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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 67| Part 11| November 2011| Page o3005
doi:10.1107/S1600536811042486

(E)-2-(2-Methyl­cyclo­hexyl­­idene)hydrazinecarbo­thio­amide

Justin W. Hicks,a Alan J. Lough,b* Alan A. Wilsona and Neil Vasdeva

aPET Centre, Centre for Addiction and Mental Health, and Institute of Medical Science, University of Toronto, 250 College Street, Toronto, Ontario, Canada M5T 1R8, and bDepartment of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario, Canada M5S 3H6
*Correspondence e-mail: alough@chem.utoronto.ca

(Received 11 October 2011; accepted 13 October 2011; online 22 October 2011)

In the crystal of the title compound, C8H15N3S, mol­ecules are linked by N—H⋯S hydrogen bonds, forming chains along [1[\overline{1}]0]. An intra­molecular N—H⋯N hydrogen bond is also present.

Related literature

The title compound, C8H15N3S, is a key inter­mediate for the preparation of hydrazinyl-5-aryl­thia­zole-based monoamine oxidase B (MAO-B) inhibitors. For the synthesis of hydrazinyl-5-aryl­thia­zoles and their MAO-B inhibitory activity, see: Chimenti et al. (2008[Chimenti, F., Maccioni, E., Secci, D., Bolasco, A., Chimenti, P., Carradori, S., Alcaro, S., Ortuso, F., Yanez, M., Orallo, F., Cirilli, R., Ferretti, R. & La Torre, F. (2008). J. Med. Chem. 51, 4878-4880.], 2010[Chimenti, F., Secci, D., Bolasco, A., Chimenti, P., Granese, A., Carradori, S., Yanez, M., Orallo, F., Sanna, M. L., Gallinella, B. & Cirilli, R. (2010). J. Med. Chem. 53, 6516-6520.]). For background on our inter­est in radiolabelled mol­ecules targeting MAO-B, see: Vasdev et al. (2011a[Vasdev, N., Sadovski, O., Moran, M. D., Parkes, J., Meyer, J. H., Houle, S. & Wilson, A. A. (2011a). Nucl. Med. Biol. 38, 933-943.],b[Vasdev, N., Sadovski, O., Garcia, A., Dollé, F., Meyer, J. H., Houle, S. & Wilson, A. A. (2011b). J. Labelled Compd Radiopharm. pp. 678-680.]). For the preparation of 18F-labelled potassium cryptand fluoride, see: Vasdev et al. (2009[Vasdev, N., Choi, J., van Oosten, E. M., Nitz, M., McLaurin, J., Vines, D. C., Houle, S., Reilly, R. M. & Wilson, A. A. (2009). Chem. Commun. pp. 5527-5529.]).

[Scheme 1]

Experimental

Crystal data

  • C8H15N3S

  • Mr = 185.29

  • Triclinic, [P \overline 1]

  • a = 6.0261 (5) Å

  • b = 8.0655 (4) Å

  • c = 10.9129 (9) Å

  • α = 83.904 (5)°

  • β = 89.386 (4)°

  • γ = 68.416 (4)°

  • V = 490.19 (6) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.28 mm−1

  • T = 150 K

  • 0.20 × 0.14 × 0.04 mm
Data collection

  • Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (SORTAV; Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.]) Tmin = 0.710, Tmax = 1.060

  • 5938 measured reflections

  • 2184 independent reflections

  • 1698 reflections with I > 2σ(I)

  • Rint = 0.077
Refinement

  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.122

  • S = 1.05

  • 2184 reflections

  • 122 parameters

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

  • Δρmax = 0.26 e Å−3

  • Δρmin = −0.25 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
N2—H1N⋯S1i 0.88 (3) 2.61 (3) 3.4645 (19) 162 (2)
N3—H3N⋯S1ii 0.88 (2) 2.52 (2) 3.3954 (19) 170.9 (19)
N3—H2N⋯N1 0.81 (3) 2.28 (2) 2.601 (2) 104.6 (19)
Symmetry codes: (i) -x, -y+1, -z; (ii) -x+1, -y, -z.

Data collection: COLLECT (Nonius, 2002[Nonius (2002). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997[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.]); data reduction: DENZO-SMN; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811042486/pv2460sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811042486/pv2460Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811042486/pv2460Isup3.cml

checkCIF report


Comment top

(E)-2-(2-Methylcyclohexylidene)hydrazinecarbothioamide is an intermediate towards the preparation of hydrazinyl-5-arylthiazoles which are curerntly under exploration as a new class of inhibitors of the enzyme monoamine oxidase B (Chimenti et al. 2010). Our interest in this class of compounds is to prepare a radiotracer for imaging MAO-B in the central nervous system with positron emission tomography (PET). Chimenti et al. (2010) reported the synthesis of (E)-2-(2-(2-methylcyclohexylidene)hydrazinyl)-5-(4-nitrophenyl)thiazole, and (E)-2-(2-(2-methylcyclohexylidene)hydrazinyl)-5-(4-fluorophenyl)thiazole which demonstrated high affinity for MAO-B (Ki > 10 nM). We have attempted to use the 4-nitrophenyl thiazole derivative as a precursor for radiofluorination with the positron emitting isotope fluorine-18 (t1/2 = 109.7 min) to prepare [18F]-(E)-2-(2-(2- methylcyclohexylidene)hydrazinyl)-5-(4-fluorophenyl)thiazole. Although initial attempts to achieve this goal have not been successful due to degradation of the precursor under basic conditions, we continue to investigate the application of thiazoles as an activating group for aromatic radiofluorination.

The molecular structure of the title compound is shown in Fig. 1. In the crystal, molecules are linked by N—H···S hydrogen bonds to form chains along [110] (see Fig. 2). An intramolecular N—H···N hydrogen bond is also present.

Related literature top

The title compound, C8H15N3S, is a key intermediate for the preparation of hydrazinyl-5-arylthiazole-based monoamine oxidase B (MAO-B) inhibitors. For the synthesis of hydrazinyl-5-arylthiazoles and their MAO-B inhibitory activity, see: Chimenti et al. (2008, 2010). For background on our interest in radiolabelled molecules targeting MAO-B, see: Vasdev et al. (2011a,b). For the preparation of 18F-labelled potassium cryptand fluoride, see: Vasdev et al. (2009).

Experimental top

Synthesis

The title compound, C8H15N3S, was obtained by stirring equimolar amounts (10 mmol) of racemic 2-methylcyclohexanone and thiosemicarbazide with a catalytic amount of acetic acid (ca 350 µL) in 2-propanol (100 ml) for 16 h at room temperature. A white precipitate resulted and was collected by vacuum filtration and washed with cold 2-propanol (3 x 20 ml). This solid was then dissolved in chloroform (20 ml) and the insoluble unreacted thiosemicarbazide was removed by vacuum filtration. The solvent was removed from the filtrate by rotary evaporation and C8H15N3S was obtained as a white solid in 98% yield. X-ray quality crystals were obtained by slow evaporation of a solution of the title compound in 1:1:2 chloroform/acetonitrile/acetone. m.p. = 420 - 421 K.

Attempted Radiosynthesis

Dry 18F-labeled potassium cryptand fluoride ([K222][18F]; 760 µCi) was prepared as previously described (Vasdev et al., 2009). A solution of 2-(2-cyclohexylidenehydrazinyl)-4-(4-nitrophenyl)thiazole in anhydrous CH3CN (9.5 mM, 1 ml) was added to the glass test tube and the solution turned a dark purple. The reaction was stirred at room temperature for 10 minutes, then an aliquot was quenched in HPLC buffer to monitor the progress of the reaction by analytical HPLC. As no reaction occurred, the mixture was then heated to 333 K and 363 K in an oil bath for 10 minutes, respectively, with still no reaction occurring. Analytical HPLC was performed using a perfluorophenyl column (Thermo Scientific Fluophase PFP, 150 x 10 mm, 5 µm) eluted with 70:30 CH3OH:H2O + 0.1 N ammonium formate using a flow of 5 ml min-1. Authentic 2-(2-cyclohexylidenehydrazinyl)-4-(4-fluorophenyl)thiazole (tR = 12.5 min) was used as a standard.

A second reaction under microwave heating (60 W) was also attempted using dimethylsulfoxide (DMSO) as the solvent. The reaction again turned dark purple with the addition of the precursor as a DMSO solution (9.5 mM, 1 ml) to the dry [K222][18F] containing glass test tube. After heating to 393 K for 5 minutes with no reaction occurring, the temperature was increased to 453 K for 15 minutes. At this point, there was no precursor remaining intact, as determined by analytical HPLC. Proton NMR spectroscopy revealed that the hydrazinic proton is removed under basic conditions.

Refinement top

H atoms bonded to C atoms were placed in calculated positions with C—H = 0.98 - 1.00Å and were included in the refinement with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(Cmethyl). H atoms bonded to N atoms were refined independently with isotropic displacement parameters.

Computing details top

Data collection: COLLECT (Nonius, 2002); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure with ellipsoids drawn at the 30% probabilty level.
[Figure 2] Fig. 2. Part of the crystal structure with hydrogen bonds drawn as dashed lines. Only H atoms involved in hydrogen bonds are shown.
(E)-2-(2-Methylcyclohexylidene)hydrazinecarbothioamide top
Crystal data top
C8H15N3SZ = 2
Mr = 185.29F(000) = 200
Triclinic, P1Dx = 1.255 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.0261 (5) ÅCell parameters from 5938 reflections
b = 8.0655 (4) Åθ = 2.6–27.5°
c = 10.9129 (9) ŵ = 0.28 mm−1
α = 83.904 (5)°T = 150 K
β = 89.386 (4)°Plate, colourless
γ = 68.416 (4)°0.20 × 0.14 × 0.04 mm
V = 490.19 (6) Å3
Data collection top
Nonius KappaCCD
diffractometer		2184 independent reflections
Radiation source: fine-focus sealed tube1698 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.077
Detector resolution: 9 pixels mm-1θmax = 27.6°, θmin = 2.7°
ϕ scans and ω scans with κ offsetsh = −7→7
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)		k = −10→10
Tmin = 0.710, Tmax = 1.060l = −13→14
5938 measured reflections
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)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122H atoms treated by a mixture of independent and constrained refinement
S = 1.05 w = 1/[σ2(Fo2) + (0.0454P)2 + 0.1232P]
where P = (Fo2 + 2Fc2)/3
2184 reflections(Δ/σ)max < 0.001
122 parametersΔρmax = 0.26 e Å−3
0 restraintsΔρmin = −0.25 e Å−3
Crystal data top
C8H15N3Sγ = 68.416 (4)°
Mr = 185.29V = 490.19 (6) Å3
Triclinic, P1Z = 2
a = 6.0261 (5) ÅMo Kα radiation
b = 8.0655 (4) ŵ = 0.28 mm−1
c = 10.9129 (9) ÅT = 150 K
α = 83.904 (5)°0.20 × 0.14 × 0.04 mm
β = 89.386 (4)°
Data collection top
Nonius KappaCCD
diffractometer		2184 independent reflections
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)		1698 reflections with I > 2σ(I)
Tmin = 0.710, Tmax = 1.060Rint = 0.077
5938 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.122H atoms treated by a mixture of independent and constrained refinement
S = 1.05Δρmax = 0.26 e Å−3
2184 reflectionsΔρmin = −0.25 e Å−3
122 parameters
Special details top

Experimental. 1H NMR (CDCl3, 400 MHz) δ p.p.m. 8.83 (br s, 1H), 7.25 (br s, 1H), 6.48 (br s, 1H), 2.66 (m, 1H), 2.29 - 2.40 (m, 1H), 1.84 - 2.00 (m, 3H), 1.75 - 1.83 (m, 1H), 1.41 - 1.66 (m, 2H), 1.23 - 1.36 (m, 1H), 1.10 (d, J= 6.6 Hz, 3H). HRMS (ESI) m/z calcd for C8H16N3S, 186.1059; found 186.1064 (M++H).

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
S10.17188 (9)0.22748 (6)0.01937 (5)0.03606 (19)
N10.5032 (3)0.4731 (2)0.19337 (16)0.0335 (4)
H1N0.185 (5)0.522 (3)0.104 (2)0.051 (7)*
N20.3306 (3)0.4439 (2)0.12560 (17)0.0336 (4)
N30.6066 (3)0.1654 (2)0.10779 (19)0.0428 (5)
H2N0.708 (4)0.195 (3)0.137 (2)0.047 (7)*
H3N0.649 (4)0.061 (3)0.078 (2)0.039 (6)*
C10.4559 (4)0.6253 (2)0.23460 (19)0.0334 (5)
C20.6541 (4)0.6475 (3)0.3062 (2)0.0370 (5)
H2A0.70740.73440.25370.044*
C30.5603 (4)0.7327 (3)0.4246 (2)0.0437 (5)
H3A0.51900.64580.48220.052*
H3B0.68830.75930.46460.052*
C40.3419 (4)0.9048 (3)0.4007 (2)0.0476 (6)
H4A0.28490.95240.47990.057*
H4B0.38530.99590.34870.057*
C50.1440 (4)0.8698 (3)0.3362 (2)0.0456 (6)
H5A0.00660.98420.31770.055*
H5B0.08990.78800.39190.055*
C60.2269 (4)0.7867 (3)0.2168 (2)0.0407 (5)
H6A0.10090.75090.18370.049*
H6B0.25040.87780.15530.049*
C70.8715 (4)0.4756 (3)0.3314 (2)0.0450 (6)
H7A0.93050.42860.25320.067*
H7B0.82750.38660.38370.067*
H7C0.99680.50040.37350.067*
C80.3858 (3)0.2802 (2)0.08743 (18)0.0311 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0358 (3)0.0288 (3)0.0448 (4)−0.0112 (2)−0.0042 (2)−0.0115 (2)
N10.0343 (9)0.0373 (9)0.0338 (10)−0.0170 (7)0.0000 (8)−0.0105 (7)
N20.0311 (9)0.0303 (8)0.0405 (11)−0.0104 (7)−0.0030 (8)−0.0120 (7)
N30.0352 (10)0.0337 (9)0.0588 (14)−0.0073 (8)−0.0075 (9)−0.0202 (9)
C10.0381 (11)0.0348 (10)0.0306 (11)−0.0162 (9)0.0041 (9)−0.0089 (8)
C20.0385 (12)0.0423 (11)0.0371 (12)−0.0210 (9)0.0026 (10)−0.0116 (9)
C30.0464 (13)0.0503 (12)0.0424 (14)−0.0240 (10)0.0000 (11)−0.0173 (10)
C40.0531 (14)0.0452 (12)0.0505 (15)−0.0199 (11)0.0035 (12)−0.0254 (11)
C50.0446 (13)0.0413 (11)0.0513 (15)−0.0126 (10)0.0001 (11)−0.0190 (10)
C60.0478 (13)0.0330 (10)0.0422 (13)−0.0137 (9)−0.0056 (10)−0.0116 (9)
C70.0378 (12)0.0528 (13)0.0481 (14)−0.0185 (10)0.0013 (10)−0.0155 (11)
C80.0344 (11)0.0291 (9)0.0309 (11)−0.0115 (8)0.0031 (9)−0.0091 (8)
Geometric parameters (Å, º) top
S1—C81.698 (2)C3—H3A0.9900
N1—C11.284 (2)C3—H3B0.9900
N1—N21.385 (2)C4—C51.518 (3)
N2—C81.348 (2)C4—H4A0.9900
N2—H1N0.88 (3)C4—H4B0.9900
N3—C81.317 (3)C5—C61.523 (3)
N3—H2N0.81 (3)C5—H5A0.9900
N3—H3N0.88 (2)C5—H5B0.9900
C1—C61.506 (3)C6—H6A0.9900
C1—C21.508 (3)C6—H6B0.9900
C2—C71.518 (3)C7—H7A0.9800
C2—C31.532 (3)C7—H7B0.9800
C2—H2A1.0000C7—H7C0.9800
C3—C41.521 (3)
C1—N1—N2119.69 (16)C5—C4—H4B109.6
C8—N2—N1117.61 (16)C3—C4—H4B109.6
C8—N2—H1N115.7 (16)H4A—C4—H4B108.1
N1—N2—H1N126.7 (16)C4—C5—C6111.68 (19)
C8—N3—H2N121.1 (17)C4—C5—H5A109.3
C8—N3—H3N118.9 (15)C6—C5—H5A109.3
H2N—N3—H3N119 (2)C4—C5—H5B109.3
N1—C1—C6127.45 (18)C6—C5—H5B109.3
N1—C1—C2116.52 (17)H5A—C5—H5B107.9
C6—C1—C2116.01 (16)C1—C6—C5112.49 (18)
C1—C2—C7113.51 (16)C1—C6—H6A109.1
C1—C2—C3110.67 (17)C5—C6—H6A109.1
C7—C2—C3112.02 (19)C1—C6—H6B109.1
C1—C2—H2A106.7C5—C6—H6B109.1
C7—C2—H2A106.7H6A—C6—H6B107.8
C3—C2—H2A106.7C2—C7—H7A109.5
C4—C3—C2112.57 (19)C2—C7—H7B109.5
C4—C3—H3A109.1H7A—C7—H7B109.5
C2—C3—H3A109.1C2—C7—H7C109.5
C4—C3—H3B109.1H7A—C7—H7C109.5
C2—C3—H3B109.1H7B—C7—H7C109.5
H3A—C3—H3B107.8N3—C8—N2117.45 (18)
C5—C4—C3110.46 (16)N3—C8—S1122.61 (15)
C5—C4—H4A109.6N2—C8—S1119.92 (15)
C3—C4—H4A109.6
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H1N···S1i0.88 (3)2.61 (3)3.4645 (19)162 (2)
N3—H3N···S1ii0.88 (2)2.52 (2)3.3954 (19)170.9 (19)
N3—H2N···N10.81 (3)2.28 (2)2.601 (2)104.6 (19)
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y, −z.

Experimental details

Crystal data
Chemical formulaC8H15N3S
Mr185.29
Crystal system, space groupTriclinic, P1
Temperature (K)150
a, b, c (Å)6.0261 (5), 8.0655 (4), 10.9129 (9)
α, β, γ (°)83.904 (5), 89.386 (4), 68.416 (4)
V (Å3)490.19 (6)
Z2
Radiation typeMo Kα
µ (mm−1)0.28
Crystal size (mm)0.20 × 0.14 × 0.04
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(SORTAV; Blessing, 1995)
Tmin, Tmax0.710, 1.060
No. of measured, independent and
observed [I > 2σ(I)] reflections		5938, 2184, 1698
Rint0.077
(sin θ/λ)max (Å−1)0.651
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.122, 1.05
No. of reflections2184
No. of parameters122
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.26, −0.25

Computer programs: COLLECT (Nonius, 2002), DENZO-SMN (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), SHELXTL (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H1N···S1i0.88 (3)2.61 (3)3.4645 (19)162 (2)
N3—H3N···S1ii0.88 (2)2.52 (2)3.3954 (19)170.9 (19)
N3—H2N···N10.81 (3)2.28 (2)2.601 (2)104.6 (19)
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y, −z.
 

Acknowledgements

Funding was provided by the Ontario Ministry for Research and Innovation (Early Researcher Award to Dr Neil Vasdev).

References

First citationAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.  CrossRef Web of Science IUCr Journals Google Scholar
 First citationBlessing, R. H. (1995). Acta Cryst. A51, 33–38.  CrossRef CAS Web of Science IUCr Journals Google Scholar
 First citationChimenti, F., Maccioni, E., Secci, D., Bolasco, A., Chimenti, P., Carradori, S., Alcaro, S., Ortuso, F., Yanez, M., Orallo, F., Cirilli, R., Ferretti, R. & La Torre, F. (2008). J. Med. Chem. 51, 4878–4880.  Web of Science CSD CrossRef Google Scholar
 First citationChimenti, F., Secci, D., Bolasco, A., Chimenti, P., Granese, A., Carradori, S., Yanez, M., Orallo, F., Sanna, M. L., Gallinella, B. & Cirilli, R. (2010). J. Med. Chem. 53, 6516–6520.  Web of Science CrossRef CAS PubMed Google Scholar
 First citationNonius (2002). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
 First citationOtwinowski, 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
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationVasdev, N., Choi, J., van Oosten, E. M., Nitz, M., McLaurin, J., Vines, D. C., Houle, S., Reilly, R. M. & Wilson, A. A. (2009). Chem. Commun. pp. 5527–5529.  Web of Science CrossRef Google Scholar
 First citationVasdev, N., Sadovski, O., Garcia, A., Dollé, F., Meyer, J. H., Houle, S. & Wilson, A. A. (2011b). J. Labelled Compd Radiopharm. pp. 678–680.  Web of Science CrossRef Google Scholar
 First citationVasdev, N., Sadovski, O., Moran, M. D., Parkes, J., Meyer, J. H., Houle, S. & Wilson, A. A. (2011a). Nucl. Med. Biol. 38, 933–943.  Web of Science CSD CrossRef CAS PubMed Google Scholar

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ISSN: 2056-9890
Volume 67| Part 11| November 2011| Page o3005
doi:10.1107/S1600536811042486
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