Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Previous article
Next article
Previous article
Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Next article

organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 5| May 2009| Page o1170
doi:10.1107/S1600536809015463

1-(4-Meth­oxy­phen­yl)-3-phenyl-1H-pyrazol-5-amine

Isuru R. Kumarasinghe,a Victor J. Hrubya and Gary S. Nichola*

aDepartment of Chemistry, The University of Arizona, 1306 E. University Boulevard, Tucson, AZ 85721, USA
*Correspondence e-mail: gsnichol@email.arizona.edu

(Received 21 April 2009; accepted 25 April 2009; online 30 April 2009)

The synthesis of the title compound, C16H15N3O, is regiospecific and single-crystal X-ray diffraction provides the only means of unambiguous structural analysis, with the benzene ring bonded to the imine C atom. The phenyl ring and the essentially planar (r.m.s. deviation 0.0354 Å) methoxy­benzene group are rotated by 29.41 (5) and 37.01 (5)°, respectively, from the central pyrazole ring. An inter­molecular N—H⋯N hydrogen bond links symmetry-related mol­ecules into a C(5) chain, which runs parallel to the b axis.

Related literature

For background to this study, see: Gavrin et al. (2007[Gavrin, L. K., Lee, A., Provencher, B. A., Massefski, W. W., Huhn, S. D., Ciszewski, G. M., Cole, D. C. & McKew, J. C. (2007). J. Org. Chem., 72, 1043-1046.]); Joshi et al. (1979[Joshi, K. C., Pathak, V. N. & Garg, U. (1979). J. Heterocycl. Chem. 16, 1141-1145.]); Michaux & Charlier (2004[Michaux, C. & Charlier, C. (2004). Mini-Rev. Med. Chem. 4, 603-615.]); Ossipov et al. (2004[Ossipov, M. H., Lai, J., King, T., Vanderah, T. W., Malan, T. P., Hruby, V. J. & Porreca, F. (2004). J. Neurobiol. 61, 126-148.]); Raffa (2001[Raffa, R. B. (2001). J. Clin. Pharm. Ther. 26, 257-264.]).

[Scheme 1]

Experimental

Crystal data

  • C16H15N3O

  • Mr = 265.31

  • Orthorhombic, P b c a

  • a = 14.9638 (6) Å

  • b = 6.3639 (2) Å

  • c = 28.2466 (12) Å

  • V = 2689.87 (18) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 296 K

  • 0.35 × 0.35 × 0.05 mm
Data collection

  • Bruker Kappa APEXII diffractometer

  • Absorption correction: none

  • 11632 measured reflections

  • 3019 independent reflections

  • 2256 reflections with I > 2σ(I)

  • Rint = 0.031
Refinement

  • R[F2 > 2σ(F2)] = 0.044

  • wR(F2) = 0.111

  • S = 1.02

  • 3019 reflections

  • 190 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.20 e Å−3

  • Δρmin = −0.15 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
N3—H3NA⋯N2i 0.89 (2) 2.37 (2) 3.228 (2) 162.5 (16)
Symmetry code: (i) x, y-1, z.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXTL and local programs.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809015463/lh2810sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809015463/lh2810Isup2.hkl

checkCIF report


Comment top

It has been pharmacologically shown that co-administration of opioids with cyclooxygenase (COX) inhibitors is synergistic and reduces development of drug tolerance (Raffa, 2001; Ossipov et al., 2004). The creation of bifunctional molecules having both COX2 inhibitory activity and Opioid mu agonist activity is a promising approach to retain better analgesic properties. We are investigating plausible COX2 pharmacophores that can be obtained for bifunctional design using known organic reactions. Based on the evidence so far (Joshi et al.,1979; Gavrin et al., 2007) we probed whether the reaction between hydrazine derivatives and benzoylacetonitrile will usefully yield pyrazoles as a product substituted with 1,5-vicinal diaryls, which is an important structural feature for COX2 inhibitory activity (Michaux & Charlier, 2004). We observed that the reaction between benzoylacetonitrile with 2-(4-methoxyphenyl)hydraziniumchloride is regiospecific which means it provides solely 1-(4-methoxyphenyl)-3-phenyl-1H-pyrazol-5-amine, (I), which is undesired for our purpose. Furthermore it cannot be correctly identified with one-dimensional nuclear Overhauser effect or two-dimensional heteronuclear multiple bond correlation spectroscopic methods, leaving single-crystal X-ray diffraction as the only possible means of unambiguous identification of the compound.

The molecular structure of (I) is shown in Figure 1. Two regioisomers were possible and here the structure is unambiguous with the phenyl ring (C11-C16) bonded to the imine carbon atom C1. Molecular dimensions are unexceptional. The methoxybenzyl group is essentially planar (r.m.s. deviation of a mean plane fitted through C4 to C10 and O is 0.0354 Å) and is rotated by 37.01 (5)° from the central pyrazole ring. The phenyl ring (C11-C16) is rotated by 29.41 (5)° from the central pyrazole ring. A lone N–H···N hydrogen bond links the molecules into a C(5) chain which runs parallel to the b axis(Figure 2).

Related literature top

For background to this study, see: Gavrin et al. (2007); Joshi et al. (1979); Michaux & Charlier (2004); Ossipov et al. (2004); Raffa (2001).

Experimental top

Benzoylacetonitrile (1.45 g, 10 mmol) in 50 ml of absolute ethanol was treated with 2-(4-methoxyphenyl) hydraziniumchloride (1.75 g, 10 mmol) under reflux for 1 day. The solvent was then removed by rotary evaporation and the residue was extracted with a 1:1 mix of dichloromethane and H2O. The organic layer was separated and dried with anhydrous MgSO4, filtered and then the solvent removed by rotary evaporation to leave a vrown residue. This was washed with hexane and recrystallized from dichloromethane. C16H15N3O, (I), yield = 90%. TOF MS EI m/z 264.9839. 1H NMR (CDCl3)δ 3.85 (s, 3H), 5.95 (s, 1H), 7.0 (d,2H), 7.25 (m,1H), 7.4 (t,2H) 7.5(d,2H), 7.8 (d,2H) 13CNMR (CDCl3) δ 55.50, 87.59, 114.61, 125. 522, 126.049, 127.626, 128.391, 131.463,133.551, 145.740, 151.043, 158.971

Refinement top

Amine hydrogen atoms were freely refined. Aryl hydrogen atoms were refined with Uiso(H) = 1.2 Ueq(C) and a fixed C–H distance of 0.93 Å; methyl hydrogen atoms were refined with Uiso(H) = 1.5 Ueq(C) and a fixed C–H distance of 0.96 Å.

Computing details top

Data collection: APEX2 (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: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and local programs.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with displacement ellipsoids at the 50% probability level.
[Figure 2] Fig. 2. Part of the crystal structure of (I) showing a hydrogen bonded (dashed lines) chain.
1-(4-Methoxyphenyl)-3-phenyl-1H-pyrazol-5-amine top
Crystal data top
C16H15N3OF(000) = 1120
Mr = 265.31Dx = 1.310 Mg m−3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 2475 reflections
a = 14.9638 (6) Åθ = 2.7–28.6°
b = 6.3639 (2) ŵ = 0.09 mm−1
c = 28.2466 (12) ÅT = 296 K
V = 2689.87 (18) Å3Plate, colourless
Z = 80.35 × 0.35 × 0.05 mm
Data collection top
Bruker Kappa APEXII
diffractometer		2256 reflections with I > 2σ(I)
Radiation source: sealed tubeRint = 0.031
Graphite monochromatorθmax = 28.3°, θmin = 2.0°
ϕ and ω scansh = −19→16
11632 measured reflectionsk = −7→6
3019 independent reflectionsl = −36→37
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: difference Fourier map
wR(F2) = 0.111H atoms treated by a mixture of independent and constrained refinement
S = 1.02 w = 1/[σ2(Fo2) + (0.048P)2 + 0.671P]
where P = (Fo2 + 2Fc2)/3
3019 reflections(Δ/σ)max = 0.001
190 parametersΔρmax = 0.20 e Å−3
0 restraintsΔρmin = −0.15 e Å−3
Crystal data top
C16H15N3OV = 2689.87 (18) Å3
Mr = 265.31Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 14.9638 (6) ŵ = 0.09 mm−1
b = 6.3639 (2) ÅT = 296 K
c = 28.2466 (12) Å0.35 × 0.35 × 0.05 mm
Data collection top
Bruker Kappa APEXII
diffractometer		2256 reflections with I > 2σ(I)
11632 measured reflectionsRint = 0.031
3019 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.111H atoms treated by a mixture of independent and constrained refinement
S = 1.02Δρmax = 0.20 e Å−3
3019 reflectionsΔρmin = −0.15 e Å−3
190 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
xyzUiso*/Ueq
O0.37170 (8)0.3584 (2)0.56552 (3)0.0537 (3)
N10.38199 (8)0.10523 (19)0.75399 (4)0.0327 (3)
N20.37654 (8)0.2595 (2)0.78830 (4)0.0357 (3)
N30.39632 (11)−0.2693 (2)0.74725 (6)0.0506 (4)
H3NA0.3945 (12)−0.386 (3)0.7646 (6)0.057 (6)*
H3NB0.3982 (15)−0.264 (4)0.7192 (8)0.083 (8)*
C10.38472 (9)0.1542 (2)0.82878 (5)0.0334 (3)
C20.39560 (10)−0.0607 (3)0.82140 (5)0.0401 (4)
H20.4031−0.16390.84440.048*
C30.39302 (9)−0.0890 (2)0.77325 (5)0.0359 (3)
C40.37681 (9)0.1656 (2)0.70563 (4)0.0317 (3)
C50.42957 (9)0.0699 (3)0.67137 (5)0.0391 (4)
H50.4681−0.03860.67970.047*
C60.42468 (10)0.1361 (3)0.62484 (5)0.0414 (4)
H60.45860.06880.60180.050*
C70.36981 (9)0.3015 (3)0.61242 (5)0.0379 (4)
C80.31728 (9)0.3982 (2)0.64632 (5)0.0374 (3)
H80.28030.50970.63810.045*
C90.32044 (9)0.3268 (2)0.69274 (4)0.0347 (3)
H90.28400.38870.71550.042*
C100.32253 (15)0.5386 (4)0.55199 (6)0.0687 (6)
H10A0.26040.51750.55910.103*
H10B0.32960.56200.51860.103*
H10C0.34420.65870.56910.103*
C110.38252 (9)0.2644 (3)0.87483 (5)0.0354 (3)
C120.33514 (10)0.4489 (3)0.88095 (5)0.0421 (4)
H120.30410.50730.85560.050*
C130.33371 (12)0.5473 (3)0.92489 (6)0.0534 (4)
H130.30180.67140.92890.064*
C140.37933 (12)0.4620 (3)0.96249 (6)0.0567 (5)
H140.37840.52850.99180.068*
C150.42634 (12)0.2785 (3)0.95670 (5)0.0550 (5)
H150.45710.22070.98220.066*
C160.42822 (11)0.1790 (3)0.91320 (5)0.0448 (4)
H160.46010.05460.90960.054*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O0.0695 (8)0.0595 (9)0.0320 (5)0.0105 (6)0.0029 (5)0.0047 (5)
N10.0413 (6)0.0248 (8)0.0320 (5)−0.0005 (5)−0.0026 (4)−0.0017 (4)
N20.0451 (7)0.0306 (8)0.0315 (5)−0.0003 (5)−0.0004 (5)−0.0021 (5)
N30.0764 (10)0.0275 (9)0.0478 (8)−0.0004 (7)−0.0067 (7)−0.0014 (7)
C10.0349 (7)0.0311 (9)0.0342 (6)−0.0036 (6)0.0004 (5)0.0033 (6)
C20.0495 (8)0.0308 (10)0.0399 (7)−0.0004 (7)−0.0037 (6)0.0071 (6)
C30.0386 (7)0.0260 (9)0.0430 (7)−0.0005 (6)−0.0046 (5)0.0011 (6)
C40.0347 (7)0.0290 (9)0.0315 (6)−0.0037 (6)−0.0026 (5)0.0003 (5)
C50.0389 (7)0.0379 (10)0.0406 (7)0.0068 (6)−0.0009 (6)−0.0013 (6)
C60.0425 (8)0.0448 (11)0.0370 (7)0.0064 (7)0.0045 (6)−0.0061 (6)
C70.0418 (7)0.0405 (10)0.0315 (6)−0.0032 (6)−0.0007 (5)−0.0002 (6)
C80.0427 (8)0.0324 (9)0.0370 (7)0.0053 (6)−0.0031 (5)−0.0006 (6)
C90.0373 (7)0.0327 (9)0.0342 (6)0.0017 (6)0.0012 (5)−0.0048 (6)
C100.0913 (15)0.0668 (16)0.0481 (10)0.0174 (12)−0.0012 (9)0.0197 (9)
C110.0380 (7)0.0355 (10)0.0328 (6)−0.0062 (6)0.0033 (5)0.0032 (6)
C120.0463 (8)0.0394 (10)0.0406 (7)0.0001 (7)0.0015 (6)0.0012 (7)
C130.0587 (10)0.0483 (12)0.0532 (9)0.0046 (8)0.0083 (7)−0.0089 (8)
C140.0659 (11)0.0678 (15)0.0363 (8)−0.0051 (10)0.0071 (7)−0.0104 (8)
C150.0639 (11)0.0683 (15)0.0329 (7)−0.0030 (9)−0.0023 (7)0.0052 (8)
C160.0525 (9)0.0436 (11)0.0382 (7)0.0026 (8)0.0003 (6)0.0046 (7)
Geometric parameters (Å, º) top
O—C71.3736 (16)C7—C81.3834 (19)
O—C101.415 (2)C8—H80.9300
N1—N21.3820 (16)C8—C91.3885 (18)
N1—C31.3607 (19)C9—H90.9300
N1—C41.4211 (16)C10—H10A0.9600
N2—C11.3307 (17)C10—H10B0.9600
N3—H3NA0.89 (2)C10—H10C0.9600
N3—H3NB0.79 (2)C11—C121.382 (2)
N3—C31.363 (2)C11—C161.392 (2)
C1—C21.393 (2)C12—H120.9300
C1—C111.4782 (19)C12—C131.391 (2)
C2—H20.9300C13—H130.9300
C2—C31.373 (2)C13—C141.374 (2)
C4—C51.3896 (19)C14—H140.9300
C4—C91.377 (2)C14—C151.373 (3)
C5—H50.9300C15—H150.9300
C5—C61.3823 (19)C15—C161.383 (2)
C6—H60.9300C16—H160.9300
C6—C71.380 (2)
C7—O—C10117.63 (13)C7—C8—C9119.26 (14)
N2—N1—C3111.85 (11)H8—C8—C9120.4
N2—N1—C4118.61 (12)C4—C9—C8120.95 (13)
C3—N1—C4129.54 (12)C4—C9—H9119.5
N1—N2—C1103.86 (12)C8—C9—H9119.5
H3NA—N3—H3NB126 (2)O—C10—H10A109.5
H3NA—N3—C3113.9 (12)O—C10—H10B109.5
H3NB—N3—C3120.3 (18)O—C10—H10C109.5
N2—C1—C2112.11 (12)H10A—C10—H10B109.5
N2—C1—C11121.01 (14)H10A—C10—H10C109.5
C2—C1—C11126.87 (13)H10B—C10—H10C109.5
C1—C2—H2127.1C1—C11—C12121.62 (13)
C1—C2—C3105.89 (13)C1—C11—C16119.26 (14)
H2—C2—C3127.1C12—C11—C16119.10 (14)
N1—C3—N3123.63 (13)C11—C12—H12119.9
N1—C3—C2106.28 (13)C11—C12—C13120.14 (15)
N3—C3—C2130.03 (15)H12—C12—C13119.9
N1—C4—C5121.32 (13)C12—C13—H13119.9
N1—C4—C9119.27 (12)C12—C13—C14120.28 (17)
C5—C4—C9119.38 (12)H13—C13—C14119.9
C4—C5—H5120.1C13—C14—H14120.1
C4—C5—C6119.90 (14)C13—C14—C15119.89 (15)
H5—C5—C6120.1H14—C14—C15120.1
C5—C6—H6119.8C14—C15—H15119.8
C5—C6—C7120.38 (13)C14—C15—C16120.38 (15)
H6—C6—C7119.8H15—C15—C16119.8
O—C7—C6115.73 (13)C11—C16—C15120.20 (16)
O—C7—C8124.18 (14)C11—C16—H16119.9
C6—C7—C8120.09 (13)C15—C16—H16119.9
C7—C8—H8120.4
C3—N1—N2—C10.13 (14)C10—O—C7—C85.6 (2)
C4—N1—N2—C1−179.13 (11)C5—C6—C7—O178.30 (14)
N1—N2—C1—C20.31 (15)C5—C6—C7—C8−1.9 (2)
N1—N2—C1—C11179.87 (11)O—C7—C8—C9179.71 (14)
N2—C1—C2—C3−0.62 (17)C6—C7—C8—C9−0.1 (2)
C11—C1—C2—C3179.85 (13)N1—C4—C9—C8176.33 (13)
N2—N1—C3—N3176.99 (14)C5—C4—C9—C8−1.6 (2)
N2—N1—C3—C2−0.51 (16)C7—C8—C9—C41.8 (2)
C4—N1—C3—N3−3.9 (2)N2—C1—C11—C1229.1 (2)
C4—N1—C3—C2178.65 (12)N2—C1—C11—C16−151.79 (14)
C1—C2—C3—N10.65 (16)C2—C1—C11—C12−151.35 (15)
C1—C2—C3—N3−176.62 (16)C2—C1—C11—C1627.7 (2)
N2—N1—C4—C5141.21 (14)C1—C11—C12—C13179.32 (14)
N2—N1—C4—C9−36.72 (18)C16—C11—C12—C130.3 (2)
C3—N1—C4—C5−37.9 (2)C11—C12—C13—C140.0 (3)
C3—N1—C4—C9144.17 (15)C12—C13—C14—C15−0.2 (3)
N1—C4—C5—C6−178.27 (13)C13—C14—C15—C160.1 (3)
C9—C4—C5—C6−0.3 (2)C14—C15—C16—C110.1 (3)
C4—C5—C6—C72.1 (2)C1—C11—C16—C15−179.39 (15)
C10—O—C7—C6−174.60 (16)C12—C11—C16—C15−0.3 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3NA···N2i0.89 (2)2.37 (2)3.228 (2)162.5 (16)
Symmetry code: (i) x, y−1, z.

Experimental details

Crystal data
Chemical formulaC16H15N3O
Mr265.31
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)296
a, b, c (Å)14.9638 (6), 6.3639 (2), 28.2466 (12)
V (Å3)2689.87 (18)
Z8
Radiation typeMo Kα
µ (mm−1)0.09
Crystal size (mm)0.35 × 0.35 × 0.05
Data collection
DiffractometerBruker Kappa APEXII
diffractometer
Absorption correction–
No. of measured, independent and
observed [I > 2σ(I)] reflections		11632, 3019, 2256
Rint0.031
(sin θ/λ)max (Å−1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.111, 1.02
No. of reflections3019
No. of parameters190
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.20, −0.15

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXTL (Sheldrick, 2008) and local programs.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3NA···N2i0.89 (2)2.37 (2)3.228 (2)162.5 (16)
Symmetry code: (i) x, y−1, z.
 

Acknowledgements

This work was supported by the United States Public Health Service, National Institute on Drug Abuse grants DA06284 and DA13449. We thank Professor Bob Downs, Department of Geosciences, University of Arizona, for the data collection.

References

First citationBruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationGavrin, L. K., Lee, A., Provencher, B. A., Massefski, W. W., Huhn, S. D., Ciszewski, G. M., Cole, D. C. & McKew, J. C. (2007). J. Org. Chem., 72, 1043–1046.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationJoshi, K. C., Pathak, V. N. & Garg, U. (1979). J. Heterocycl. Chem. 16, 1141–1145.  CrossRef CAS Google Scholar
 First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationMichaux, C. & Charlier, C. (2004). Mini-Rev. Med. Chem. 4, 603–615.  CrossRef CAS Google Scholar
 First citationOssipov, M. H., Lai, J., King, T., Vanderah, T. W., Malan, T. P., Hruby, V. J. & Porreca, F. (2004). J. Neurobiol. 61, 126–148.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationRaffa, R. B. (2001). J. Clin. Pharm. Ther. 26, 257–264.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals 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.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 5| May 2009| Page o1170
doi:10.1107/S1600536809015463
Follow Acta Cryst. E
Sign up for e-alerts
E-alerts
Follow Acta Cryst. on Twitter
Twitter
Follow us on facebook
Facebook
Sign up for RSS feeds
RSS