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In this contribution different solid-state forms of the racemic compound (RS)-2-(2-oxo-pyrrolidin-1yl)-butyramide are studied from a structural and thermal point of view. Three different solid-state phases were identified, including two polymorphs and one hydrate phase. Comparison is made with the structure of the (S)-enantiomer, for which only one solid-state phase is known. The basic structural motif found in both polymorphs of the racemic compound is similar, but the basic motif observed for the hydrate differs. These synthons could in principle be used in future polymorph prediction studies to screen for possible alternative forms of the enantiopure compound. Based on the structure of the hydrate, further efforts should therefore be made in order to identify a hydrate structure of the enantiopure compound. Studying the different phases of a racemic compound can therefore help to guide polymorphic screening of an enantiopure compound.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S2052519213015054/zb5029sup1.cif
Contains datablocks Etiracetam_FI, Etiracetam_FII, Etiracetam_Hydrate

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2052519213015054/zb5029Etiracetam_FIsup2.hkl
Contains datablock bn_tl-p1

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2052519213015054/zb5029Etiracetam_FIIsup3.hkl
Contains datablock bn_tl-etiracetam-ii

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2052519213015054/zb5029Etiracetam_Hydratesup4.hkl
Contains datablock bn_tl-etiracet-polymi

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S2052519213015054/zb5029sup5.pdf
Extra figures

CCDC references: 859779; 859780; 859781

Computing details top

Data collection: CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) for Etiracetam_FI. Cell refinement: CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) for Etiracetam_FI. Data reduction: CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) for Etiracetam_FI. Program(s) used to solve structure: sir92 for Etiracetam_FI. For all compounds, program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
[Figure 5]
[Figure 6]
[Figure 7]
[Figure 8]
[Figure 9]
[Figure 10]
[Figure 11]
[Figure 12]
(Etiracetam_FI) top
Crystal data top
C8H14N2O2F(000) = 368
Mr = 170.21Dx = 1.296 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3065 reflections
a = 9.5932 (3) Åθ = 3.4–32.5°
b = 7.8325 (3) ŵ = 0.09 mm1
c = 11.9547 (4) ÅT = 293 K
β = 103.830 (3)°Bipyramid, colorless
V = 872.22 (5) Å30.22 × 0.18 × 0.15 mm
Z = 4
Data collection top
Xcalibur, Ruby, Gemini ultra
diffractometer
2891 independent reflections
Radiation source: fine-focus sealed tube2102 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.017
Detector resolution: 10.3712 pixels mm-1θmax = 32.6°, θmin = 3.4°
ω scansh = 1414
Absorption correction: multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
k = 911
Tmin = 0.980, Tmax = 0.986l = 818
5882 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)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122H atoms treated by a mixture of independent and constrained refinement
S = 1.01 w = 1/[σ2(Fo2) + (0.077P)2]
where P = (Fo2 + 2Fc2)/3
2891 reflections(Δ/σ)max < 0.001
118 parametersΔρmax = 0.30 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C8H14N2O2V = 872.22 (5) Å3
Mr = 170.21Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.5932 (3) ŵ = 0.09 mm1
b = 7.8325 (3) ÅT = 293 K
c = 11.9547 (4) Å0.22 × 0.18 × 0.15 mm
β = 103.830 (3)°
Data collection top
Xcalibur, Ruby, Gemini ultra
diffractometer
2891 independent reflections
Absorption correction: multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
2102 reflections with I > 2σ(I)
Tmin = 0.980, Tmax = 0.986Rint = 0.017
5882 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0410 restraints
wR(F2) = 0.122H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.30 e Å3
2891 reflectionsΔρmin = 0.17 e Å3
118 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
C10.79178 (10)0.05261 (14)0.38805 (9)0.0374 (2)
H1A0.86760.02030.43120.045*
H1B0.83390.14080.34960.045*
C20.68108 (12)0.05037 (16)0.30221 (10)0.0451 (3)
H2A0.70070.04710.22630.054*
H2B0.68030.16840.32670.054*
C30.53957 (11)0.03635 (15)0.30150 (10)0.0427 (3)
H3A0.51400.11690.23820.051*
H3B0.46320.04710.29410.051*
C40.56468 (9)0.12746 (11)0.41579 (8)0.0309 (2)
C50.77402 (9)0.21574 (12)0.56912 (8)0.02737 (19)
H50.69650.25370.60380.033*
C60.87028 (9)0.09563 (12)0.65596 (8)0.02850 (19)
C70.85501 (11)0.37558 (13)0.54663 (9)0.0379 (2)
H7A0.89660.43120.61950.045*
H7B0.93300.34200.51250.045*
C80.75959 (13)0.50108 (16)0.46770 (12)0.0523 (3)
H8A0.73140.45390.39150.079*
H8B0.81110.60570.46560.079*
H8C0.67570.52340.49590.079*
N10.70754 (7)0.12708 (10)0.46327 (6)0.02767 (18)
N20.82835 (10)0.06625 (12)0.65596 (8)0.0386 (2)
O10.47334 (7)0.19244 (10)0.45907 (7)0.0419 (2)
O20.97979 (8)0.14929 (10)0.72218 (7)0.0431 (2)
H2C0.7450 (15)0.0998 (17)0.6112 (12)0.049 (4)*
H2D0.8786 (17)0.1362 (19)0.7068 (14)0.061 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0325 (5)0.0451 (6)0.0350 (5)0.0000 (4)0.0087 (4)0.0070 (4)
C20.0487 (6)0.0468 (6)0.0354 (5)0.0014 (5)0.0014 (5)0.0096 (5)
C30.0382 (5)0.0436 (6)0.0374 (5)0.0029 (4)0.0082 (4)0.0027 (4)
C40.0237 (4)0.0283 (4)0.0357 (5)0.0008 (3)0.0025 (3)0.0041 (4)
C50.0232 (4)0.0282 (4)0.0277 (4)0.0009 (3)0.0002 (3)0.0033 (3)
C60.0246 (4)0.0311 (4)0.0276 (4)0.0016 (3)0.0018 (3)0.0022 (3)
C70.0326 (5)0.0306 (5)0.0439 (6)0.0039 (4)0.0037 (4)0.0023 (4)
C80.0497 (6)0.0393 (6)0.0596 (8)0.0017 (5)0.0036 (6)0.0136 (5)
N10.0207 (3)0.0321 (4)0.0274 (4)0.0007 (3)0.0004 (3)0.0035 (3)
N20.0320 (4)0.0325 (4)0.0435 (5)0.0023 (3)0.0065 (4)0.0069 (4)
O10.0234 (3)0.0424 (4)0.0568 (5)0.0049 (3)0.0033 (3)0.0007 (3)
O20.0362 (4)0.0373 (4)0.0438 (4)0.0029 (3)0.0138 (3)0.0012 (3)
Geometric parameters (Å, º) top
C1—N11.4661 (12)C5—C71.5307 (13)
C1—C21.5200 (15)C5—C61.5354 (12)
C1—H1A0.9700C5—H50.9800
C1—H1B0.9700C6—O21.2285 (11)
C2—C31.5162 (16)C6—N21.3302 (13)
C2—H2A0.9700C7—C81.5105 (15)
C2—H2B0.9700C7—H7A0.9700
C3—C41.5089 (15)C7—H7B0.9700
C3—H3A0.9700C8—H8A0.9600
C3—H3B0.9700C8—H8B0.9600
C4—O11.2293 (12)C8—H8C0.9600
C4—N11.3523 (11)N2—H2C0.889 (14)
C5—N11.4507 (11)N2—H2D0.873 (16)
N1—C1—C2103.10 (8)N1—C5—H5107.1
N1—C1—H1A111.1C7—C5—H5107.1
C2—C1—H1A111.1C6—C5—H5107.1
N1—C1—H1B111.1O2—C6—N2122.56 (9)
C2—C1—H1B111.1O2—C6—C5120.63 (8)
H1A—C1—H1B109.1N2—C6—C5116.81 (8)
C3—C2—C1104.25 (9)C8—C7—C5112.63 (8)
C3—C2—H2A110.9C8—C7—H7A109.1
C1—C2—H2A110.9C5—C7—H7A109.1
C3—C2—H2B110.9C8—C7—H7B109.1
C1—C2—H2B110.9C5—C7—H7B109.1
H2A—C2—H2B108.9H7A—C7—H7B107.8
C4—C3—C2104.95 (8)C7—C8—H8A109.5
C4—C3—H3A110.8C7—C8—H8B109.5
C2—C3—H3A110.8H8A—C8—H8B109.5
C4—C3—H3B110.8C7—C8—H8C109.5
C2—C3—H3B110.8H8A—C8—H8C109.5
H3A—C3—H3B108.8H8B—C8—H8C109.5
O1—C4—N1125.25 (9)C4—N1—C5123.72 (8)
O1—C4—C3126.97 (8)C4—N1—C1113.29 (8)
N1—C4—C3107.78 (8)C5—N1—C1122.26 (7)
N1—C5—C7111.97 (8)C6—N2—H2C120.7 (9)
N1—C5—C6111.37 (7)C6—N2—H2D118.8 (10)
C7—C5—C6111.80 (7)H2C—N2—H2D120.1 (13)
N1—C1—C2—C325.12 (11)O1—C4—N1—C54.88 (15)
C1—C2—C3—C423.26 (11)C3—C4—N1—C5174.59 (8)
C2—C3—C4—O1168.09 (10)O1—C4—N1—C1175.25 (9)
C2—C3—C4—N112.45 (11)C3—C4—N1—C14.22 (11)
N1—C5—C6—O2146.74 (9)C7—C5—N1—C4106.79 (10)
C7—C5—C6—O220.64 (12)C6—C5—N1—C4127.20 (9)
N1—C5—C6—N233.81 (11)C7—C5—N1—C162.74 (11)
C7—C5—C6—N2159.91 (9)C6—C5—N1—C163.27 (11)
N1—C5—C7—C858.15 (12)C2—C1—N1—C418.93 (11)
C6—C5—C7—C8176.08 (10)C2—C1—N1—C5170.54 (9)
(Etiracetam_FII) top
Crystal data top
C8H14N2O2Z = 4
Mr = 170.21F(000) = 368
Monoclinic, P21/cDx = 1.260 Mg m3
a = 9.3020 (8) ÅMo Kα radiation, λ = 0.71073 Å
b = 11.5223 (7) ŵ = 0.09 mm1
c = 8.4172 (5) ÅT = 293 K
β = 95.966 (7)°0.20 × 0.10 × 0.04 mm
V = 897.27 (11) Å3
Data collection top
Xcalibur, Ruby, Gemini ultra
diffractometer
2982 independent reflections
Radiation source: fine-focus sealed tube878 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.064
Detector resolution: 10.3712 pixels mm-1θmax = 32.6°, θmin = 3.5°
ω scansh = 1013
Absorption correction: multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
k = 1017
Tmin = 0.982, Tmax = 0.996l = 1212
5986 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)] = 0.052Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.146H atoms treated by a mixture of independent and constrained refinement
S = 0.66 w = 1/[σ2(Fo2) + (0.0709P)2]
where P = (Fo2 + 2Fc2)/3
2982 reflections(Δ/σ)max < 0.001
110 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C8H14N2O2V = 897.27 (11) Å3
Mr = 170.21Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.3020 (8) ŵ = 0.09 mm1
b = 11.5223 (7) ÅT = 293 K
c = 8.4172 (5) Å0.20 × 0.10 × 0.04 mm
β = 95.966 (7)°
Data collection top
Xcalibur, Ruby, Gemini ultra
diffractometer
2982 independent reflections
Absorption correction: multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
878 reflections with I > 2σ(I)
Tmin = 0.982, Tmax = 0.996Rint = 0.064
5986 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0520 restraints
wR(F2) = 0.146H atoms treated by a mixture of independent and constrained refinement
S = 0.66Δρmax = 0.19 e Å3
2982 reflectionsΔρmin = 0.17 e Å3
110 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
C10.8260 (2)0.03766 (18)0.4563 (2)0.0281 (5)
C20.7499 (3)0.0084 (2)0.5927 (2)0.0393 (6)
C30.6682 (3)0.1139 (2)0.5251 (3)0.0488 (7)
H3A0.56930.11230.55180.059*
H3B0.71390.18440.56830.059*
C40.6716 (3)0.10935 (19)0.3462 (3)0.0415 (6)
H4A0.57840.08600.29330.050*
H4B0.69740.18430.30500.050*
C50.8281 (2)0.00310 (17)0.1662 (2)0.0280 (5)
H50.90570.06070.18250.034*
C60.8920 (2)0.10431 (17)0.0933 (3)0.0310 (5)
C70.7084 (3)0.0570 (2)0.0539 (3)0.0465 (7)
H7A0.63170.00040.03170.056*
H7B0.74610.07530.04630.056*
C80.6452 (3)0.1665 (2)0.1194 (4)0.0685 (9)
H8A0.72070.22250.14350.103*
H8B0.57330.19800.04110.103*
H8C0.60170.14810.21480.103*
N10.78199 (18)0.02277 (13)0.32354 (19)0.0270 (4)
N20.9744 (2)0.17279 (16)0.1912 (2)0.0407 (5)
H2C1.01550.23240.15430.049*
H2D0.98670.15760.29180.049*
O10.91207 (17)0.11918 (12)0.46377 (17)0.0403 (4)
O20.87115 (19)0.12224 (13)0.05084 (18)0.0492 (5)
H2A0.81830.01770.70190.080*
H2B0.67130.06160.62450.080*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0335 (13)0.0252 (11)0.0260 (12)0.0049 (11)0.0052 (9)0.0005 (10)
C20.0506 (16)0.0422 (13)0.0274 (12)0.0054 (12)0.0145 (11)0.0011 (11)
C30.0604 (18)0.0421 (14)0.0476 (16)0.0078 (13)0.0227 (13)0.0057 (13)
C40.0447 (16)0.0394 (13)0.0425 (15)0.0141 (12)0.0149 (12)0.0056 (12)
C50.0345 (12)0.0266 (11)0.0237 (11)0.0015 (10)0.0071 (9)0.0009 (9)
C60.0354 (14)0.0320 (12)0.0269 (12)0.0063 (11)0.0106 (10)0.0011 (10)
C70.0512 (17)0.0529 (15)0.0352 (13)0.0122 (13)0.0034 (12)0.0026 (12)
C80.077 (2)0.0574 (17)0.0707 (19)0.0297 (17)0.0068 (17)0.0072 (16)
N10.0336 (10)0.0255 (9)0.0233 (9)0.0056 (8)0.0092 (8)0.0009 (8)
N20.0546 (14)0.0391 (11)0.0284 (10)0.0146 (10)0.0040 (10)0.0061 (9)
O10.0523 (11)0.0323 (8)0.0364 (10)0.0147 (8)0.0044 (8)0.0037 (7)
O20.0775 (14)0.0488 (10)0.0227 (9)0.0099 (9)0.0112 (8)0.0071 (8)
Geometric parameters (Å, º) top
C1—O11.232 (2)C5—C71.516 (3)
C1—N11.344 (2)C5—C61.529 (3)
C1—C21.506 (3)C5—H50.9800
C2—C31.513 (3)C6—O21.226 (2)
C2—H2A1.0679C6—N21.326 (3)
C2—H2B1.1392C7—C81.520 (3)
C3—C41.510 (3)C7—H7A0.9700
C3—H3A0.9700C7—H7B0.9700
C3—H3B0.9700C8—H8A0.9600
C4—N11.459 (2)C8—H8B0.9600
C4—H4A0.9700C8—H8C0.9600
C4—H4B0.9700N2—H2C0.8600
C5—N11.464 (2)N2—H2D0.8600
O1—C1—N1125.28 (19)N1—C5—H5107.0
O1—C1—C2125.78 (19)C7—C5—H5107.0
N1—C1—C2108.93 (18)C6—C5—H5107.0
C1—C2—C3104.75 (17)O2—C6—N2122.5 (2)
C1—C2—H2A114.0O2—C6—C5120.4 (2)
C3—C2—H2A118.3N2—C6—C5117.11 (19)
C1—C2—H2B107.1C8—C7—C5113.6 (2)
C3—C2—H2B110.4C8—C7—H7A108.8
H2A—C2—H2B102.0C5—C7—H7A108.8
C4—C3—C2106.55 (17)C8—C7—H7B108.8
C4—C3—H3A110.4C5—C7—H7B108.8
C2—C3—H3A110.4H7A—C7—H7B107.7
C4—C3—H3B110.4C7—C8—H8A109.5
C2—C3—H3B110.4C7—C8—H8B109.5
H3A—C3—H3B108.6H8A—C8—H8B109.5
N1—C4—C3104.02 (18)C7—C8—H8C109.5
N1—C4—H4A111.0H8A—C8—H8C109.5
C3—C4—H4A111.0H8B—C8—H8C109.5
N1—C4—H4B111.0C1—N1—C5123.66 (17)
C3—C4—H4B111.0C1—N1—C4113.77 (17)
H4A—C4—H4B109.0C5—N1—C4122.27 (17)
N1—C5—C7112.48 (18)C6—N2—H2C120.0
N1—C5—C6111.16 (16)C6—N2—H2D120.0
C7—C5—C6111.84 (17)H2C—N2—H2D120.0
O1—C1—C2—C3175.1 (2)O1—C1—N1—C52.0 (3)
N1—C1—C2—C36.5 (2)C2—C1—N1—C5176.48 (17)
C1—C2—C3—C412.7 (2)O1—C1—N1—C4175.8 (2)
C2—C3—C4—N114.0 (2)C2—C1—N1—C42.7 (2)
N1—C5—C6—O2143.52 (19)C7—C5—N1—C1107.8 (2)
C7—C5—C6—O216.9 (3)C6—C5—N1—C1125.9 (2)
N1—C5—C6—N239.2 (3)C7—C5—N1—C465.5 (2)
C7—C5—C6—N2165.81 (19)C6—C5—N1—C460.8 (3)
N1—C5—C7—C856.1 (3)C3—C4—N1—C110.6 (2)
C6—C5—C7—C8178.0 (2)C3—C4—N1—C5175.46 (18)
(Etiracetam_Hydrate) top
Crystal data top
C8H14N2O2·H2OZ = 2
Mr = 188.23F(000) = 204
Triclinic, P1Dx = 1.252 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.2006 (5) ÅCell parameters from 2333 reflections
b = 7.9639 (5) Åθ = 3.4–32.6°
c = 9.5468 (6) ŵ = 0.10 mm1
α = 85.293 (5)°T = 293 K
β = 76.031 (6)°Prism, colourless
γ = 70.023 (6)°0.20 × 0.18 × 0.14 mm
V = 499.30 (6) Å3
Data collection top
Xcalibur, Ruby, Gemini ultra
diffractometer
3290 independent reflections
Radiation source: fine-focus sealed tube2015 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.023
Detector resolution: 10.3712 pixels mm-1θmax = 32.7°, θmin = 3.4°
ω scansh = 1010
Absorption correction: multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
k = 1012
Tmin = 0.981, Tmax = 0.987l = 1313
5863 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)] = 0.047Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.134H atoms treated by a mixture of independent and constrained refinement
S = 0.94 w = 1/[σ2(Fo2) + (0.0762P)2]
where P = (Fo2 + 2Fc2)/3
3290 reflections(Δ/σ)max < 0.001
135 parametersΔρmax = 0.24 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C8H14N2O2·H2Oγ = 70.023 (6)°
Mr = 188.23V = 499.30 (6) Å3
Triclinic, P1Z = 2
a = 7.2006 (5) ÅMo Kα radiation
b = 7.9639 (5) ŵ = 0.10 mm1
c = 9.5468 (6) ÅT = 293 K
α = 85.293 (5)°0.20 × 0.18 × 0.14 mm
β = 76.031 (6)°
Data collection top
Xcalibur, Ruby, Gemini ultra
diffractometer
3290 independent reflections
Absorption correction: multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
2015 reflections with I > 2σ(I)
Tmin = 0.981, Tmax = 0.987Rint = 0.023
5863 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0470 restraints
wR(F2) = 0.134H atoms treated by a mixture of independent and constrained refinement
S = 0.94Δρmax = 0.24 e Å3
3290 reflectionsΔρmin = 0.21 e Å3
135 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
C10.64229 (18)0.12134 (16)0.59858 (13)0.0423 (3)
C20.7691 (2)0.06906 (18)0.61925 (17)0.0581 (4)
H2A0.90900.09180.56750.070*
H2B0.71700.15130.58490.070*
C30.7538 (2)0.08979 (18)0.78088 (17)0.0565 (4)
H3A0.88500.15700.80100.068*
H3B0.65810.15060.82470.068*
C40.68020 (19)0.10033 (17)0.83719 (14)0.0450 (3)
H4A0.58260.11340.92900.054*
H4B0.79260.13450.84880.054*
C50.48294 (15)0.39969 (14)0.73852 (11)0.0329 (2)
H50.45410.44280.64430.039*
C60.27817 (15)0.44750 (15)0.84804 (12)0.0343 (2)
C70.61868 (17)0.49527 (16)0.77067 (14)0.0431 (3)
H7A0.64970.45660.86390.052*
H7B0.54640.62290.77590.052*
C80.8161 (2)0.4582 (2)0.65597 (17)0.0574 (4)
H8A0.89120.33260.65370.086*
H8B0.89540.52330.67860.086*
H8C0.78610.49540.56340.086*
N10.58525 (13)0.20777 (12)0.72503 (9)0.0328 (2)
N20.19197 (16)0.32228 (15)0.88046 (13)0.0457 (3)
O10.59756 (19)0.19044 (14)0.48629 (10)0.0669 (3)
O20.19811 (12)0.59925 (11)0.90024 (10)0.0470 (2)
O30.24206 (17)0.04415 (15)0.79030 (14)0.0612 (3)
H2C0.074 (3)0.350 (2)0.9484 (18)0.062 (4)*
H2D0.244 (2)0.217 (2)0.8393 (17)0.056 (4)*
H3C0.219 (3)0.141 (3)0.835 (2)0.101 (7)*
H3D0.287 (3)0.087 (3)0.703 (2)0.080 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0467 (6)0.0387 (6)0.0358 (6)0.0147 (5)0.0039 (5)0.0065 (5)
C20.0600 (8)0.0349 (7)0.0634 (9)0.0104 (6)0.0104 (7)0.0088 (6)
C30.0514 (8)0.0395 (7)0.0757 (10)0.0096 (6)0.0190 (7)0.0056 (7)
C40.0459 (7)0.0435 (7)0.0429 (7)0.0115 (5)0.0122 (5)0.0070 (5)
C50.0322 (5)0.0309 (5)0.0291 (5)0.0063 (4)0.0004 (4)0.0023 (4)
C60.0300 (5)0.0360 (6)0.0321 (5)0.0069 (4)0.0036 (4)0.0017 (4)
C70.0363 (6)0.0374 (6)0.0515 (7)0.0130 (5)0.0018 (5)0.0091 (5)
C80.0393 (7)0.0526 (8)0.0722 (10)0.0180 (6)0.0071 (6)0.0026 (7)
N10.0323 (4)0.0297 (5)0.0311 (5)0.0067 (3)0.0025 (4)0.0015 (4)
N20.0349 (5)0.0408 (6)0.0546 (7)0.0134 (4)0.0067 (5)0.0105 (5)
O10.1057 (9)0.0562 (6)0.0325 (5)0.0205 (6)0.0116 (5)0.0066 (4)
O20.0395 (4)0.0366 (5)0.0529 (5)0.0074 (3)0.0070 (4)0.0087 (4)
O30.0726 (7)0.0530 (6)0.0564 (7)0.0241 (5)0.0016 (5)0.0163 (5)
Geometric parameters (Å, º) top
C1—O11.2265 (17)C5—C61.5329 (14)
C1—N11.3430 (15)C5—H50.9800
C1—C21.5046 (19)C6—O21.2351 (13)
C2—C31.520 (2)C6—N21.3248 (16)
C2—H2A0.9700C7—C81.5238 (16)
C2—H2B0.9700C7—H7A0.9700
C3—C41.5199 (18)C7—H7B0.9700
C3—H3A0.9700C8—H8A0.9600
C3—H3B0.9700C8—H8B0.9600
C4—N11.4661 (15)C8—H8C0.9600
C4—H4A0.9700N2—H2C0.906 (17)
C4—H4B0.9700N2—H2D0.877 (17)
C5—N11.4535 (13)O3—H3C0.90 (3)
C5—C71.5234 (16)O3—H3D0.87 (2)
O1—C1—N1124.36 (12)C7—C5—H5106.8
O1—C1—C2127.01 (12)C6—C5—H5106.8
N1—C1—C2108.63 (11)O2—C6—N2122.57 (10)
C1—C2—C3105.22 (11)O2—C6—C5119.90 (10)
C1—C2—H2A110.7N2—C6—C5117.51 (10)
C3—C2—H2A110.7C5—C7—C8112.04 (10)
C1—C2—H2B110.7C5—C7—H7A109.2
C3—C2—H2B110.7C8—C7—H7A109.2
H2A—C2—H2B108.8C5—C7—H7B109.2
C2—C3—C4104.63 (11)C8—C7—H7B109.2
C2—C3—H3A110.8H7A—C7—H7B107.9
C4—C3—H3A110.8C7—C8—H8A109.5
C2—C3—H3B110.8C7—C8—H8B109.5
C4—C3—H3B110.8H8A—C8—H8B109.5
H3A—C3—H3B108.9C7—C8—H8C109.5
N1—C4—C3103.67 (10)H8A—C8—H8C109.5
N1—C4—H4A111.0H8B—C8—H8C109.5
C3—C4—H4A111.0C1—N1—C5122.66 (10)
N1—C4—H4B111.0C1—N1—C4113.10 (10)
C3—C4—H4B111.0C5—N1—C4122.51 (9)
H4A—C4—H4B109.0C6—N2—H2C117.1 (10)
N1—C5—C7111.85 (9)C6—N2—H2D123.1 (9)
N1—C5—C6112.16 (9)H2C—N2—H2D119.8 (14)
C7—C5—C6111.99 (9)H3C—O3—H3D97.8 (18)
N1—C5—H5106.8
O1—C1—C2—C3172.82 (13)O1—C1—N1—C57.39 (19)
N1—C1—C2—C37.85 (15)C2—C1—N1—C5171.96 (10)
C1—C2—C3—C418.25 (15)O1—C1—N1—C4172.75 (12)
C2—C3—C4—N121.53 (13)C2—C1—N1—C46.60 (14)
N1—C5—C6—O2160.91 (10)C7—C5—N1—C1110.21 (12)
C7—C5—C6—O234.20 (15)C6—C5—N1—C1122.99 (11)
N1—C5—C6—N220.47 (14)C7—C5—N1—C453.78 (13)
C7—C5—C6—N2147.19 (11)C6—C5—N1—C473.01 (12)
N1—C5—C7—C857.15 (13)C3—C4—N1—C118.14 (13)
C6—C5—C7—C8175.96 (10)C3—C4—N1—C5176.48 (9)

Experimental details

(Etiracetam_FI)(Etiracetam_FII)(Etiracetam_Hydrate)
Crystal data
Chemical formulaC8H14N2O2C8H14N2O2C8H14N2O2·H2O
Mr170.21170.21188.23
Crystal system, space groupMonoclinic, P21/cMonoclinic, P21/cTriclinic, P1
Temperature (K)293293293
a, b, c (Å)9.5932 (3), 7.8325 (3), 11.9547 (4)9.3020 (8), 11.5223 (7), 8.4172 (5)7.2006 (5), 7.9639 (5), 9.5468 (6)
α, β, γ (°)90, 103.830 (3), 9090, 95.966 (7), 9085.293 (5), 76.031 (6), 70.023 (6)
V3)872.22 (5)897.27 (11)499.30 (6)
Z442
Radiation typeMo KαMo KαMo Kα
µ (mm1)0.090.090.10
Crystal size (mm)0.22 × 0.18 × 0.150.20 × 0.10 × 0.040.20 × 0.18 × 0.14
Data collection
DiffractometerXcalibur, Ruby, Gemini ultra
diffractometer
Xcalibur, Ruby, Gemini ultra
diffractometer
Xcalibur, Ruby, Gemini ultra
diffractometer
Absorption correctionMulti-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
Multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
Multi-scan
CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
Tmin, Tmax0.980, 0.9860.982, 0.9960.981, 0.987
No. of measured, independent and
observed [I > 2σ(I)] reflections
5882, 2891, 2102 5986, 2982, 878 5863, 3290, 2015
Rint0.0170.0640.023
(sin θ/λ)max1)0.7580.7570.759
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.122, 1.01 0.052, 0.146, 0.66 0.047, 0.134, 0.94
No. of reflections289129823290
No. of parameters118110135
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.30, 0.170.19, 0.170.24, 0.21

Computer programs: CrysAlis PRO, Oxford Diffraction Ltd., Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET) (compiled Jan 5 2010,16:28:46), sir92, SHELXL97 (Sheldrick, 1997).

 

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