Lomefloxacinium picrate

Jerry P Jasinski; Ray J Butcher; M S Siddegowda; H S Yathirajan; Q N M Hakim Al-arique

doi:10.1107/S1600536811002534

. 2011 Jan 26;67(Pt 2):o483–o484. doi: 10.1107/S1600536811002534

Lomefloxacinium picrate

Jerry P Jasinski ^a,^*, Ray J Butcher ^b, M S Siddegowda ^c, H S Yathirajan ^c, Q N M Hakim Al-arique ^c

PMCID: PMC3051677 PMID: 21523140

Abstract

In the cation of the title compound [systematic name: (RS)-4-(3-carboxy-1-ethyl-6,8-difluoro-4-oxo-1,4-dihydroquinolin-7-yl)-2-methylpiperazin-1-ium 2,4,6-trinitrophenolate], C₁₇H₂₀F₂N₃O₃ ⁺·C₆H₂N₃O₇ ⁻, the piperazine ring adopts a slightly distorted chair conformation and contains a protonated N atom. An intramolecular O—H⋯O hydrogen bond occurs in the cation. The dihedral angles between the mean planes of the six-atom piperazine ring and the 10-atom fused ring system is 43.3 (5)°. The picrate anion interacts with the protonated N atom of an adjacent cation through a bifurcated N—H⋯(O,O) three-center hydrogen bond. Strong N—H⋯O hydrogen bonds in concert with weak π–π stacking interactions [centroid–centroid distance = 3.6460 (14) Å] dominate the crystal packing, creating a two-dimensional network structure along [011].

Related literature

For background to lomefloxacin, see: Rubinstein et al. (2001 ▶). For related structures, see: Jasinski et al. (2009 ▶, 2010a ▶,b ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₇H₂₀F₂N₃O₃ ⁺·C₆H₂N₃O₇ ⁻
M _r = 580.47
Triclinic,
a = 10.9314 (4) Å
b = 11.6748 (4) Å
c = 12.0530 (4) Å
α = 92.969 (3)°
β = 115.555 (3)°
γ = 109.852 (3)°
V = 1269.14 (8) Å³
Z = 2
Cu Kα radiation
μ = 1.13 mm⁻¹
T = 123 K
0.44 × 0.33 × 0.19 mm

Data collection

Oxford Diffraction Xcalibur Ruby Gemini diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 ▶) T _min = 0.838, T _max = 1.000
8890 measured reflections
5002 independent reflections
4423 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.068
wR(F ²) = 0.198
S = 1.06
5002 reflections
373 parameters
H-atom parameters constrained
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis RED (Oxford Diffraction, 2007 ▶); 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.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811002534/fl2332sup1.cif

e-67-0o483-sup1.cif^{(26KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811002534/fl2332Isup2.hkl

e-67-0o483-Isup2.hkl^{(245KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O3	0.84	1.74	2.520 (3)	153
N3—H3A⋯O2ⁱ	0.92	2.09	2.984 (3)	164
N3—H3B⋯O1B	0.92	1.81	2.714 (3)	166
N3—H3B⋯O2B	0.92	2.52	2.993 (3)	113

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Symmetry code: (i) Inline graphic .

Acknowledgments

MSS thanks the University of Mysore for the research facilities and HSY thanks the UOM for sabbatical leave. RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.

supplementary crystallographic information

Comment

Lomefloxacin hydrochloride is a fluoroquinolone antibiotic used to treat bacterial infections including bronchitis and urinary tract infections. It is also used to prevent urinary tract infections prior to surgery. Lomefloxacin, chemically (RS)-1-ethyl-6,8-difluoro-7-(3-methylpiperazin- 1-yl)-4-oxo-quinoline-3-carboxylic acid, is associated with phototoxicity and adverse central nervous system adverse effects (Rubinstein et al., 2001). Recently, the crystal structures of propiverine picrate (Jasinski et al., 2009), imatinibium dipicrate (Jasinski et al., 2010a) and chlorimipraminium picrate (Jasinski et al., 2010b) have been reported. In continuation of our work on picrates of biologically active compounds, this paper reports the crystal structure of (I), obtained by the interaction of picric acid and lomefloxacin.

In the crystal structure of the title compound, there is one cation-anion pair in the asymmetric unit (Fig. 1). One N atom in the 6-membered piperazine ring (N2/C10/C11/N3/C13/C14) in the lomefloxacinium cation is protonated which adopts a slightly distorted chair conformation with puckering parameters Q, θ and φ of 0.565 (3) Å, 178.0 (3)° and 109 (58)° (Cremer & Pople, 1975). The dihedral angle between the mean planes of the piperazine ring (N2/C10/C11/N3/C13/C14) and the 10-atom ring system of the quinolone group is 43.3 (5)°. The picrate anion interacts with the protonated N atom of an adjacent cation through a bifurcated N—H···O three-center hydrogen bond. The dihedral angle between the mean planes of the anion benzene and cation piperizine and quinoline rings is 46.2 (9)° and 7.2 (2)°, respectively. The mean planes of the two o-NO₂ and single p-NO₂ groups in the picrate anion are twisted by, 37.9 (5)°, 57.0 (8)° [using predominant component (0.743 (4), O6A & O7A, of disordered O atoms] and 2.5 (1)° with respect to the mean planes of the 6-membered benzene ring. Bond distances (Allen et al., 1987) and angles are in normal ranges. Strong N—H···O hydrogen bonds in concert with weak π–π stacking interactions (Table 2) dominate the crystal packing creating a 2-D network along [011] (Fig. 2).

Experimental

Lomefloxacin hydrochloride (3.87 g, 0.01 mol) of picric acid (2.99 g, 0.01 mol) was dissolved in 15 ml of dimethyl formamide. The solution was stirred for 15 min over a heating magnetic stirrer at 335 K. The resulting solution was kept aside at room temperature. X-ray quality crystals were grown from slow evaporation of dimethyl formamide solution (m.p.: 489 – 491 K).