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

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ISSN: 2056-9890

7-Amino-4-hy­dr­oxy-4-tri­fluoro­methyl-3,4-di­hydro­quinolin-2(1H)-one

aKey Laboratory of Fine Chemical Engineering, Changzhou University, Changzhou 213164, Jiangsu, People's Republic of China
*Correspondence e-mail: xht@cczu.edu.cn

(Received 27 July 2011; accepted 31 August 2011; online 14 September 2011)

The title compound, C10H9F3N2O2, was prepared by the reaction of m-phenyl­enediamine and ethyl 4,4,4-trifluoro­acetoacetate. In the crystal, inter­molecular C—H⋯ F, N—H⋯F, O—H⋯N and N—H⋯O inter­actions contribute to the crystal packing.

Related literature

For general background to quinolino­nes, see: Chilin et al. (1991[Chilin, A., Rodighiero, P., Pastorini, G. & Guiotto, A. (1991). J. Org. Chem. 56, 980-983.]); Oeveren et al. (2006[Oeveren, A. V., Motamedi, M., Mani, N. S., Marschke, K. B., Lopez, F. J., Schrader, W. T., Negro-Vilar, A. & Zhi, L. (2006). J. Med. Chem. 49, 6143-6146.]). For related structures, see: Oeveren et al. (2007[Oeveren, A. V., Pio, B. A., Tegley, C. M., Higuchi, R. I., Wu, M., Jones, T. K., Marschke, K. B., Negro-Vilar, A. & Zhi, L. (2007). Bioorg. Med. Chem. Lett. 17, 1523-1526.]). For ring conformation analysis, see Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc., 97, 1354-1358.]).

[Scheme 1]

Experimental

Crystal data
  • C10H9F3N2O2

  • Mr = 246.19

  • Monoclinic, P 21 /c

  • a = 8.6770 (9) Å

  • b = 10.0816 (11) Å

  • c = 11.6293 (12) Å

  • β = 95.747 (2)°

  • V = 1012.20 (18) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.15 mm−1

  • T = 296 K

  • 0.20 × 0.18 × 0.15 mm

Data collection
  • Bruker SMART APEX CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2000[Bruker (2000). SAINT, SMART and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.971, Tmax = 0.978

  • 6400 measured reflections

  • 2283 independent reflections

  • 2021 reflections with I > 2σ(I)

  • Rint = 0.028

Refinement
  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.112

  • S = 1.06

  • 2283 reflections

  • 170 parameters

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

  • Δρmax = 0.33 e Å−3

  • Δρmin = −0.28 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯O1i 0.91 (2) 2.17 (2) 3.0409 (16) 160.0 (18)
N2—H1B⋯O2ii 0.92 (2) 1.99 (2) 2.9075 (15) 175.3 (18)
O1—H1C⋯N1iii 0.82 (2) 2.02 (2) 2.8280 (16) 168 (2)
N1—H2A⋯F3iv 0.87 (2) 2.41 (2) 3.1124 (16) 138.5 (17)
C4—H4⋯F2v 0.93 2.31 3.1846 (16) 156
Symmetry codes: (i) x+1, y, z; (ii) -x+1, -y, -z; (iii) -x+1, -y, -z+1; (iv) [x+1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (v) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}].

Data collection: SMART (Bruker, 2000[Bruker (2000). SAINT, SMART and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2000[Bruker (2000). SAINT, SMART and SADABS. 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Owing to applications in biology and medicine, for example as orally available tissue-selective androgen receptor modulators, quinolinone and its derivatives have been extensively studied (Chilin, et al., 1991; Oeveren, et al., 2006). During a preparation of 7-amino-4-trifluoromethylquinolinone according to the published procedure (Oeveren, et al., 2007), 7-amino-4-hydroxy-4-(trifluoromethyl)-3,4-dihydroquinolin-2(1H)-one was unexpectedly obtained when a lower reaction temperature than that in the literature was employed. The product was characterized by 1H NMR and the structure confirmed by the present determination (Fig. 1).

In the title compound, the six-membered ring (C2, C3, N2, C8, C9, C10) adopts a non-classical conformation which is chracterized by the Cremer-Pople puckering parameters: Amplitude (Q) = 0.3577 (15) Å , Θ = 117.9 (2) ° , Φ = 44.6 (3) °) (Cremer & Pople 1975). Intermolecular C–H···F, N–H···F, O–H···N, O–H···O and N–H···O interactions link the molecules and contribute to the crystal packing (Fig. 2).

Related literature top

For general background to quinolinones, see: Chilin et al. (1991); Oeveren et al. (2006). For related structures, see: Oeveren et al. (2007). For ring conformation analysis, see Cremer & Pople (1975).

Experimental top

A mixture of m-phenylenediamine (100 mmol, 10.8 g) and ethyl 4,4,4-trifluoroacetoacetate (100 mmol, 15.2 mL) was heated at 353 K for 48 h. The cooled reaction mixture was suspended in 20 mL of methanol and the undissolved solid was collected. The pure product crystallized from ethanol to afford a white solid (80% yied, m.p. 501 K). 1H NMR (500 MHz, [D6] DMSO): δ 10.13 (bs, 1 H, NH), 7.16(d, J = 7.5 Hz, 1 H, 4-quin), 6.59(s, 1 H, OH), 6.23(d, J = 7.5 Hz, 1 H, 5-quin ), 6.10(d, J = 1.5 Hz, 1 H, 7-quin), 5.39(bs, 2 H, NH2 ), 2.83(dd, J = 1.6, 4.9 Hz, 2 H, 2-quin). Single crystals suitable for X-ray diffraction were obtained by evaporation of an ethanol solution.

Refinement top

All H atoms bonded to C atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances of 0.93–0.97 Å, and with Uiso(H) = 1.2Ueq(C). The other H atoms bonded to N and O atom were found in the difference maps and were refined independently.

Structure description top

Owing to applications in biology and medicine, for example as orally available tissue-selective androgen receptor modulators, quinolinone and its derivatives have been extensively studied (Chilin, et al., 1991; Oeveren, et al., 2006). During a preparation of 7-amino-4-trifluoromethylquinolinone according to the published procedure (Oeveren, et al., 2007), 7-amino-4-hydroxy-4-(trifluoromethyl)-3,4-dihydroquinolin-2(1H)-one was unexpectedly obtained when a lower reaction temperature than that in the literature was employed. The product was characterized by 1H NMR and the structure confirmed by the present determination (Fig. 1).

In the title compound, the six-membered ring (C2, C3, N2, C8, C9, C10) adopts a non-classical conformation which is chracterized by the Cremer-Pople puckering parameters: Amplitude (Q) = 0.3577 (15) Å , Θ = 117.9 (2) ° , Φ = 44.6 (3) °) (Cremer & Pople 1975). Intermolecular C–H···F, N–H···F, O–H···N, O–H···O and N–H···O interactions link the molecules and contribute to the crystal packing (Fig. 2).

For general background to quinolinones, see: Chilin et al. (1991); Oeveren et al. (2006). For related structures, see: Oeveren et al. (2007). For ring conformation analysis, see Cremer & Pople (1975).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A perspective view of the title compound . Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. Crystal packing viewed down the crystallographic c axis showing the hydrogen bonding interactions.
7-Amino-4-hydroxy-4-trifluoromethyl-3,4-dihydroquinolin-2(1H)-one top
Crystal data top
C10H9F3N2O2F(000) = 504
Mr = 246.19Dx = 1.616 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 4544 reflections
a = 8.6770 (9) Åθ = 2.4–30.4°
b = 10.0816 (11) ŵ = 0.15 mm1
c = 11.6293 (12) ÅT = 296 K
β = 95.747 (2)°Prism, yellow
V = 1012.20 (18) Å30.20 × 0.18 × 0.15 mm
Z = 4
Data collection top
Bruker SMART APEX CCD
diffractometer
2283 independent reflections
Radiation source: fine-focus sealed tube2021 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.028
φ and ω scansθmax = 27.5°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2000)
h = 1110
Tmin = 0.971, Tmax = 0.978k = 128
6400 measured reflectionsl = 1515
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)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.112H atoms treated by a mixture of independent and constrained refinement
S = 1.06 w = 1/[σ2(Fo2) + (0.0568P)2 + 0.3518P]
where P = (Fo2 + 2Fc2)/3
2283 reflections(Δ/σ)max < 0.001
170 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = 0.28 e Å3
Crystal data top
C10H9F3N2O2V = 1012.20 (18) Å3
Mr = 246.19Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.6770 (9) ŵ = 0.15 mm1
b = 10.0816 (11) ÅT = 296 K
c = 11.6293 (12) Å0.20 × 0.18 × 0.15 mm
β = 95.747 (2)°
Data collection top
Bruker SMART APEX CCD
diffractometer
2283 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2000)
2021 reflections with I > 2σ(I)
Tmin = 0.971, Tmax = 0.978Rint = 0.028
6400 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.112H atoms treated by a mixture of independent and constrained refinement
S = 1.06Δρmax = 0.33 e Å3
2283 reflectionsΔρmin = 0.28 e Å3
170 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
C10.12400 (17)0.21289 (16)0.23013 (12)0.0372 (3)
C20.19252 (14)0.08079 (13)0.27561 (10)0.0268 (3)
C30.35833 (14)0.10123 (13)0.32715 (10)0.0258 (3)
C40.39150 (15)0.15288 (14)0.43763 (11)0.0313 (3)
H40.31040.17480.48070.038*
C50.54182 (16)0.17229 (14)0.48484 (11)0.0316 (3)
H50.56130.20750.55880.038*
C60.66507 (14)0.13917 (13)0.42169 (11)0.0272 (3)
C70.63442 (14)0.08873 (14)0.31075 (10)0.0280 (3)
H70.71580.06690.26790.034*
C80.48175 (14)0.07080 (13)0.26335 (10)0.0254 (3)
C90.31363 (15)0.01002 (14)0.09840 (11)0.0292 (3)
C100.18645 (15)0.02086 (15)0.17766 (12)0.0340 (3)
H10A0.19030.10890.21140.041*
H10B0.08750.01220.13140.041*
F10.13125 (13)0.30710 (10)0.31014 (9)0.0552 (3)
F20.19747 (15)0.25830 (12)0.14294 (10)0.0652 (4)
F30.02624 (11)0.20090 (12)0.19086 (9)0.0572 (3)
N10.81794 (14)0.15133 (14)0.47467 (11)0.0333 (3)
N20.45399 (13)0.02567 (12)0.14878 (9)0.0309 (3)
O10.09075 (11)0.04442 (11)0.35806 (8)0.0334 (3)
O20.29139 (12)0.03941 (11)0.00459 (8)0.0377 (3)
H1B0.532 (2)0.026 (2)0.1011 (16)0.048 (5)*
H1A0.893 (3)0.136 (2)0.4276 (17)0.053 (5)*
H2A0.833 (2)0.225 (2)0.5140 (17)0.049 (5)*
H1C0.129 (2)0.013 (2)0.4017 (17)0.052 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0338 (7)0.0466 (8)0.0327 (7)0.0068 (6)0.0103 (6)0.0097 (6)
C20.0231 (6)0.0364 (7)0.0223 (5)0.0016 (5)0.0089 (4)0.0026 (5)
C30.0233 (6)0.0314 (6)0.0238 (6)0.0016 (5)0.0075 (4)0.0006 (5)
C40.0293 (6)0.0400 (7)0.0261 (6)0.0047 (5)0.0104 (5)0.0051 (5)
C50.0336 (7)0.0381 (7)0.0236 (6)0.0006 (5)0.0056 (5)0.0068 (5)
C60.0257 (6)0.0291 (6)0.0270 (6)0.0004 (5)0.0041 (5)0.0017 (5)
C70.0247 (6)0.0346 (7)0.0263 (6)0.0008 (5)0.0098 (5)0.0016 (5)
C80.0266 (6)0.0287 (6)0.0220 (6)0.0002 (5)0.0082 (4)0.0017 (5)
C90.0301 (6)0.0326 (7)0.0259 (6)0.0018 (5)0.0078 (5)0.0039 (5)
C100.0277 (6)0.0437 (8)0.0316 (7)0.0082 (5)0.0086 (5)0.0051 (6)
F10.0573 (6)0.0454 (6)0.0630 (7)0.0190 (5)0.0057 (5)0.0057 (5)
F20.0781 (8)0.0630 (7)0.0605 (7)0.0136 (6)0.0360 (6)0.0336 (6)
F30.0394 (5)0.0721 (7)0.0575 (6)0.0128 (5)0.0082 (4)0.0183 (5)
N10.0269 (6)0.0430 (7)0.0301 (6)0.0026 (5)0.0028 (5)0.0002 (5)
N20.0270 (5)0.0439 (7)0.0235 (5)0.0030 (5)0.0103 (4)0.0072 (5)
O10.0246 (5)0.0497 (6)0.0278 (5)0.0051 (4)0.0116 (4)0.0112 (4)
O20.0361 (5)0.0519 (6)0.0257 (5)0.0045 (4)0.0057 (4)0.0085 (4)
Geometric parameters (Å, º) top
C1—F11.3267 (19)C6—N11.4109 (17)
C1—F21.3318 (17)C7—C81.3947 (17)
C1—F31.3429 (18)C7—H70.9300
C1—C21.531 (2)C8—N21.4057 (16)
C2—O11.4153 (14)C9—O21.2301 (16)
C2—C31.5162 (17)C9—N21.3465 (17)
C2—C101.5292 (18)C9—C101.5110 (17)
C3—C41.3896 (17)C10—H10A0.9700
C3—C81.3966 (16)C10—H10B0.9700
C4—C51.3776 (19)N1—H1A0.91 (2)
C4—H40.9300N1—H2A0.87 (2)
C5—C61.3970 (17)N2—H1B0.92 (2)
C5—H50.9300O1—H1C0.82 (2)
C6—C71.3875 (18)
F1—C1—F2107.17 (14)C5—C6—N1119.03 (12)
F1—C1—F3106.21 (12)C6—C7—C8120.07 (11)
F2—C1—F3107.12 (12)C6—C7—H7120.0
F1—C1—C2113.02 (12)C8—C7—H7120.0
F2—C1—C2111.29 (12)C7—C8—C3120.67 (11)
F3—C1—C2111.68 (13)C7—C8—N2118.84 (10)
O1—C2—C3113.53 (10)C3—C8—N2120.46 (11)
O1—C2—C10110.72 (11)O2—C9—N2122.34 (12)
C3—C2—C10110.25 (10)O2—C9—C10121.57 (12)
O1—C2—C1102.26 (10)N2—C9—C10115.97 (11)
C3—C2—C1109.79 (11)C9—C10—C2115.66 (11)
C10—C2—C1110.02 (11)C9—C10—H10A108.4
C4—C3—C8118.34 (12)C2—C10—H10A108.4
C4—C3—C2121.13 (11)C9—C10—H10B108.4
C8—C3—C2120.52 (11)C2—C10—H10B108.4
C5—C4—C3121.46 (11)H10A—C10—H10B107.4
C5—C4—H4119.3C6—N1—H1A115.2 (13)
C3—C4—H4119.3C6—N1—H2A112.7 (13)
C4—C5—C6120.04 (12)H1A—N1—H2A112.4 (18)
C4—C5—H5120.0C9—N2—C8124.10 (11)
C6—C5—H5120.0C9—N2—H1B115.3 (12)
C7—C6—C5119.40 (11)C8—N2—H1B120.3 (12)
C7—C6—N1121.48 (11)C2—O1—H1C111.2 (14)
F1—C1—C2—O164.75 (14)C4—C5—C6—N1175.69 (13)
F2—C1—C2—O1174.61 (13)C5—C6—C7—C80.3 (2)
F3—C1—C2—O154.94 (14)N1—C6—C7—C8176.28 (12)
F1—C1—C2—C356.07 (14)C6—C7—C8—C31.0 (2)
F2—C1—C2—C364.58 (15)C6—C7—C8—N2176.92 (12)
F3—C1—C2—C3175.76 (11)C4—C3—C8—C71.62 (19)
F1—C1—C2—C10177.58 (11)C2—C3—C8—C7179.61 (12)
F2—C1—C2—C1056.93 (16)C4—C3—C8—N2176.26 (12)
F3—C1—C2—C1062.73 (14)C2—C3—C8—N22.50 (19)
O1—C2—C3—C434.07 (17)O2—C9—C10—C2147.86 (14)
C10—C2—C3—C4158.94 (12)N2—C9—C10—C236.06 (18)
C1—C2—C3—C479.68 (15)O1—C2—C10—C9167.21 (11)
O1—C2—C3—C8147.20 (12)C3—C2—C10—C940.75 (16)
C10—C2—C3—C822.32 (16)C1—C2—C10—C980.49 (15)
C1—C2—C3—C899.05 (14)O2—C9—N2—C8174.33 (13)
C8—C3—C4—C50.9 (2)C10—C9—N2—C89.6 (2)
C2—C3—C4—C5179.71 (13)C7—C8—N2—C9171.88 (13)
C3—C4—C5—C60.4 (2)C3—C8—N2—C910.2 (2)
C4—C5—C6—C71.0 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O1i0.91 (2)2.17 (2)3.0409 (16)160.0 (18)
N2—H1B···O2ii0.92 (2)1.99 (2)2.9075 (15)175.3 (18)
O1—H1C···N1iii0.82 (2)2.02 (2)2.8280 (16)168 (2)
N1—H2A···F3iv0.87 (2)2.41 (2)3.1124 (16)138.5 (17)
C4—H4···F2v0.932.313.1846 (16)156
Symmetry codes: (i) x+1, y, z; (ii) x+1, y, z; (iii) x+1, y, z+1; (iv) x+1, y+1/2, z+1/2; (v) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC10H9F3N2O2
Mr246.19
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)8.6770 (9), 10.0816 (11), 11.6293 (12)
β (°) 95.747 (2)
V3)1012.20 (18)
Z4
Radiation typeMo Kα
µ (mm1)0.15
Crystal size (mm)0.20 × 0.18 × 0.15
Data collection
DiffractometerBruker SMART APEX CCD
Absorption correctionMulti-scan
(SADABS; Bruker, 2000)
Tmin, Tmax0.971, 0.978
No. of measured, independent and
observed [I > 2σ(I)] reflections
6400, 2283, 2021
Rint0.028
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.112, 1.06
No. of reflections2283
No. of parameters170
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.33, 0.28

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O1i0.91 (2)2.17 (2)3.0409 (16)160.0 (18)
N2—H1B···O2ii0.92 (2)1.99 (2)2.9075 (15)175.3 (18)
O1—H1C···N1iii0.82 (2)2.02 (2)2.8280 (16)168 (2)
N1—H2A···F3iv0.87 (2)2.41 (2)3.1124 (16)138.5 (17)
C4—H4···F2v0.932.313.1846 (16)156.0
Symmetry codes: (i) x+1, y, z; (ii) x+1, y, z; (iii) x+1, y, z+1; (iv) x+1, y+1/2, z+1/2; (v) x, y+1/2, z+1/2.
 

Acknowledgements

We gratefully acknowledge financial support from the Natural Science Foundation of China (No. 20872051).

References

First citationBruker (2000). SAINT, SMART and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationChilin, A., Rodighiero, P., Pastorini, G. & Guiotto, A. (1991). J. Org. Chem. 56, 980–983.  CrossRef CAS Web of Science Google Scholar
First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc., 97, 1354–1358.  CrossRef CAS Web of Science Google Scholar
First citationOeveren, A. V., Motamedi, M., Mani, N. S., Marschke, K. B., Lopez, F. J., Schrader, W. T., Negro-Vilar, A. & Zhi, L. (2006). J. Med. Chem. 49, 6143–6146.  PubMed Google Scholar
First citationOeveren, A. V., Pio, B. A., Tegley, C. M., Higuchi, R. I., Wu, M., Jones, T. K., Marschke, K. B., Negro-Vilar, A. & Zhi, L. (2007). Bioorg. Med. Chem. Lett. 17, 1523–1526.  PubMed Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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