.2 (14)
C9—C8—H81111.0 (8)H163—C16—H162106.1 (14)
H82—C8—H81109.4 (12)
C13—O1—C10—C110.18 (12)C7—C2—C3—C40.80 (18)
C13—O1—C10—C9−179.51 (10)N2—C2—C7—N1−0.13 (13)
C10—O1—C13—C12−0.41 (14)C3—C2—C7—N1−179.70 (10)
C14—O2—N3—C9−177.47 (9)N2—C2—C7—C6178.84 (11)
N3—O2—C14—C15−82.98 (13)C3—C2—C7—C6−0.73 (18)
N3—O2—C14—C16155.00 (9)C2—C3—C4—C5−0.2 (2)
C7—N1—C1—N20.10 (14)C6—C5—C4—C3−0.6 (2)
C8—N1—C1—N2179.73 (11)C7—C6—C5—C40.7 (2)
C1—N1—C7—C6−178.81 (12)C5—C6—C7—N1178.63 (12)
C8—N1—C7—C61.55 (19)C5—C6—C7—C2−0.03 (18)
C1—N1—C7—C20.03 (12)N1—C8—C9—N3−100.58 (12)
C8—N1—C7—C2−179.62 (10)N1—C8—C9—C1076.58 (13)
C1—N1—C8—C9−104.20 (13)N3—C9—C10—C11−5.0 (2)
C7—N1—C8—C975.38 (14)C8—C9—C10—C11178.23 (12)
C2—N2—C1—N1−0.17 (14)N3—C9—C10—O1174.60 (10)
C1—N2—C2—C3179.70 (12)C8—C9—C10—O1−2.19 (14)
C1—N2—C2—C70.18 (13)O1—C10—C11—C120.10 (13)
O2—N3—C9—C10−1.02 (15)C9—C10—C11—C12179.69 (12)
O2—N3—C9—C8175.89 (9)C10—C11—C12—C13−0.34 (14)
N2—C2—C3—C4−178.67 (12)O1—C13—C12—C110.46 (15)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C11—H11···O20.98 (2)2.32 (2)2.772 (2)107 (1)
C13—H13···N2i0.96 (2)2.37 (2)3.286 (2)159 (1)

Symmetry codes: (i) −x+1, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IM2123).

References

  • Baji, H., Flammang, M., Kimny, T., Gasquez, F., Compagnon, P. L. & Delcourt, A. (1995). Eur. J. Med. Chem.30, 617–626.
  • Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl.34, 1555–1573.
  • Bhandari, K., Srinivas, N., Shiva Keshava, G. B. & Shukla, P. K. (2009). Eur. J. Med. Chem.44, 437-447. [PubMed]
  • Emami, S., Falahatti, M., Banifatemi, A., Moshiri, K. & Shafiee, A. (2002). Arch. Pharm.335, 318–324. [PubMed]
  • Emami, S., Falahatti, M., Banifatemi, A., Moshiri, K. & Shafiee, A. (2004). Bioorg. Med. Chem.12, 5881–5889. [PubMed]
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Hooft, R. W. W. (1998). COLLECT Nonius BV, Delft, The Netherlands.
  • Milanese, L., Giacche, N., Schiaffella, F., Vecchiarelli, A., Macchiarulo, A. & Fringuelli, R. (2007). ChemMedChem, 2, 1208–1213. [PubMed]
  • 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.
  • Özel Güven, Ö., Erdoğan, T., Çaylak, N. & Hökelek, T. (2007a). Acta Cryst. E63, o4090–o4091.
  • Özel Güven, Ö., Erdoğan, T., Coles, S. J. & Hökelek, T. (2009). Acta Cryst. E65, o1517–o1518. [PMC free article] [PubMed]
  • Özel Güven, Ö., Erdoğan, T., Göker, H. & Yıldız, S. (2007b). J. Heterocycl. Chem.44, 731–734.
  • Polak, A. (1982). Arzneim. Forsch. Drug Res.32, 17–24. [PubMed]
  • Poretta, G. C., Fioravanti, R., Biava, M., Cirilli, R., Simonetti, N., Villa, A., Bello, U., Faccendini, P. & Tita, B. (1993). Eur. J. Med. Chem.28, 749–760.
  • Ramalingan, C., Park, Y. T. & Kabilan, S. (2006). Eur. J. Med. Chem.41, 683–696. [PubMed]
  • Rosello, A., Bertini, S., Lapucci, A., Macchia, M., Martinelli, A., Rapposelli, S., Herreros, E. & Macchia, B. (2002). J. Med. Chem.45, 4903–4912. [PubMed]
  • Sheldrick, G. M. (2007). SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography