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

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ISSN: 2056-9890

(S)-4-Phenyl-2-(1,2,3,4-tetra­hydro­isoquinolin-3-yl)-1,3-thia­zole

aSchool of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban 4000, South Africa, and bSchool of Chemistry, University of KwaZulu-Natal, Durban 4000, South Africa
*Correspondence e-mail: maguireg@ukzn.ac.za

(Received 7 September 2011; accepted 6 December 2011; online 21 December 2011)

In the title compound, C18H16N2S, the N-containing ring adopts a half-chair configuration. The crystal packing features C—H⋯N contacts. There is no ππ stacking within the crystal structure.

Related literature

The title compound is a potential ligand for the asymmetric Henry reaction. For the application of these ligands as catalysts, see: Chakka et al. (2010[Chakka, S. K., Peters, B. K., Andersson, P. G., Maguire, G. E. M., Kruger, H. G. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 2295-2301.]); Kawthekar et al. (2010[Kawthekar, R. B., Chakka, S. K., Francis, V., Andersson, P. G., Kruger, H. G., Maguire, G. E. M. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 846-852.]); Peters et al. (2010[Peters, B. K., Chakka, S. K., Naicker, T., Maguire, G. E. M., Kruger, H. G., Andersson, P. G. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 679-, 687.]); Naicker et al. (2010[Naicker, T., Petzold, K., Singh, T., Arvidsson, P. I., Kruger, H. G., Maguire, G. E. M. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 2859-2867.]). For related structures, see: Naicker et al. (2011a[Naicker, T., Govender, T., Kruger, H. G. & Maguire, G. E. M. (2011a). Acta Cryst. E67, o67.],b[Naicker, T., Govender, T., Kruger, H. G. & Maguire, G. E. M. (2011b). Acta Cryst. E67, o1403.]).

[Scheme 1]

Experimental

Crystal data
  • C18H16N2S

  • Mr = 292.39

  • Trigonal, P 32

  • a = 16.223 (1) Å

  • c = 4.8130 (3) Å

  • V = 1097.0 (1) Å3

  • Z = 3

  • Mo Kα radiation

  • μ = 0.22 mm−1

  • T = 173 K

  • 0.20 × 0.10 × 0.09 mm

Data collection
  • Bruker Kappa DUO APEXII diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) Tmin = 0.958, Tmax = 0.981

  • 14735 measured reflections

  • 3676 independent reflections

  • 3205 reflections with I > 2σ(I)

  • Rint = 0.030

Refinement
  • R[F2 > 2σ(F2)] = 0.035

  • wR(F2) = 0.084

  • S = 1.03

  • 3676 reflections

  • 194 parameters

  • 1 restraint

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

  • Δρmax = 0.23 e Å−3

  • Δρmin = −0.22 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 1832 Friedel pairs

  • Flack parameter: −0.02 (6)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C11—H11⋯N1i 0.95 2.54 3.341 (3) 142
Symmetry code: (i) [-y+1, x-y+2, z-{\script{1\over 3}}].

Data collection: APEX2 (Bruker, 2006[Bruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2006[Bruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Tetrahydroisoquinoline is a core structure in various natural and pharmaceutically active compounds, displaying a broad spectrum of activity. Molecules with a C1-symmetric tetrahydroisoquinoline backbone have been studied for various catalytic reactions such as allylic alkylation (Blanc et al.,2003), Henry reactions (Kawthekar et al., 2010), asymmetric hydrogenation reactions (Chakka et al.,2010; Peters et al., 2010) and Diels-Alder reactions (Naicker et al.,2010). The title compound is one of the ligands used for asymmetric Henry reaction, its' catalytic activity is currently under investigation. The chiral carbon (C9) has been assigned an S configuration from two-dimensional NMR measurements.

In the title compound, the piperidine ring of the tetrahydroisoquinolinone unit adopts a half chair (Fig 1). This hetrocyclic ring within similar structures displays either a half chair or half boat conformation (Naicker et al. 2011a; 2011b). From the crystal structure it is evident that the N-containing six membered ring assumes a half chair conformation [Q = 0.483 (2) Å, θ = 50.1 (2)° and ϕ = 321.8 (3)°]. The torsion angle for C1—N1—C9—C10 is -171.72 (14)°. From the plain formed by the atoms C1—C2—C7—C8—C9—N1 the maximum displacement from planarity for N1 is 0.297 Å and for C9 0.331 Å (Fig. 1). This is similar to our previously reported structures which also assume half chair conformations (Naicker et al., 2011a; 2011b). The crystal packing contains C—H···N contacts of distance 3.341 (3) Å (see Fig. 2) (Table 1). There is no π-π stacking within the crystal structure.

Related literature top

The title compound is a potential ligand for the assymetric Henry reaction. For the application of these ligands as catalysts, see: Chakka et al. (2010); Kawthekar et al. (2010); Peters et al. (2010); Naicker et al. (2010). For related structures, see: Naicker et al. (2011a,b).

Experimental top

The N-protected thiazole (3 mmol) was dissolved in THF (15 ml), to this 12 M HCl (15 ml) was added slowly and the reaction mixture was stirred at room temperature for 2 h. THF was evaporated under vacuum. The reaction was monitored by TLC using EtOAc/Hexane (20:80, Rf = 0.5). The reaction mixture was slowly poured into aqueous saturated NaHCO3 solution, the mixture was then extracted with CH2Cl2 (3 x 30 ml). The combined organic layer was dried over MgSO4. The solvent was evaporated under reduced pressure, the residue was purified by column chromatography on silica gel (deactivated with 5% Et3N) with Et3N/EtOAc/Hexane (5/8/100) as the eluent to afford the thiazole as a yellow solid (0.27 g, yield 95%). M.p. = 357–360 K.

Recrystallization from tetrahydrofuran at room temperature afforded colourless crystals suitable for X-ray analysis.

Refinement top

All non-hydrogen atoms were refined anisotropically. All hydrogen atoms, except H1N, were positioned geometrically with C—H distances ranging from 0.95 Å to 1.00 Å and refined as riding on their parent atoms with Uiso (H) = 1.2 - 1.5 Ueq (C).

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 40% probability level. The hydrogen atoms have been omitted for clarity.
[Figure 2] Fig. 2. CH···N interactions along the b axis.
(S)-4-Phenyl-2-(1,2,3,4-tetrahydroisoquinolin-3-yl)-1,3-thiazole top
Crystal data top
C18H16N2SDx = 1.328 Mg m3
Mr = 292.39Mo Kα radiation, λ = 0.71073 Å
Trigonal, P32Cell parameters from 14735 reflections
Hall symbol: P 32θ = 2.5–28.4°
a = 16.223 (1) ŵ = 0.22 mm1
c = 4.8130 (3) ÅT = 173 K
V = 1097.0 (1) Å3Needle, yellow
Z = 30.20 × 0.10 × 0.09 mm
F(000) = 462
Data collection top
Bruker Kappa DUO APEXII
diffractometer
3676 independent reflections
Radiation source: fine-focus sealed tube3205 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
0.5° ϕ scans and ω scansθmax = 28.4°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008)
h = 2121
Tmin = 0.958, Tmax = 0.981k = 2121
14735 measured reflectionsl = 66
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.035H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.084 w = 1/[σ2(Fo2) + (0.0433P)2 + 0.1159P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
3676 reflectionsΔρmax = 0.23 e Å3
194 parametersΔρmin = 0.22 e Å3
1 restraintAbsolute structure: Flack (1983), 1832 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.02 (6)
Crystal data top
C18H16N2SZ = 3
Mr = 292.39Mo Kα radiation
Trigonal, P32µ = 0.22 mm1
a = 16.223 (1) ÅT = 173 K
c = 4.8130 (3) Å0.20 × 0.10 × 0.09 mm
V = 1097.0 (1) Å3
Data collection top
Bruker Kappa DUO APEXII
diffractometer
3676 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008)
3205 reflections with I > 2σ(I)
Tmin = 0.958, Tmax = 0.981Rint = 0.030
14735 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.035H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.084Δρmax = 0.23 e Å3
S = 1.03Δρmin = 0.22 e Å3
3676 reflectionsAbsolute structure: Flack (1983), 1832 Friedel pairs
194 parametersAbsolute structure parameter: 0.02 (6)
1 restraint
Special details top

Experimental. Half sphere of data collected using the Bruker SAINT software package. Crystal to detector distance = 30 mm; combination of ϕ and ω scans of 0.5°, 60 s per °, 2 iterations.

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
S10.00297 (4)0.88075 (3)0.01223 (14)0.04813 (15)
N10.22129 (10)0.70793 (10)0.1094 (3)0.0316 (3)
H1N0.2357 (14)0.6647 (15)0.032 (4)0.036 (5)*
N20.01656 (9)0.71580 (9)0.0576 (3)0.0287 (3)
C10.30267 (13)0.67560 (13)0.2960 (4)0.0359 (4)
H1A0.36030.65690.18250.043*
H1B0.29260.72980.41420.043*
C20.32126 (11)0.59286 (11)0.4831 (4)0.0287 (3)
C30.40599 (13)0.54595 (12)0.6353 (4)0.0359 (4)
H30.45200.56550.61740.043*
C40.42359 (13)0.47165 (13)0.8110 (4)0.0393 (4)
H40.48160.44020.91220.047*
C50.35671 (14)0.44283 (12)0.8399 (4)0.0385 (4)
H50.36880.39150.95990.046*
C60.27209 (13)0.48947 (12)0.6927 (4)0.0323 (4)
H60.22600.47020.71450.039*
C70.25347 (12)0.56434 (11)0.5129 (3)0.0272 (3)
C80.16028 (11)0.61485 (12)0.3565 (4)0.0290 (3)
H8A0.16300.57590.19450.035*
H8B0.10800.62220.47910.035*
C90.13971 (12)0.71258 (12)0.2570 (4)0.0307 (4)
H90.12680.75380.42440.037*
C100.05355 (12)0.75944 (11)0.0730 (4)0.0300 (3)
C110.08088 (13)0.87065 (13)0.2040 (4)0.0388 (4)
H110.13140.92220.30070.047*
C120.06065 (11)0.77863 (11)0.2186 (4)0.0297 (3)
C130.11195 (12)0.74191 (12)0.3839 (4)0.0304 (4)
C140.08499 (13)0.64602 (13)0.3768 (4)0.0362 (4)
H140.03360.60360.26160.043*
C150.13257 (14)0.61174 (14)0.5369 (5)0.0433 (4)
H150.11350.54600.53040.052*
C160.20739 (14)0.67241 (16)0.7052 (5)0.0468 (5)
H160.23980.64890.81500.056*
C170.23454 (16)0.76791 (16)0.7122 (5)0.0506 (5)
H170.28600.81020.82750.061*
C180.18785 (15)0.80224 (15)0.5542 (4)0.0435 (5)
H180.20760.86810.56110.052*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0455 (3)0.0274 (2)0.0703 (3)0.0174 (2)0.0198 (3)0.0061 (2)
N10.0336 (7)0.0316 (7)0.0329 (8)0.0188 (6)0.0027 (6)0.0008 (6)
N20.0263 (7)0.0257 (7)0.0299 (7)0.0099 (6)0.0002 (6)0.0010 (6)
C10.0344 (9)0.0346 (9)0.0433 (10)0.0208 (8)0.0042 (8)0.0016 (8)
C20.0280 (8)0.0268 (8)0.0284 (8)0.0116 (7)0.0020 (7)0.0058 (7)
C30.0294 (8)0.0337 (9)0.0423 (10)0.0141 (7)0.0030 (8)0.0054 (8)
C40.0344 (9)0.0319 (9)0.0413 (10)0.0088 (7)0.0103 (8)0.0014 (8)
C50.0463 (11)0.0280 (8)0.0348 (10)0.0138 (8)0.0055 (8)0.0025 (7)
C60.0372 (9)0.0299 (8)0.0300 (9)0.0169 (7)0.0014 (7)0.0031 (7)
C70.0291 (8)0.0255 (7)0.0243 (8)0.0117 (6)0.0010 (6)0.0058 (6)
C80.0303 (8)0.0295 (8)0.0290 (8)0.0163 (7)0.0008 (7)0.0004 (7)
C90.0321 (8)0.0278 (8)0.0314 (9)0.0143 (7)0.0012 (7)0.0026 (7)
C100.0293 (8)0.0241 (8)0.0332 (9)0.0106 (6)0.0004 (7)0.0027 (7)
C110.0307 (9)0.0323 (9)0.0492 (11)0.0127 (7)0.0090 (8)0.0062 (8)
C120.0246 (7)0.0282 (8)0.0324 (9)0.0102 (6)0.0018 (7)0.0026 (7)
C130.0259 (7)0.0331 (8)0.0292 (9)0.0126 (7)0.0028 (7)0.0006 (7)
C140.0316 (9)0.0334 (9)0.0422 (10)0.0152 (7)0.0045 (8)0.0038 (8)
C150.0432 (10)0.0385 (10)0.0516 (12)0.0230 (9)0.0000 (9)0.0032 (9)
C160.0408 (10)0.0552 (12)0.0475 (12)0.0263 (10)0.0019 (9)0.0101 (10)
C170.0432 (11)0.0513 (12)0.0493 (13)0.0177 (10)0.0186 (10)0.0060 (10)
C180.0424 (10)0.0369 (10)0.0456 (11)0.0157 (8)0.0133 (9)0.0078 (9)
Geometric parameters (Å, º) top
S1—C111.707 (2)C7—C81.512 (2)
S1—C101.7306 (17)C8—C91.525 (2)
N1—C11.460 (2)C8—H8A0.9900
N1—C91.470 (2)C8—H8B0.9900
N1—H1N0.92 (2)C9—C101.501 (2)
N2—C101.297 (2)C9—H91.0000
N2—C121.390 (2)C11—C121.361 (2)
C1—C21.516 (2)C11—H110.9500
C1—H1A0.9900C12—C131.475 (2)
C1—H1B0.9900C13—C141.390 (2)
C2—C71.397 (2)C13—C181.393 (3)
C2—C31.400 (2)C14—C151.389 (3)
C3—C41.380 (3)C14—H140.9500
C3—H30.9500C15—C161.380 (3)
C4—C51.387 (3)C15—H150.9500
C4—H40.9500C16—C171.383 (3)
C5—C61.386 (3)C16—H160.9500
C5—H50.9500C17—C181.372 (3)
C6—C71.396 (2)C17—H170.9500
C6—H60.9500C18—H180.9500
C11—S1—C1089.46 (9)H8A—C8—H8B108.0
C1—N1—C9110.51 (13)N1—C9—C10109.12 (13)
C1—N1—H1N110.0 (13)N1—C9—C8112.02 (13)
C9—N1—H1N106.0 (13)C10—C9—C8112.09 (13)
C10—N2—C12111.30 (14)N1—C9—H9107.8
N1—C1—C2115.29 (14)C10—C9—H9107.8
N1—C1—H1A108.5C8—C9—H9107.8
C2—C1—H1A108.5N2—C10—C9125.27 (15)
N1—C1—H1B108.5N2—C10—S1114.34 (13)
C2—C1—H1B108.5C9—C10—S1120.36 (12)
H1A—C1—H1B107.5C12—C11—S1110.66 (14)
C7—C2—C3119.19 (16)C12—C11—H11124.7
C7—C2—C1120.86 (14)S1—C11—H11124.7
C3—C2—C1119.92 (15)C11—C12—N2114.22 (16)
C4—C3—C2120.90 (17)C11—C12—C13126.56 (16)
C4—C3—H3119.5N2—C12—C13119.21 (14)
C2—C3—H3119.5C14—C13—C18118.28 (17)
C3—C4—C5120.06 (17)C14—C13—C12120.88 (16)
C3—C4—H4120.0C18—C13—C12120.83 (16)
C5—C4—H4120.0C15—C14—C13120.51 (17)
C6—C5—C4119.54 (17)C15—C14—H14119.7
C6—C5—H5120.2C13—C14—H14119.7
C4—C5—H5120.2C16—C15—C14120.46 (19)
C5—C6—C7121.10 (17)C16—C15—H15119.8
C5—C6—H6119.5C14—C15—H15119.8
C7—C6—H6119.5C15—C16—C17119.16 (19)
C6—C7—C2119.21 (15)C15—C16—H16120.4
C6—C7—C8120.20 (15)C17—C16—H16120.4
C2—C7—C8120.58 (15)C18—C17—C16120.65 (19)
C7—C8—C9111.08 (13)C18—C17—H17119.7
C7—C8—H8A109.4C16—C17—H17119.7
C9—C8—H8A109.4C17—C18—C13120.93 (19)
C7—C8—H8B109.4C17—C18—H18119.5
C9—C8—H8B109.4C13—C18—H18119.5
C9—N1—C1—C243.4 (2)C8—C9—C10—N219.7 (2)
N1—C1—C2—C712.8 (2)N1—C9—C10—S173.07 (17)
N1—C1—C2—C3169.22 (16)C8—C9—C10—S1162.25 (13)
C7—C2—C3—C40.7 (3)C11—S1—C10—N20.18 (15)
C1—C2—C3—C4178.73 (16)C11—S1—C10—C9178.05 (15)
C2—C3—C4—C50.3 (3)C10—S1—C11—C120.02 (16)
C3—C4—C5—C60.4 (3)S1—C11—C12—N20.2 (2)
C4—C5—C6—C70.8 (3)S1—C11—C12—C13179.92 (14)
C5—C6—C7—C20.4 (3)C10—N2—C12—C110.3 (2)
C5—C6—C7—C8179.40 (16)C10—N2—C12—C13179.78 (15)
C3—C2—C7—C60.3 (2)C11—C12—C13—C14178.82 (19)
C1—C2—C7—C6178.32 (16)N2—C12—C13—C141.0 (2)
C3—C2—C7—C8178.67 (15)C11—C12—C13—C182.1 (3)
C1—C2—C7—C80.6 (2)N2—C12—C13—C18178.05 (16)
C6—C7—C8—C9160.07 (15)C18—C13—C14—C150.3 (3)
C2—C7—C8—C918.9 (2)C12—C13—C14—C15178.84 (17)
C1—N1—C9—C10171.71 (14)C13—C14—C15—C160.0 (3)
C1—N1—C9—C863.57 (18)C14—C15—C16—C170.1 (3)
C7—C8—C9—N150.29 (18)C15—C16—C17—C180.0 (3)
C7—C8—C9—C10173.34 (13)C16—C17—C18—C130.2 (3)
C12—N2—C10—C9177.80 (16)C14—C13—C18—C170.4 (3)
C12—N2—C10—S10.32 (18)C12—C13—C18—C17178.8 (2)
N1—C9—C10—N2104.95 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···N1i0.952.543.341 (3)142
Symmetry code: (i) y+1, xy+2, z1/3.

Experimental details

Crystal data
Chemical formulaC18H16N2S
Mr292.39
Crystal system, space groupTrigonal, P32
Temperature (K)173
a, c (Å)16.223 (1), 4.8130 (3)
V3)1097.0 (1)
Z3
Radiation typeMo Kα
µ (mm1)0.22
Crystal size (mm)0.20 × 0.10 × 0.09
Data collection
DiffractometerBruker Kappa DUO APEXII
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2008)
Tmin, Tmax0.958, 0.981
No. of measured, independent and
observed [I > 2σ(I)] reflections
14735, 3676, 3205
Rint0.030
(sin θ/λ)max1)0.669
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.084, 1.03
No. of reflections3676
No. of parameters194
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.23, 0.22
Absolute structureFlack (1983), 1832 Friedel pairs
Absolute structure parameter0.02 (6)

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···N1i0.952.543.341 (3)142
Symmetry code: (i) y+1, xy+2, z1/3.
 

Acknowledgements

The authors thank Dr Hong Su of the University of Capetown for the data collection and structure refinement.

References

First citationBruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationChakka, S. K., Peters, B. K., Andersson, P. G., Maguire, G. E. M., Kruger, H. G. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 2295–2301.  Web of Science CrossRef CAS
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals
First citationKawthekar, R. B., Chakka, S. K., Francis, V., Andersson, P. G., Kruger, H. G., Maguire, G. E. M. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 846–852.  Web of Science CrossRef CAS
First citationNaicker, T., Govender, T., Kruger, H. G. & Maguire, G. E. M. (2011a). Acta Cryst. E67, o67.  Web of Science CrossRef IUCr Journals
First citationNaicker, T., Govender, T., Kruger, H. G. & Maguire, G. E. M. (2011b). Acta Cryst. E67, o1403.  Web of Science CSD CrossRef IUCr Journals
First citationNaicker, T., Petzold, K., Singh, T., Arvidsson, P. I., Kruger, H. G., Maguire, G. E. M. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 2859–2867.  Web of Science CrossRef CAS
First citationPeters, B. K., Chakka, S. K., Naicker, T., Maguire, G. E. M., Kruger, H. G., Andersson, P. G. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 679–, 687.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals

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