organic compounds
(S)-(+)-Ketamine hydrochloride
aDepartment of Chemistry, Syracuse University, Syracuse, New York 13244, USA
*Correspondence e-mail: wouellet@syr.edu
The S)-(+)-N-[1-(2-chlorophenyl)-2-oxocyclohexyl]methanaminium chloride}, C13H17ClNO+·Cl−, was determined at 90 (2) K. The (S)-(+)-ketamine hydrochloride salt is a well known anesthetic compound and is dramatically more potent than its R isomer. In the title compound, the cyclohexanone ring adopts a chair conformation with the oxo group in the equatorial orientation. The methylamino and 2-chlorophenyl groups at the 2-position have an equatorial and an axial orientation, respectively. The packing of ions is stabilized by an infinite one-dimensional ⋯Cl⋯H—N—H⋯Cl⋯ hydrogen-bonding network, involving NH2+ groups as donors and chloride anions as acceptors.
of the title compound {systematic name: (Related literature
For related literature, see: Chankvetadze et al. (2002); Domino et al. (1965); Marhofer et al. (2001); Mathisen et al. (1995); Pees et al. (2003); Reich & Silvay (1989); Smirnova et al. (1989); White et al. (1985); Wolff & Winstock (2006).
Experimental
Crystal data
|
Data collection: SMART (Bruker, 2002); cell SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Supporting information
10.1107/S1600536808021053/bh2181sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808021053/bh2181Isup2.hkl
All material used for this work was purchased from Sigma-Aldrich (minimum 99% pure) and used without further purification. The
of the was verified by measuring the of the material using a Jasco DIP-1000 digital polarimeter. The determined from anomalous dispersion-effects is consistent with the expected enantiomer.H atoms were located in a difference map and refined freely. The C—H and N—H bond lengths range from 0.91 (2) to 1.014 (17) and 0.83 (3) to 0.869 (18) Å, respectively.
Data collection: SMART (Bruker, 2002); cell
SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C13H17ClNO·Cl | F(000) = 288 |
Mr = 274.18 | Dx = 1.374 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 3471 reflections |
a = 8.4338 (4) Å | θ = 2.5–28.2° |
b = 7.0715 (4) Å | µ = 0.47 mm−1 |
c = 11.3524 (6) Å | T = 90 K |
β = 101.875 (1)° | Rod, colourless |
V = 662.56 (6) Å3 | 0.50 × 0.12 × 0.10 mm |
Z = 2 |
Bruker APEX CCD area-detector diffractometer | 3251 independent reflections |
Radiation source: fine-focus sealed tube | 3146 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
Detector resolution: 512 pixels mm-1 | θmax = 28.3°, θmin = 1.8° |
ϕ and ω scans | h = −11→11 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2008) | k = −9→9 |
Tmin = 0.798, Tmax = 0.954 | l = −15→15 |
6985 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.027 | All H-atom parameters refined |
wR(F2) = 0.066 | w = 1/[σ2(Fo2) + (0.0378P)2 + 0.0273P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max = 0.001 |
3251 reflections | Δρmax = 0.31 e Å−3 |
223 parameters | Δρmin = −0.17 e Å−3 |
1 restraint | Absolute structure: Flack (1983), 1472 Friedel pairs |
0 constraints | Absolute structure parameter: 0.00 (5) |
Primary atom site location: structure-invariant direct methods |
C13H17ClNO·Cl | V = 662.56 (6) Å3 |
Mr = 274.18 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 8.4338 (4) Å | µ = 0.47 mm−1 |
b = 7.0715 (4) Å | T = 90 K |
c = 11.3524 (6) Å | 0.50 × 0.12 × 0.10 mm |
β = 101.875 (1)° |
Bruker APEX CCD area-detector diffractometer | 3251 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2008) | 3146 reflections with I > 2σ(I) |
Tmin = 0.798, Tmax = 0.954 | Rint = 0.020 |
6985 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | All H-atom parameters refined |
wR(F2) = 0.066 | Δρmax = 0.31 e Å−3 |
S = 1.07 | Δρmin = −0.17 e Å−3 |
3251 reflections | Absolute structure: Flack (1983), 1472 Friedel pairs |
223 parameters | Absolute structure parameter: 0.00 (5) |
1 restraint |
x | y | z | Uiso*/Ueq | ||
Cl2 | 0.05227 (4) | 0.23769 (5) | 0.35081 (3) | 0.01627 (9) | |
Cl1 | 0.34238 (5) | −0.13679 (5) | 0.87212 (4) | 0.02248 (10) | |
O1 | 0.38001 (14) | −0.03746 (17) | 0.60012 (10) | 0.0205 (2) | |
N1 | 0.11098 (16) | 0.1291 (2) | 0.62148 (11) | 0.0132 (3) | |
C1 | 0.27185 (19) | 0.0822 (2) | 0.90899 (14) | 0.0157 (3) | |
C2 | 0.2437 (2) | 0.0998 (3) | 1.02456 (15) | 0.0212 (3) | |
C3 | 0.1889 (2) | 0.2691 (3) | 1.06202 (16) | 0.0239 (4) | |
C4 | 0.1635 (2) | 0.4199 (3) | 0.98344 (15) | 0.0218 (4) | |
C5 | 0.19088 (19) | 0.4012 (2) | 0.86757 (15) | 0.0175 (3) | |
C6 | 0.24628 (16) | 0.2315 (3) | 0.82673 (13) | 0.0140 (3) | |
C7 | 0.26395 (16) | 0.2136 (2) | 0.69555 (12) | 0.0124 (3) | |
C8 | 0.40443 (19) | 0.0878 (2) | 0.67428 (13) | 0.0155 (3) | |
C9 | 0.57016 (19) | 0.1543 (2) | 0.73576 (15) | 0.0176 (3) | |
C10 | 0.59821 (19) | 0.3492 (3) | 0.68330 (14) | 0.0175 (3) | |
C11 | 0.46277 (19) | 0.4860 (2) | 0.69619 (15) | 0.0166 (3) | |
C12 | 0.29711 (19) | 0.4052 (2) | 0.63815 (14) | 0.0142 (3) | |
C13 | −0.04410 (18) | 0.2160 (3) | 0.63712 (14) | 0.0170 (3) | |
H11B | 0.471 (2) | 0.511 (3) | 0.7848 (19) | 0.024 (5)* | |
H12A | 0.294 (2) | 0.378 (3) | 0.5499 (16) | 0.014 (4)* | |
H13A | −0.060 (2) | 0.181 (3) | 0.7166 (17) | 0.015 (5)* | |
H10B | 0.603 (2) | 0.334 (3) | 0.6003 (17) | 0.016 (5)* | |
H9A | 0.649 (2) | 0.055 (3) | 0.7199 (18) | 0.024 (5)* | |
H1B | 0.116 (2) | 0.140 (3) | 0.5461 (17) | 0.008 (4)* | |
H10A | 0.703 (3) | 0.397 (3) | 0.7211 (17) | 0.021 (5)* | |
H13B | −0.126 (2) | 0.167 (3) | 0.5775 (18) | 0.021 (5)* | |
H9B | 0.574 (2) | 0.167 (3) | 0.8215 (18) | 0.018 (5)* | |
H5 | 0.174 (2) | 0.503 (3) | 0.8174 (19) | 0.023 (5)* | |
H12B | 0.209 (2) | 0.490 (3) | 0.6419 (16) | 0.018 (5)* | |
H3 | 0.166 (2) | 0.278 (3) | 1.1373 (19) | 0.026 (6)* | |
H2 | 0.259 (2) | −0.003 (3) | 1.0735 (17) | 0.015 (5)* | |
H4 | 0.128 (2) | 0.542 (3) | 1.0038 (18) | 0.022 (5)* | |
H13C | −0.038 (2) | 0.351 (3) | 0.6318 (16) | 0.018 (5)* | |
H1A | 0.105 (3) | 0.015 (4) | 0.6352 (18) | 0.024 (5)* | |
H11A | 0.483 (3) | 0.601 (4) | 0.6570 (18) | 0.029 (6)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl2 | 0.02035 (17) | 0.01438 (16) | 0.01376 (16) | 0.00042 (14) | 0.00279 (12) | −0.00059 (13) |
Cl1 | 0.0302 (2) | 0.01408 (17) | 0.02266 (19) | 0.00260 (16) | 0.00414 (15) | 0.00452 (14) |
O1 | 0.0253 (6) | 0.0180 (6) | 0.0188 (6) | 0.0042 (5) | 0.0059 (5) | −0.0035 (5) |
N1 | 0.0159 (6) | 0.0117 (6) | 0.0117 (6) | 0.0003 (5) | 0.0019 (5) | −0.0008 (5) |
C1 | 0.0155 (7) | 0.0150 (7) | 0.0163 (7) | −0.0006 (6) | 0.0020 (6) | 0.0008 (6) |
C2 | 0.0197 (8) | 0.0285 (9) | 0.0145 (7) | −0.0054 (7) | 0.0016 (6) | 0.0048 (7) |
C3 | 0.0211 (8) | 0.0358 (11) | 0.0159 (8) | −0.0058 (7) | 0.0064 (6) | −0.0049 (7) |
C4 | 0.0192 (8) | 0.0261 (9) | 0.0203 (8) | −0.0013 (6) | 0.0048 (6) | −0.0092 (7) |
C5 | 0.0170 (7) | 0.0169 (8) | 0.0180 (7) | 0.0013 (6) | 0.0022 (6) | −0.0013 (6) |
C6 | 0.0129 (6) | 0.0164 (7) | 0.0126 (6) | −0.0008 (6) | 0.0026 (5) | −0.0003 (6) |
C7 | 0.0130 (6) | 0.0126 (7) | 0.0113 (6) | 0.0003 (6) | 0.0015 (5) | 0.0006 (6) |
C8 | 0.0192 (8) | 0.0145 (7) | 0.0135 (7) | 0.0044 (6) | 0.0053 (6) | 0.0035 (6) |
C9 | 0.0148 (7) | 0.0197 (8) | 0.0183 (8) | 0.0046 (6) | 0.0038 (6) | 0.0024 (6) |
C10 | 0.0159 (7) | 0.0200 (8) | 0.0171 (7) | −0.0001 (6) | 0.0044 (6) | 0.0002 (6) |
C11 | 0.0171 (7) | 0.0143 (7) | 0.0186 (8) | −0.0001 (6) | 0.0042 (6) | 0.0012 (6) |
C12 | 0.0153 (7) | 0.0127 (7) | 0.0146 (7) | 0.0003 (5) | 0.0028 (5) | 0.0013 (5) |
C13 | 0.0149 (7) | 0.0163 (8) | 0.0197 (7) | −0.0001 (6) | 0.0033 (5) | −0.0022 (7) |
Cl1—C1 | 1.7403 (16) | C7—C8 | 1.540 (2) |
O1—C8 | 1.210 (2) | C7—C12 | 1.553 (2) |
N1—C13 | 1.488 (2) | C8—C9 | 1.503 (2) |
N1—C7 | 1.5108 (19) | C9—C10 | 1.539 (2) |
N1—H1B | 0.869 (18) | C9—H9A | 1.01 (2) |
N1—H1A | 0.83 (3) | C9—H9B | 0.97 (2) |
C1—C2 | 1.386 (2) | C10—C11 | 1.527 (2) |
C1—C6 | 1.397 (2) | C10—H10B | 0.957 (18) |
C2—C3 | 1.382 (3) | C10—H10A | 0.96 (2) |
C2—H2 | 0.91 (2) | C11—C12 | 1.528 (2) |
C3—C4 | 1.378 (3) | C11—H11B | 1.01 (2) |
C3—H3 | 0.92 (2) | C11—H11A | 0.96 (2) |
C4—C5 | 1.388 (2) | C12—H12A | 1.014 (17) |
C4—H4 | 0.96 (2) | C12—H12B | 0.96 (2) |
C5—C6 | 1.401 (2) | C13—H13A | 0.971 (19) |
C5—H5 | 0.91 (2) | C13—H13B | 0.93 (2) |
C6—C7 | 1.5321 (19) | C13—H13C | 0.96 (2) |
C13—N1—C7 | 116.17 (12) | C9—C8—C7 | 114.74 (13) |
C13—N1—H1B | 107.8 (12) | C8—C9—C10 | 107.60 (13) |
C7—N1—H1B | 107.7 (12) | C8—C9—H9A | 106.5 (12) |
C13—N1—H1A | 106.8 (15) | C10—C9—H9A | 113.3 (12) |
C7—N1—H1A | 111.3 (15) | C8—C9—H9B | 109.6 (12) |
H1B—N1—H1A | 106.7 (19) | C10—C9—H9B | 109.0 (12) |
C2—C1—C6 | 122.11 (15) | H9A—C9—H9B | 110.8 (16) |
C2—C1—Cl1 | 116.19 (13) | C11—C10—C9 | 110.66 (13) |
C6—C1—Cl1 | 121.69 (12) | C11—C10—H10B | 110.3 (11) |
C3—C2—C1 | 120.18 (16) | C9—C10—H10B | 108.8 (12) |
C3—C2—H2 | 121.6 (12) | C11—C10—H10A | 111.8 (13) |
C1—C2—H2 | 118.2 (12) | C9—C10—H10A | 110.1 (13) |
C4—C3—C2 | 119.23 (15) | H10B—C10—H10A | 105.0 (16) |
C4—C3—H3 | 121.0 (14) | C10—C11—C12 | 110.94 (14) |
C2—C3—H3 | 119.7 (14) | C10—C11—H11B | 108.0 (12) |
C3—C4—C5 | 120.40 (16) | C12—C11—H11B | 111.3 (12) |
C3—C4—H4 | 123.7 (13) | C10—C11—H11A | 106.8 (14) |
C5—C4—H4 | 115.9 (13) | C12—C11—H11A | 110.4 (13) |
C4—C5—C6 | 121.81 (16) | H11B—C11—H11A | 109.3 (17) |
C4—C5—H5 | 118.8 (13) | C11—C12—C7 | 111.90 (12) |
C6—C5—H5 | 119.4 (13) | C11—C12—H12A | 109.5 (10) |
C1—C6—C5 | 116.27 (13) | C7—C12—H12A | 106.2 (12) |
C1—C6—C7 | 123.69 (15) | C11—C12—H12B | 113.2 (13) |
C5—C6—C7 | 119.89 (14) | C7—C12—H12B | 108.5 (12) |
N1—C7—C6 | 109.33 (11) | H12A—C12—H12B | 107.2 (15) |
N1—C7—C8 | 106.29 (12) | N1—C13—H13A | 107.3 (11) |
C6—C7—C8 | 115.60 (12) | N1—C13—H13B | 107.4 (12) |
N1—C7—C12 | 108.57 (11) | H13A—C13—H13B | 111.0 (17) |
C6—C7—C12 | 113.44 (13) | N1—C13—H13C | 110.3 (11) |
C8—C7—C12 | 103.13 (11) | H13A—C13—H13C | 109.3 (16) |
O1—C8—C9 | 124.09 (15) | H13B—C13—H13C | 111.5 (17) |
O1—C8—C7 | 120.38 (14) | ||
C6—C1—C2—C3 | −0.2 (2) | C5—C6—C7—C8 | 146.41 (14) |
Cl1—C1—C2—C3 | 179.44 (13) | C1—C6—C7—C12 | −157.03 (14) |
C1—C2—C3—C4 | −0.3 (3) | C5—C6—C7—C12 | 27.58 (18) |
C2—C3—C4—C5 | 0.7 (3) | N1—C7—C8—O1 | 6.73 (18) |
C3—C4—C5—C6 | −0.7 (3) | C6—C7—C8—O1 | 128.23 (15) |
C2—C1—C6—C5 | 0.2 (2) | C12—C7—C8—O1 | −107.40 (16) |
Cl1—C1—C6—C5 | −179.37 (11) | N1—C7—C8—C9 | 177.01 (12) |
C2—C1—C6—C7 | −175.34 (14) | C6—C7—C8—C9 | −61.50 (17) |
Cl1—C1—C6—C7 | 5.1 (2) | C12—C7—C8—C9 | 62.88 (15) |
C4—C5—C6—C1 | 0.2 (2) | O1—C8—C9—C10 | 107.30 (17) |
C4—C5—C6—C7 | 175.93 (14) | C7—C8—C9—C10 | −62.57 (16) |
C13—N1—C7—C6 | 48.63 (18) | C8—C9—C10—C11 | 55.38 (17) |
C13—N1—C7—C8 | 174.05 (13) | C9—C10—C11—C12 | −55.57 (17) |
C13—N1—C7—C12 | −75.59 (16) | C10—C11—C12—C7 | 59.27 (17) |
C1—C6—C7—N1 | 81.64 (16) | N1—C7—C12—C11 | −171.44 (12) |
C5—C6—C7—N1 | −93.75 (17) | C6—C7—C12—C11 | 66.81 (16) |
C1—C6—C7—C8 | −38.2 (2) | C8—C7—C12—C11 | −58.97 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···Cl2i | 0.83 (3) | 2.39 (3) | 3.1359 (15) | 151 (2) |
N1—H1B···Cl2 | 0.869 (19) | 2.278 (19) | 3.1065 (13) | 159.4 (17) |
Symmetry code: (i) −x, y−1/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C13H17ClNO·Cl |
Mr | 274.18 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 90 |
a, b, c (Å) | 8.4338 (4), 7.0715 (4), 11.3524 (6) |
β (°) | 101.875 (1) |
V (Å3) | 662.56 (6) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.47 |
Crystal size (mm) | 0.50 × 0.12 × 0.10 |
Data collection | |
Diffractometer | Bruker APEX CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2008) |
Tmin, Tmax | 0.798, 0.954 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6985, 3251, 3146 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.066, 1.07 |
No. of reflections | 3251 |
No. of parameters | 223 |
No. of restraints | 1 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.31, −0.17 |
Absolute structure | Flack (1983), 1472 Friedel pairs |
Absolute structure parameter | 0.00 (5) |
Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), CrystalMaker (Palmer, 2006), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···Cl2i | 0.83 (3) | 2.39 (3) | 3.1359 (15) | 151 (2) |
N1—H1B···Cl2 | 0.869 (19) | 2.278 (19) | 3.1065 (13) | 159.4 (17) |
Symmetry code: (i) −x, y−1/2, −z+1. |
Acknowledgements
The authors gratefully acknowledge the support of the National Science Foundation (CHE-0604527). PMH expresses his gratitude to the Syracuse University and STEM Fellowship programs.
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Wolff, K. & Winstock, A. R. (2006). CNS Drugs, 20, 199–218. Web of Science CrossRef PubMed CAS Google Scholar
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The title compound, (S)-(+)-ketamine hydrochloride, has been investigated by single-crystal X-ray diffraction at 90 (2) K (Fig. 1 and 2). The use of ketamine has been shown to lead to a state of dissociative anesthesia (Domino et al., 1965). This study focuses on the S isomer of the well known anesthetic compound ketamine hydrochloride because it is dramatically more potent than its R isomer (White et al., 1985). The pure S isomer is available commercially as Ketanest STM, while the racemic mixture, containing both S and R isomers is available under many names, including: KetalarTM, KetanestTM, and KetajectTM (Marhofer et al., 2001; Wolff & Winstock, 2006). Both the S and R isomers of neutral ketamine have been structurally characterized by X-ray diffraction in an earlier investigation (Chankvetadze et al., 2002). The compound is listed as a Schedule III controlled substance by the Federal government of the United States (Wolff & Winstock, 2006). Ketamine hydrochloride was first investigated in the 1960's and is a derivative of the more dangerous psychotomimetic drug, Phencyclidine (Domino et al., 1965). The chirality of Ketamine can be attributed to the C2 position, located on the cyclohexanone ring (Reich & Silvay, 1989). The potency of the drug is dependent upon its conformation, with the S isomer displaying analgesic effects roughly 4 times greater than those displayed by the levorotatory enantiomer R-(-)-Ketamine in controlling the pain of postoperative patients (Mathisen et al., 1995). In comparison to the racemic mixture, the S-isomer produces analgesic and anesthetic effects with twice the potency of the racemic (White et al., 1985). Increased potency enables the use of a much lower dosage while still producing the required effect, in turn leading to a quicker recovery time from the anesthesia (Pees et al., 2003). The potential advantages of the S isomer over the racemic mixture have lead to an increase in clinical use of the enantiomerically pure compound, particularly in Europe (Marhofer et al., 2001). The potency, the increasing clinical usage, and the strong potential for abuse of (S)-(+)-Ketamine hydrochloride, provide a need for the complete characterization of this molecule, and its previously unpublished crystal structure. An unequivocal understanding of the solid-state crystal structure of the compound is a necessity for detection and identification methods such as THz vibrational spectroscopy, or solid-state NMR, among others. This study has determined that the compound crystallizes in the monoclinic space group P21, with a unit cell volume of 662.56 (6) Å3 at 90 K, and Z value 2. The complete atomic coordinates have also been determined.