Home Physical Sciences Important impurity of Flupirtine – a single crystal study on ethyl (6-amino-5-((ethoxycarbonyl)amino)pyridin-2-yl)(4-fluorobenzyl)carbamate, C18H21FN4O4
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Important impurity of Flupirtine – a single crystal study on ethyl (6-amino-5-((ethoxycarbonyl)amino)pyridin-2-yl)(4-fluorobenzyl)carbamate, C18H21FN4O4

  • Kun-Yan Wang EMAIL logo and Xiao-Li Yang
Published/Copyright: May 31, 2017
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Zeitschrift für Kristallographie - New Crystal Structures
From the journal Zeitschrift für Kristallographie - New Crystal Structures Volume 232 Issue 4

Abstract

C18H21FN4O4, monoclinic, P21/n (no. 14), a = 9.4973(8) Å, b = 12.8420(11) Å, c = 15.3050(15) Å, β = 103.468(4)°, V = 1815.3(3) Å3, Z = 4, Rgt(F) = 0.0525, wRref(F2) = 0.1049, T = 296(2) K.

CCDC no.:: 1546441

The molecular structure of the title compound together with a symmetry related hydrogen bonded one is shown in the figure. Tables 1 and 2 contain details of the measurement method and a list of the atoms including atomic coordinates and displacement parameters.

Table 1

Data collection and handling.

Crystal:Colourless block
Size:0.29 × 0.18 × 0.12 mm
Wavelength:Mo Kα radiation (0.71073 Å)
μ:1.1 cm−1
Diffractometer, scan mode:PHOTON100 CMOS, ω scans
2θmax, completeness:50.6°, 99%
N(hkl)measured, N(hkl)unique, Rint:9199, 3281, 0.061
Criterion for Iobs, N(hkl)gt:Iobs > 2 σ(Iobs), 2147
N(param)refined:302
Programs:CAD-4 [1], XCAD-4 [2], SHELX [3, 4]
Table 2

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2).

AtomxyzUiso*/Ueq
C10.7383(2)0.43485(17)0.66649(15)0.0192(5)
C20.7452(2)0.40704(18)0.75377(15)0.0225(5)
H20.83510.40530.79680.027*
C30.6167(2)0.38142(18)0.77762(15)0.0222(5)
H30.61810.36120.83750.027*
C40.4875(2)0.38551(17)0.71416(14)0.0182(5)
C50.4896(2)0.42064(17)0.62640(14)0.0176(5)
C60.9564(2)0.38959(19)0.61642(14)0.0227(5)
C70.9925(3)0.21082(19)0.59230(16)0.0296(6)
H7A1.08270.20750.64020.036*
H7B1.01850.22400.53430.036*
C80.9106(3)0.1107(2)0.58825(19)0.0411(7)
H8A0.88580.09840.64610.062*
H8B0.97060.05330.57530.062*
H8C0.82160.11490.54070.062*
C90.9180(3)0.57061(18)0.65325(16)0.0266(6)
H9A0.83550.61840.63160.032*
H9B0.99110.58460.61800.032*
C101.0958(3)0.6212(2)0.93177(18)0.0442(8)
C110.9614(3)0.6597(2)0.89452(18)0.0396(7)
H110.90780.69640.92990.048*
C120.9055(3)0.64393(19)0.80403(17)0.0306(6)
H120.81120.66890.77730.037*
C130.9836(2)0.59248(18)0.75109(16)0.0245(6)
C141.1210(3)0.5559(2)0.79206(18)0.0344(6)
H141.17670.52090.75700.041*
C151.1776(3)0.5699(2)0.88321(19)0.0425(7)
H151.27110.54440.91120.051*
F11.1522(2)0.63555(16)1.02208(11).0715(6)
N10.61415(19)0.44371(14)0.60388(12)0.0192(4)
N20.86732(19)0.46238(15)0.63776(12)0.0213(5)
N30.3536(2)0.35416(16)0.73026(13)0.0231(5)
H3A0.280(3)0.3542(19)0.6858(16)0.028*
N40.3666(2)0.42961(18)0.56009(14)0.0292(5)
H4A0.373(3)0.4639(19)0.5099(17)0.035*
H4B0.286(3)0.431(2)0.5725(16)0.035*
O10.89920(16)0.29366(12)0.61133(10)0.0270(4)
O21.07529(16)0.40864(13)0.60204(10)0.0293(4)
C16a0.3291(8)0.3220(8)0.8094(5)0.0302(16)
O3a0.1955(8)0.2802(12)0.942(6)0.0330(18)
O4a0.4105(7)0.3318(8)0.8818(3)0.0489(18)
C17a0.1434(7)0.2603(7)0.8769(4)0.0356(15)
H17Aa0.11190.32580.90070.043*
H17Ba0.22020.22780.92390.043*
C18a0.0173(12)0.1869(11)0.8466(10)0.040(2)
H18Aa−0.06110.22300.80460.060*
H18Ba−0.01730.16350.89890.060*
H18Ca0.04840.12660.81670.060*
C16′b0.3340(16)0.3099(15)0.8072(9)0.031(3)
O3′b0.1921(16)0.290(3)0.8021(13)0.033(2)
O4′b0.4290(13)0.2862(10)0.8722(7)0.032(2)
C17′b0.1713(13)0.2144(14)0.8734(8)0.038(2)
H17Cb0.21870.14710.86690.046*
H17Db0.21290.24250.93420.046*
C18′b0.013(2)0.201(3)0.859(2)0.045(5)
H18Db−0.03520.26850.84730.068*
H18Eb−0.00950.16970.91280.068*
H18Fb−0.02230.15460.80740.068*

  1. aOccupancy: 0.670(15); bOccupancy: 0.330(15).

Source of material

The title compound can be easily synthesized according to a known patent [5]. To a solution of 2,3-diamino-6-(4-fluorobenzylamino)pyridine (10 g, 43.11 mmol) in degassed ethyl acetate (100 mL) were added ethyl carbonochloridate (5.6 g, 51.73 mmol) and triethylamine (5.7 g, 56.03 mmol) slowly in 1 h. The mixture was stirred under nitrogen for 4 h at 40 °C before the solvent was removed in vacuum. The crude product was purified by flash chromatography on silica gel eluting with 0% increasing to 5% methanol in dichloromethane. The product was obtained as a pale yellow solid (811.3 mg, 5%). In a typical experiment 0.1 g of the title compound was dissolved in 6 mL methanol. Evaporation at room temperature yielded colourless crystals of the title compound.

Experimental details

All hydrogen atoms were identified in difference Fourier syntheses. The hydrogen atoms were placed on calculated positions with the SHELX program (AFIX 43, 23 or 137 option) [4] and refined using a riding model: N—H = 0.86 Å, C—H = 0.93 and 0.96 Å for aromatic and CH3 H atoms, respectively, with Uiso(H) = k times Ueq(N,C), where k = 1.5 for CH3 H atoms and k = 1.2 for other H atoms.

Comment

The title compound, is an important impurity of Flupirtine. It is a by-product of chloroacetylation of the synthetic protocol [5]. Flupirtine is an aminopyridine that acts as a centrally acting non-opioid analgesic. This drug has been originally used as an analgesic for acute and chronic pain. It has been shown that Flupiritine is a neuronal potassium channel opener (SNEPCO) [6].

The bond lengths and angles in the title structure are within normal ranges [7]. The title compound is composed of two rings, a 4-fluoro phenyl moiety (C10—C11—C12—C13—C14—C15) and a pyridyl core (C1—C2—C3—C4—C5—N1). The latter is not exactly planar. The dihedral angle between the two ring systems is 45.4(2)°. In the crystal of the title compound, there are intermolecular N–H⋯N hydrogen bonds which link adjacent molecules pairwise. In the crystal structure, there are additional weak π-π stacking interactions.

Acknowledgement

This work is supported by PhD Research Startup Foundation of Jinling Institute of Technology (JIT-B-201323, JIT-B-201211, JIT-B-201601). We also thank the Center of Testing and Analysis, Nanjing University.

References

1 Enraf-Nonius. CAD-4 Software. Version 5.0. Enraf-Nonius, Delft, The Netherlands (1985).Search in Google Scholar

2 Harms, K.; Wocadlo, S.: XCAD4. University of Marburg, Germany (1995).Search in Google Scholar

3 North, A. C. T.; Phillips, D. C.; Mathews, F. S.: A semi-empirical method of absorption correction. Acta Crystallogr. A24 (1968) 351–359.10.1107/S0567739468000707Search in Google Scholar

4 Sheldrick, G. M.: A short history of SHELX. Acta Crystallogr. A64 (2008) 112–122.10.1107/S0108767307043930Search in Google Scholar PubMed

5 Martin, S. J.; Garnett, A.: Process for the preparation of flupirtine maleate. WO 2012/004391 A1.Search in Google Scholar

6 Kumar, R.; Kesheri, U. P.; Sharma, J.: Flupirtine: a mini review. J. Drug Deliv. Ther. 3 (2013) 113–116.10.22270/jddt.v3i6.705Search in Google Scholar

7 Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen, A. G.; Taylor, R.: Tables of bond lengths determined by X-ray and neutron diffraction. J. Chem. Soc. Perkin Trans. 2 (1987) S1–S19.10.1039/p298700000s1Search in Google Scholar

Received: 2016-12-21
Accepted: 2017-5-3
Published Online: 2017-5-31
Published in Print: 2017-7-26

©2017 Kun-Yan Wang et al., published by De Gruyter, Berlin/Boston

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Articles in the same Issue

  1. Cover and Frontmatter
  2. Crystal structure of poly[diaqua-(μ2-4,4′-bipyridine-κ2N:N′)manganese(II)] bis(4-chlorobenzenesulfonate) – 4,4′-bipyridine – water (1/1/2) C42H40Cl2MnN6O10S2
  3. The crystal structure of 1,2-bis[2-methyl-5-(3-cyanophenyl)-3-thienyl]-3,3,4,4,5,5-hexafluoro-cyclopent-1-ene, C29H16F6N2S2
  4. Crystal structure of the first characterized polymeric copper and sodium complex diaqua-(tris-acetato-κO,O′)(μ2-acetato-κO′′)dinatrium copper(II) monohydrate, C8H18CuNa2O11
  5. The crystal structure of the Schiff base (E)-2,6-diisopropyl-N-(pyridin-3-yl-methylene)aniline, C18H22N2
  6. Crystal structure of methyl 2,7,7-trimethyl-4-(4-nitrophenyl)-5-oxo-1,4,5,6,7,8-hexahydro-quinoline-3-carboxylate, C20H22N2O5
  7. Crystal structure of bis(1,3-bis(diphenylphosphino)propane-κ2P,P′)silver(I) trifluorosulfonate–methanol (1:0.5), [Ag(C27H26P2)]SO3CF3⋅0.5CH3OH
  8. Crystal structure of μ-1,4-bis(diphenylphosphine)butane-2,9-dimethyl-1,10-phenanthroline-κ2N:N′-bis(cyano-κC)dicopper(I)]-water, C58H56Cu2N6O2P2
  9. Crystal structure of N2,N6-bis(1-hydrazinyl-2-methyl-1-oxopropan-2-yl) pyridine-2,6-dicarboxamide, C15H23N7O4
  10. Crystal structure of 1,3-dimethyl-2-phenyl-1H-perimidin-3-ium iodide, C19H17IN2
  11. Crystal structure of diaqua-(2,2′-(butane-1,4-diyl)-bis(5-carboxy-1H-imidazole-4-carboxylato)-κ4O,O′,N,N′)cadmium(II) monohydrate, C14H18O11N4Cd
  12. Crystal structure of ethyl (E)-3-(cyclopropylamino)-2-(2,4-dichloro-5-fluorobenzoyl) acrylate, C15H14Cl2FNO3
  13. Crystal structure of bis-(1-(4-chlorophenyl)-3-phenyl-4-thenoyl-1H-pyrazol-5-ol-κ2O,O′)-(N,N-dimethylformamide)zinc(II), C43H31Cl2N5O5S2Zn
  14. Crystal structure of tetrakis(μ3-2-(N-(2-hydroxyethyl)amino)ethoxo)-tetrachloro-tetra-cobalt(II) methanol solvate, C17H44Cl4Co4N4O9
  15. Crystal structure of 3-amino-1-(4-bromophenyl)-9-methoxy-1H-benzo[f]chromene-2-carbonitrile, C21H15BrN2O2
  16. Crystal structure of 2-amino-4-(4-isopropyl-phenyl)-3-cyano-5-oxo-4H,5H-pyrano[3,2-c]chromene, C22H18N2O3
  17. Crystal structure of 3-amino-8-methoxy-1-(4-methoxy phenyl)-1H-benzo[f]chromene-2-carbonitrile, C22H18N2O3
  18. Crystal structure of monoaqua-[6,6′-((1E,1′E)-(1,2-phenylene bis(azanylylidene))bis(methanylylidene))bis(4-bromo-2-nitrophenolato-κ4N,N′,O,O′)]zinc(II), C20H12Br2N4O7Zn
  19. Crystal structure of 11-(4-(dimethylamino)phenyl)-17-hydroxy-13-methyl-17-(prop-1-yn-1-yl)-1,2,6,7,8,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthren-3-one – acetonitril (1/2), C33H41N3O2
  20. Crystal structure of tert-butyl (phenylsulfinyl)carbamate, C11H15NO3S
  21. Crystal structure of catena-poly{diaqua-bis(3-(1H-1,2,4-triazol-1-yl)benzoato-κ2O:N)copper(II)} monohydrate, C18H18CuN6O7
  22. Crystal structure of tetraaqua-bis(3-(4H-1,2,4-triazol-4-yl)benzoato-κN)cobalt(II), C18H20CoN6O8
  23. The crystal structure of 4-bromo-N-cyclopropyl-2,5-difluorobenzenesulfonamide, C9H8BrF2NO2S
  24. Crystal structure of ([3,3′-bipyridine]-6,6′-dicarboxylato-κ2O:O′)-bis(1,2-bis(4-pyridyl)ethane-κ2N:N′)disilver(I) dihydrate, C37H35Ag2N5O6
  25. The crystal structure of (4-(1H-1,2,4-triazol-1-yl)benzoato-κN)-[4-(1H-1,2,4-triazol-1-yl)benzoic acid-κN]silver(I), C18H13AgN6O4
  26. Crystal structure of 3-(4-methoxyphenyl)-1-(4-methylphenyl)prop-2-en-1-one, C17H16O2
  27. Crystal structure of bis(2-((E)-((4-((E)-1-(ethoxyimino)ethyl)phenyl)imino)methyl)-5-methoxyphenolato-κ2O,N)copper(II), C36H38CuN4O6
  28. Crystal structure of poly[1,2-bis(1,2,4-triazol-4-yl)ethane-κ2N:N′]silver(I) bromate monohydrate]silver(I), C6H10AgBrN6O4
  29. The crystal structure of 2,3,5-triphenyl-2,3-dihydro-1H-tetrazol-1-ium 2,3-dioxoindoline-5-sulfonate, C27H19N5O5S
  30. Crystal structure of 3-(2-amino-1,3-selenazol-4-yl)-2H-chromen-2-one – dimethylformamide (1/1), C15H15N3O3Se
  31. Crystal structure of diethyl 3,3′-(diazene-1,2-diyl)(E)-dibenzoate, C18H18N2O4
  32. Crystal structure of cis-bis((1H-benzimidazol-2-yl)methanol-κN,O)-bis(isothiocyanato-κN)nickel(II), C18H16N6NiO2S2
  33. Crystal structure of bis(2-(2′-hydroxy-5′-methoxyphenyl)-1H-benzimidazole)boron – tetrahydrofuran (1/1), C36H37N4O6B
  34. Crystal structure of poly[aqua-bis(nitrato-κ2O,O′)-(μ3-1,3-benzimidazol-3-ium-1,3-diacetato-κ4O,O′:O′′:O′′′)dysprosium(III)], C11H11DyN4O11
  35. Crystal structure of n-butyl-tris(dicyclo-hexylamido)hafnium(IV), C40H75HfN3
  36. Crystal structure of (E)-1-[1-(3-chloro-4-fluoro-phenyl)ethylidene]-2-(2,4-dinitrophenyl)hydrazine, C28H20Cl2F2N8O8
  37. The crystal structure of ethyl 4-((2-hydroxybenzyl)amino)benzoate, a Schiff base, C16H17NO3
  38. Crystal structure of 3-(2-(4-isobutylphenyl)propanoyl)-1-methylimidazolidine-2,4-dione, C17H22N2O3
  39. Crystal structure of poly[(μ3-2-(pyrazin-2-ylthio)acetato-κ3N:O:S)silver(I)], C6H5AgN2O2S
  40. Crystal structure of (E)-1-(3-((E)-((2-hydroxynaphthalen-1-yl)methylene)amino)phenyl)ethanone O-benzyl oxime, C26H22N2O2
  41. Crystal structure of (E)-2,3-dihydroxybenzaldehyde O-(2-((((E)-1-(2,5-dihydroxyphenyl)ethylidene)amino)oxy)ethyl) oxime monohydrate, C17H20N2O7
  42. Crystal structure of 4-(chloromethyl)-3-nitrobenzoic acid, C8H6ClNO4
  43. Crystal stucture of 4-((10H-phenothiazin-10-yl)methyl)-2,6-di-tert-butylphenol, C27H31NOS
  44. The crystal structure of ethyl 1-(4-nitrophenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate, C13H10F3N3O4
  45. Crystal structure of catena-poly[di-(μ3-oxido-κ3O:O:O)-tetraoxido-(μ2-5′-(pyrazin-2-yl)-1H,2′H-3,3′-bi(1,2,4-triazole)-κ2N:N′)dimolybdenum(VI)], C8H6Mo2N8O6
  46. Crystal structure of (3,6-dioxocyclohexa-1,4-diene-1,4-bis(olato)-κ4O,O′:O′′,O′′′)-bis(tris(2-pyridylmethyl)amine-κ4N,N′,N′′,N′′′))-dizinc(II) bis(hexafluorophosphate(V)), C42H38F12N8O4P2Zn2
  47. Crystal structure of catena-poly[hexakis(μ2-2-acetylphenolato-κ3O:O,O′)trimanganese(II)], C48H42Mn3O12
  48. The crystal structure of 2,2-difluoro-4-(trifluoromethyl)-2,5-dihydro-[1,3,2]dioxaborinino[5,4-c]chromen-3-ium-2-uide, C11H6BF5O3
  49. Crystal structure of methyl (E)-2-(4-(diethylamino)-2-hydroxybenzylidene)hydrazine-1-carboxylate, C13H19N3O3
  50. The crystal structure of tert-butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate, C10H15N3O2
  51. Crystal structure of 1,1-bis(η5-adamantylcyclopentadienyl)-3-phenyl-2-trimethylsilyl-2,3-dihydroisotitanazole, C42H55NSiTi
  52. Crystal structure of 2-(4-(2-(4-benzylpiperazin-1-yl)ethyl)benzyl)isoindoline-1,3-dione, C28H29N3O2
  53. Important impurity of Flupirtine – a single crystal study on ethyl (6-amino-5-((ethoxycarbonyl)amino)pyridin-2-yl)(4-fluorobenzyl)carbamate, C18H21FN4O4
  54. Crystal structure of ethyl 3-(4-methoxyphenyl)-1-(2-(4-methoxyphenyl)-2-oxoethyl)-1H-pyrazole-5-carboxylate, C22H22N2O5
  55. Crystal structure of 2,3,9,10-tetramethoxy-5,6-dihydroisoquinolino[2,1-b]isoquinolin-7-ium 5-hydroxy-3-(4-hydroxyphenyl)-4-oxo-4H-chromen-7-olate methanol solvate, C37H35N1O10
  56. The crystal structure of the inner salt of 2-[(aminoiminomethyl)amino]ethylcarbamic acid [systematic name: (2-((diaminomethylene)ammonio)ethyl)carbamate], C4H10N4O2
  57. Crystal structure of (8-hydroxy-5-nitroquinolinium) perchlorate – 8-hydroxy-5-nitroquinoline (1/1), C18H13ClN4O10
  58. The crystal structure of (5-methyl-1,2,4-oxadiazol-3-yl)ferrocene, C13H12FeN2O
  59. Crystal structure of methyl 1-(2-(fluorosulfonyl)ethyl)-2-oxocyclopentanecarboxylate, C9H13FO5S
  60. Crystal structure of the triclinic modification of 1-methyl-4-nitroimidzole, C4H5N3O2
  61. Corrigendum
  62. Crystal structure of 4-bromo-2-(1H-pyrazol-3-yl)phenol, C9H7BrN2O
https://doi.org/10.1515/ncrs-2016-0406
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Articles in the same Issue

  1. Cover and Frontmatter
  2. Crystal structure of poly[diaqua-(μ2-4,4′-bipyridine-κ2N:N′)manganese(II)] bis(4-chlorobenzenesulfonate) – 4,4′-bipyridine – water (1/1/2) C42H40Cl2MnN6O10S2
  3. The crystal structure of 1,2-bis[2-methyl-5-(3-cyanophenyl)-3-thienyl]-3,3,4,4,5,5-hexafluoro-cyclopent-1-ene, C29H16F6N2S2
  4. Crystal structure of the first characterized polymeric copper and sodium complex diaqua-(tris-acetato-κO,O′)(μ2-acetato-κO′′)dinatrium copper(II) monohydrate, C8H18CuNa2O11
  5. The crystal structure of the Schiff base (E)-2,6-diisopropyl-N-(pyridin-3-yl-methylene)aniline, C18H22N2
  6. Crystal structure of methyl 2,7,7-trimethyl-4-(4-nitrophenyl)-5-oxo-1,4,5,6,7,8-hexahydro-quinoline-3-carboxylate, C20H22N2O5
  7. Crystal structure of bis(1,3-bis(diphenylphosphino)propane-κ2P,P′)silver(I) trifluorosulfonate–methanol (1:0.5), [Ag(C27H26P2)]SO3CF3⋅0.5CH3OH
  8. Crystal structure of μ-1,4-bis(diphenylphosphine)butane-2,9-dimethyl-1,10-phenanthroline-κ2N:N′-bis(cyano-κC)dicopper(I)]-water, C58H56Cu2N6O2P2
  9. Crystal structure of N2,N6-bis(1-hydrazinyl-2-methyl-1-oxopropan-2-yl) pyridine-2,6-dicarboxamide, C15H23N7O4
  10. Crystal structure of 1,3-dimethyl-2-phenyl-1H-perimidin-3-ium iodide, C19H17IN2
  11. Crystal structure of diaqua-(2,2′-(butane-1,4-diyl)-bis(5-carboxy-1H-imidazole-4-carboxylato)-κ4O,O′,N,N′)cadmium(II) monohydrate, C14H18O11N4Cd
  12. Crystal structure of ethyl (E)-3-(cyclopropylamino)-2-(2,4-dichloro-5-fluorobenzoyl) acrylate, C15H14Cl2FNO3
  13. Crystal structure of bis-(1-(4-chlorophenyl)-3-phenyl-4-thenoyl-1H-pyrazol-5-ol-κ2O,O′)-(N,N-dimethylformamide)zinc(II), C43H31Cl2N5O5S2Zn
  14. Crystal structure of tetrakis(μ3-2-(N-(2-hydroxyethyl)amino)ethoxo)-tetrachloro-tetra-cobalt(II) methanol solvate, C17H44Cl4Co4N4O9
  15. Crystal structure of 3-amino-1-(4-bromophenyl)-9-methoxy-1H-benzo[f]chromene-2-carbonitrile, C21H15BrN2O2
  16. Crystal structure of 2-amino-4-(4-isopropyl-phenyl)-3-cyano-5-oxo-4H,5H-pyrano[3,2-c]chromene, C22H18N2O3
  17. Crystal structure of 3-amino-8-methoxy-1-(4-methoxy phenyl)-1H-benzo[f]chromene-2-carbonitrile, C22H18N2O3
  18. Crystal structure of monoaqua-[6,6′-((1E,1′E)-(1,2-phenylene bis(azanylylidene))bis(methanylylidene))bis(4-bromo-2-nitrophenolato-κ4N,N′,O,O′)]zinc(II), C20H12Br2N4O7Zn
  19. Crystal structure of 11-(4-(dimethylamino)phenyl)-17-hydroxy-13-methyl-17-(prop-1-yn-1-yl)-1,2,6,7,8,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthren-3-one – acetonitril (1/2), C33H41N3O2
  20. Crystal structure of tert-butyl (phenylsulfinyl)carbamate, C11H15NO3S
  21. Crystal structure of catena-poly{diaqua-bis(3-(1H-1,2,4-triazol-1-yl)benzoato-κ2O:N)copper(II)} monohydrate, C18H18CuN6O7
  22. Crystal structure of tetraaqua-bis(3-(4H-1,2,4-triazol-4-yl)benzoato-κN)cobalt(II), C18H20CoN6O8
  23. The crystal structure of 4-bromo-N-cyclopropyl-2,5-difluorobenzenesulfonamide, C9H8BrF2NO2S
  24. Crystal structure of ([3,3′-bipyridine]-6,6′-dicarboxylato-κ2O:O′)-bis(1,2-bis(4-pyridyl)ethane-κ2N:N′)disilver(I) dihydrate, C37H35Ag2N5O6
  25. The crystal structure of (4-(1H-1,2,4-triazol-1-yl)benzoato-κN)-[4-(1H-1,2,4-triazol-1-yl)benzoic acid-κN]silver(I), C18H13AgN6O4
  26. Crystal structure of 3-(4-methoxyphenyl)-1-(4-methylphenyl)prop-2-en-1-one, C17H16O2
  27. Crystal structure of bis(2-((E)-((4-((E)-1-(ethoxyimino)ethyl)phenyl)imino)methyl)-5-methoxyphenolato-κ2O,N)copper(II), C36H38CuN4O6
  28. Crystal structure of poly[1,2-bis(1,2,4-triazol-4-yl)ethane-κ2N:N′]silver(I) bromate monohydrate]silver(I), C6H10AgBrN6O4
  29. The crystal structure of 2,3,5-triphenyl-2,3-dihydro-1H-tetrazol-1-ium 2,3-dioxoindoline-5-sulfonate, C27H19N5O5S
  30. Crystal structure of 3-(2-amino-1,3-selenazol-4-yl)-2H-chromen-2-one – dimethylformamide (1/1), C15H15N3O3Se
  31. Crystal structure of diethyl 3,3′-(diazene-1,2-diyl)(E)-dibenzoate, C18H18N2O4
  32. Crystal structure of cis-bis((1H-benzimidazol-2-yl)methanol-κN,O)-bis(isothiocyanato-κN)nickel(II), C18H16N6NiO2S2
  33. Crystal structure of bis(2-(2′-hydroxy-5′-methoxyphenyl)-1H-benzimidazole)boron – tetrahydrofuran (1/1), C36H37N4O6B
  34. Crystal structure of poly[aqua-bis(nitrato-κ2O,O′)-(μ3-1,3-benzimidazol-3-ium-1,3-diacetato-κ4O,O′:O′′:O′′′)dysprosium(III)], C11H11DyN4O11
  35. Crystal structure of n-butyl-tris(dicyclo-hexylamido)hafnium(IV), C40H75HfN3
  36. Crystal structure of (E)-1-[1-(3-chloro-4-fluoro-phenyl)ethylidene]-2-(2,4-dinitrophenyl)hydrazine, C28H20Cl2F2N8O8
  37. The crystal structure of ethyl 4-((2-hydroxybenzyl)amino)benzoate, a Schiff base, C16H17NO3
  38. Crystal structure of 3-(2-(4-isobutylphenyl)propanoyl)-1-methylimidazolidine-2,4-dione, C17H22N2O3
  39. Crystal structure of poly[(μ3-2-(pyrazin-2-ylthio)acetato-κ3N:O:S)silver(I)], C6H5AgN2O2S
  40. Crystal structure of (E)-1-(3-((E)-((2-hydroxynaphthalen-1-yl)methylene)amino)phenyl)ethanone O-benzyl oxime, C26H22N2O2
  41. Crystal structure of (E)-2,3-dihydroxybenzaldehyde O-(2-((((E)-1-(2,5-dihydroxyphenyl)ethylidene)amino)oxy)ethyl) oxime monohydrate, C17H20N2O7
  42. Crystal structure of 4-(chloromethyl)-3-nitrobenzoic acid, C8H6ClNO4
  43. Crystal stucture of 4-((10H-phenothiazin-10-yl)methyl)-2,6-di-tert-butylphenol, C27H31NOS
  44. The crystal structure of ethyl 1-(4-nitrophenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate, C13H10F3N3O4
  45. Crystal structure of catena-poly[di-(μ3-oxido-κ3O:O:O)-tetraoxido-(μ2-5′-(pyrazin-2-yl)-1H,2′H-3,3′-bi(1,2,4-triazole)-κ2N:N′)dimolybdenum(VI)], C8H6Mo2N8O6
  46. Crystal structure of (3,6-dioxocyclohexa-1,4-diene-1,4-bis(olato)-κ4O,O′:O′′,O′′′)-bis(tris(2-pyridylmethyl)amine-κ4N,N′,N′′,N′′′))-dizinc(II) bis(hexafluorophosphate(V)), C42H38F12N8O4P2Zn2
  47. Crystal structure of catena-poly[hexakis(μ2-2-acetylphenolato-κ3O:O,O′)trimanganese(II)], C48H42Mn3O12
  48. The crystal structure of 2,2-difluoro-4-(trifluoromethyl)-2,5-dihydro-[1,3,2]dioxaborinino[5,4-c]chromen-3-ium-2-uide, C11H6BF5O3
  49. Crystal structure of methyl (E)-2-(4-(diethylamino)-2-hydroxybenzylidene)hydrazine-1-carboxylate, C13H19N3O3
  50. The crystal structure of tert-butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate, C10H15N3O2
  51. Crystal structure of 1,1-bis(η5-adamantylcyclopentadienyl)-3-phenyl-2-trimethylsilyl-2,3-dihydroisotitanazole, C42H55NSiTi
  52. Crystal structure of 2-(4-(2-(4-benzylpiperazin-1-yl)ethyl)benzyl)isoindoline-1,3-dione, C28H29N3O2
  53. Important impurity of Flupirtine – a single crystal study on ethyl (6-amino-5-((ethoxycarbonyl)amino)pyridin-2-yl)(4-fluorobenzyl)carbamate, C18H21FN4O4
  54. Crystal structure of ethyl 3-(4-methoxyphenyl)-1-(2-(4-methoxyphenyl)-2-oxoethyl)-1H-pyrazole-5-carboxylate, C22H22N2O5
  55. Crystal structure of 2,3,9,10-tetramethoxy-5,6-dihydroisoquinolino[2,1-b]isoquinolin-7-ium 5-hydroxy-3-(4-hydroxyphenyl)-4-oxo-4H-chromen-7-olate methanol solvate, C37H35N1O10
  56. The crystal structure of the inner salt of 2-[(aminoiminomethyl)amino]ethylcarbamic acid [systematic name: (2-((diaminomethylene)ammonio)ethyl)carbamate], C4H10N4O2
  57. Crystal structure of (8-hydroxy-5-nitroquinolinium) perchlorate – 8-hydroxy-5-nitroquinoline (1/1), C18H13ClN4O10
  58. The crystal structure of (5-methyl-1,2,4-oxadiazol-3-yl)ferrocene, C13H12FeN2O
  59. Crystal structure of methyl 1-(2-(fluorosulfonyl)ethyl)-2-oxocyclopentanecarboxylate, C9H13FO5S
  60. Crystal structure of the triclinic modification of 1-methyl-4-nitroimidzole, C4H5N3O2
  61. Corrigendum
  62. Crystal structure of 4-bromo-2-(1H-pyrazol-3-yl)phenol, C9H7BrN2O
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