organic compounds
1-Cyclopropyl-6-fluoro-7-(4-nitrosopiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid
aSchool of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, People's Republic of China, and bMaterial Engineering College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, People's Republic of China
*Correspondence e-mail: ltdl@sina.com
The title compound, C17H17FN4O4, is a derivative of ciprofloxacin [1-cyclopropyl-6-fluoro-4-oxo-7-(1-piperazinyl)-1,4-dihydroquinoline-3-carboxylic acid]. The crystal packing is stabilized by intermolecular C—H⋯O hydrogen bonds together with π–π electron ring interactions [centroid–centroid separations between quinoline rings of 3.5864 (11) and 3.9339 (13) Å]. A strong intramolecular O—H⋯O hydrogen bonds is present as well as an intramolecular C—H⋯F interaction.
Related literature
For the biological activity of ciprofloxacin compounds, see: Neu (1987). For related structures, see: Turel et al. (1996); Drevenšek et al. (2003); Li et al. (2005); Lou et al. (2007). The nitroso-group geometry is similar to that observed in 1,4-dinitrosopiperazine, see: Sekido et al. (1985).
Experimental
Crystal data
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Refinement
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Data collection: CrystalClear (Rigaku, 2007); cell CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 and DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Supporting information
10.1107/S1600536809029729/fb2160sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809029729/fb2160Isup2.hkl
The title compound was hydrothermally synthesized under autogenous pressure. A mixture of C17H18FN3O3.HCl (ciprofloxacin hydrochloride) (50 mg, 0.14 mmol), Yb(NO3)3 (72 mg, 0.2 mmol), HNO3 (1 ml of 0.5 M), C2H5OH (4 ml) and H2O (8 ml) was sealed in a stainless reactor with a Teflon liner. The mixture was heated to 393 K for one day. After cooling at a rate of 10 K h-1 to room temperature, yellow needle crystals (average 4 mm long by 0.6 mm diameter) were separated by filtration, washed with distilled water and finally dried in air. Yield 75%, Anal. calc. for C17H17FN4O4: C, 56.66; H, 4.76; N, 15.55%; Found: C, 56.82; H, 4.75; N, 15.63%. IR (KBr pellet): 1719(s), 1627(s), 1489(m), 1454(m), 1334(m), 1339(m), 1257(s), 1152(m), 994(m), 896(m), 798(m), 743(m).
All the hydrogen atoms were discernible in the difference electron density maps. However, the hydrogens were situated into idealized positions and constrained by the riding model approximation: O—Hcarboxyl = 0.84 [the command AFIX 147 of SHELXL-97 has been applied (Sheldrick, 2008)], Caryl—Haryl = 0.95, Cmethylene—Hmethylene = 0.99 and Cmethine—Hmethine = 1.00 Å; UisoH = 1.2Ueq(C); UisoHcarboxyl = 1.5Ueq(O). The highest electron-density peak is situated 1.12 Å from H16A and the deepest hole 0.54 Å from C17.
Data collection: CrystalClear (Rigaku, 2007); cell
CrystalClear (Rigaku, 2007); data reduction: CrystalClear (Rigaku, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008) and DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C17H17FN4O4 | Z = 2 |
Mr = 360.35 | F(000) = 376 |
Triclinic, P1 | Dx = 1.502 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 8.378 (3) Å | Cell parameters from 771 reflections |
b = 9.625 (4) Å | θ = 2.0–27.4° |
c = 10.328 (4) Å | µ = 0.12 mm−1 |
α = 102.99 (2)° | T = 293 K |
β = 96.089 (14)° | Block, yellow |
γ = 97.392 (16)° | 0.2 × 0.2 × 0.2 mm |
V = 797.0 (6) Å3 |
Rigaku Mercury CCD/AFC diffractometer | 3631 independent reflections |
Radiation source: fine-focus sealed tube | 2568 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
ϕ and ω scans | θmax = 27.4°, θmin = 2.5° |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2007) | h = −10→10 |
Tmin = 0.976, Tmax = 0.977 | k = −12→12 |
6267 measured reflections | l = −13→11 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.067 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.207 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.1165P)2 + 0.047P] where P = (Fo2 + 2Fc2)/3 |
3631 reflections | (Δ/σ)max < 0.001 |
236 parameters | Δρmax = 0.52 e Å−3 |
0 restraints | Δρmin = −0.35 e Å−3 |
67 constraints |
C17H17FN4O4 | γ = 97.392 (16)° |
Mr = 360.35 | V = 797.0 (6) Å3 |
Triclinic, P1 | Z = 2 |
a = 8.378 (3) Å | Mo Kα radiation |
b = 9.625 (4) Å | µ = 0.12 mm−1 |
c = 10.328 (4) Å | T = 293 K |
α = 102.99 (2)° | 0.2 × 0.2 × 0.2 mm |
β = 96.089 (14)° |
Rigaku Mercury CCD/AFC diffractometer | 3631 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2007) | 2568 reflections with I > 2σ(I) |
Tmin = 0.976, Tmax = 0.977 | Rint = 0.031 |
6267 measured reflections |
R[F2 > 2σ(F2)] = 0.067 | 0 restraints |
wR(F2) = 0.207 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.52 e Å−3 |
3631 reflections | Δρmin = −0.35 e Å−3 |
236 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.14474 (19) | 0.38921 (17) | 0.16119 (15) | 0.0330 (4) | |
O2 | −0.1340 (2) | 0.09746 (18) | −0.25939 (15) | 0.0561 (5) | |
H18 | −0.0827 | 0.1674 | −0.2814 | 0.084* | |
O3 | 0.0676 (2) | 0.32428 (17) | −0.25086 (13) | 0.0472 (4) | |
C8 | 0.2117 (2) | 0.4611 (2) | −0.03990 (18) | 0.0331 (4) | |
F1 | 0.51960 (16) | 0.74426 (14) | −0.07933 (12) | 0.0505 (4) | |
C13 | 0.2335 (2) | 0.48548 (19) | 0.10118 (18) | 0.0318 (4) | |
C11 | 0.4372 (2) | 0.6987 (2) | 0.1245 (2) | 0.0342 (4) | |
C5 | 0.0120 (2) | 0.2477 (2) | −0.05450 (19) | 0.0356 (5) | |
O1 | −0.1742 (2) | 0.03235 (18) | −0.07173 (17) | 0.0580 (5) | |
C12 | 0.3415 (2) | 0.6063 (2) | 0.18211 (19) | 0.0344 (4) | |
H12A | 0.3488 | 0.6247 | 0.2770 | 0.041* | |
C9 | 0.3081 (3) | 0.5551 (2) | −0.0978 (2) | 0.0372 (5) | |
H9A | 0.2962 | 0.5415 | −0.1925 | 0.045* | |
N2 | 0.5528 (2) | 0.81427 (18) | 0.20147 (16) | 0.0380 (4) | |
C7 | 0.0944 (2) | 0.3414 (2) | −0.1242 (2) | 0.0361 (5) | |
C10 | 0.4184 (3) | 0.6654 (2) | −0.0179 (2) | 0.0361 (5) | |
C4 | 0.0408 (2) | 0.2758 (2) | 0.0830 (2) | 0.0359 (5) | |
H4A | −0.0163 | 0.2111 | 0.1257 | 0.043* | |
C6 | −0.1066 (3) | 0.1168 (2) | −0.1269 (2) | 0.0428 (5) | |
N3 | 0.7368 (3) | 1.0685 (2) | 0.37104 (18) | 0.0492 (5) | |
C3 | 0.1612 (3) | 0.4155 (2) | 0.30774 (19) | 0.0373 (5) | |
H3A | 0.1132 | 0.4997 | 0.3544 | 0.045* | |
C14 | 0.5794 (3) | 0.8301 (2) | 0.3473 (2) | 0.0473 (6) | |
H14A | 0.5869 | 0.7346 | 0.3663 | 0.057* | |
H14B | 0.4859 | 0.8666 | 0.3870 | 0.057* | |
C2 | 0.3112 (3) | 0.3878 (3) | 0.3816 (2) | 0.0512 (6) | |
H2A | 0.3549 | 0.4545 | 0.4696 | 0.061* | |
H2B | 0.3943 | 0.3493 | 0.3283 | 0.061* | |
C15 | 0.7354 (3) | 0.9344 (2) | 0.4114 (2) | 0.0487 (6) | |
H15A | 0.7434 | 0.9535 | 0.5103 | 0.058* | |
H15B | 0.8306 | 0.8901 | 0.3840 | 0.058* | |
C16 | 0.5548 (3) | 0.9558 (3) | 0.1687 (2) | 0.0570 (7) | |
H16A | 0.4633 | 1.0008 | 0.2039 | 0.068* | |
H16B | 0.5390 | 0.9417 | 0.0700 | 0.068* | |
C17 | 0.7110 (3) | 1.0550 (3) | 0.2268 (2) | 0.0574 (7) | |
H17A | 0.8022 | 1.0156 | 0.1856 | 0.069* | |
H17B | 0.7058 | 1.1509 | 0.2082 | 0.069* | |
C1 | 0.1525 (3) | 0.2910 (3) | 0.3709 (2) | 0.0551 (7) | |
H1A | 0.1379 | 0.1929 | 0.3111 | 0.066* | |
H1B | 0.0986 | 0.2981 | 0.4524 | 0.066* | |
N4 | 0.7544 (3) | 1.1903 (2) | 0.4635 (2) | 0.0654 (7) | |
O4 | 0.7463 (3) | 1.3001 (2) | 0.4211 (2) | 0.0895 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0369 (9) | 0.0264 (8) | 0.0303 (8) | −0.0042 (6) | −0.0015 (7) | 0.0040 (6) |
O2 | 0.0664 (11) | 0.0464 (10) | 0.0397 (9) | −0.0092 (8) | −0.0087 (8) | −0.0047 (7) |
O3 | 0.0588 (10) | 0.0433 (9) | 0.0306 (8) | −0.0015 (7) | −0.0052 (7) | 0.0012 (6) |
C8 | 0.0372 (10) | 0.0277 (9) | 0.0302 (10) | 0.0036 (8) | −0.0017 (8) | 0.0023 (7) |
F1 | 0.0587 (8) | 0.0475 (8) | 0.0438 (7) | −0.0084 (6) | 0.0111 (6) | 0.0155 (6) |
C13 | 0.0359 (10) | 0.0249 (9) | 0.0310 (10) | 0.0015 (8) | 0.0008 (8) | 0.0029 (7) |
C11 | 0.0373 (10) | 0.0278 (9) | 0.0340 (10) | 0.0004 (8) | −0.0015 (8) | 0.0061 (8) |
C5 | 0.0382 (10) | 0.0268 (10) | 0.0348 (11) | 0.0003 (8) | −0.0037 (8) | −0.0008 (8) |
O1 | 0.0590 (11) | 0.0456 (10) | 0.0569 (10) | −0.0192 (8) | −0.0103 (8) | 0.0103 (8) |
C12 | 0.0416 (11) | 0.0270 (9) | 0.0295 (10) | −0.0019 (8) | 0.0003 (8) | 0.0025 (7) |
C9 | 0.0455 (11) | 0.0354 (10) | 0.0293 (10) | 0.0065 (9) | 0.0029 (8) | 0.0057 (8) |
N2 | 0.0446 (10) | 0.0308 (9) | 0.0329 (9) | −0.0071 (7) | −0.0044 (7) | 0.0074 (7) |
C7 | 0.0390 (11) | 0.0306 (10) | 0.0336 (10) | 0.0058 (8) | −0.0010 (8) | −0.0002 (8) |
C10 | 0.0395 (10) | 0.0312 (10) | 0.0375 (11) | 0.0008 (8) | 0.0039 (8) | 0.0115 (8) |
C4 | 0.0361 (10) | 0.0284 (10) | 0.0380 (11) | −0.0023 (8) | −0.0013 (8) | 0.0043 (8) |
C6 | 0.0426 (11) | 0.0340 (11) | 0.0436 (12) | 0.0024 (9) | −0.0064 (9) | 0.0002 (9) |
N3 | 0.0662 (13) | 0.0354 (10) | 0.0359 (9) | −0.0088 (9) | −0.0016 (9) | 0.0013 (7) |
C3 | 0.0473 (12) | 0.0311 (10) | 0.0294 (10) | −0.0022 (8) | 0.0031 (8) | 0.0045 (8) |
C14 | 0.0608 (14) | 0.0394 (12) | 0.0337 (11) | −0.0112 (10) | −0.0030 (10) | 0.0075 (9) |
C2 | 0.0527 (14) | 0.0551 (14) | 0.0393 (12) | −0.0017 (11) | −0.0041 (10) | 0.0086 (10) |
C15 | 0.0607 (15) | 0.0401 (12) | 0.0364 (11) | −0.0056 (10) | −0.0068 (10) | 0.0051 (9) |
C16 | 0.0679 (16) | 0.0395 (13) | 0.0546 (14) | −0.0137 (11) | −0.0191 (12) | 0.0179 (11) |
C17 | 0.0767 (18) | 0.0424 (13) | 0.0451 (13) | −0.0128 (12) | −0.0004 (12) | 0.0104 (10) |
C1 | 0.0709 (16) | 0.0458 (13) | 0.0420 (12) | −0.0121 (12) | −0.0059 (11) | 0.0150 (10) |
N4 | 0.0859 (17) | 0.0430 (12) | 0.0536 (13) | −0.0081 (11) | 0.0084 (12) | −0.0059 (10) |
O4 | 0.132 (2) | 0.0383 (11) | 0.0856 (16) | 0.0046 (12) | 0.0002 (14) | 0.0002 (10) |
N1—C4 | 1.346 (2) | C4—H4A | 0.9500 |
N1—C13 | 1.405 (2) | N3—N4 | 1.315 (3) |
N1—C3 | 1.466 (2) | N3—C15 | 1.442 (3) |
O2—C6 | 1.330 (3) | N3—C17 | 1.456 (3) |
O2—H18 | 0.8400 | C3—C1 | 1.485 (3) |
O3—C7 | 1.273 (2) | C3—C2 | 1.485 (3) |
C8—C9 | 1.410 (3) | C3—H3A | 1.0000 |
C8—C13 | 1.411 (3) | C14—C15 | 1.528 (3) |
C8—C7 | 1.458 (3) | C14—H14A | 0.9900 |
F1—C10 | 1.365 (2) | C14—H14B | 0.9900 |
C13—C12 | 1.414 (3) | C2—C1 | 1.501 (3) |
C11—C12 | 1.394 (3) | C2—H2A | 0.9900 |
C11—N2 | 1.404 (2) | C2—H2B | 0.9900 |
C11—C10 | 1.420 (3) | C15—H15A | 0.9900 |
C5—C4 | 1.373 (3) | C15—H15B | 0.9900 |
C5—C7 | 1.431 (3) | C16—C17 | 1.496 (3) |
C5—C6 | 1.493 (3) | C16—H16A | 0.9900 |
O1—C6 | 1.210 (3) | C16—H16B | 0.9900 |
C12—H12A | 0.9500 | C17—H17A | 0.9900 |
C9—C10 | 1.361 (3) | C17—H17B | 0.9900 |
C9—H9A | 0.9500 | C1—H1A | 0.9900 |
N2—C14 | 1.469 (3) | C1—H1B | 0.9900 |
N2—C16 | 1.474 (3) | N4—O4 | 1.238 (3) |
C4—N1—C13 | 119.38 (16) | C1—C3—C2 | 60.70 (16) |
C4—N1—C3 | 120.52 (15) | N1—C3—H3A | 115.5 |
C13—N1—C3 | 120.07 (15) | C1—C3—H3A | 115.5 |
C6—O2—H18 | 109.5 | C2—C3—H3A | 115.5 |
C9—C8—C13 | 118.03 (17) | N2—C14—C15 | 110.91 (17) |
C9—C8—C7 | 120.60 (17) | N2—C14—H14A | 109.5 |
C13—C8—C7 | 121.36 (18) | C15—C14—H14A | 109.5 |
N1—C13—C8 | 119.20 (16) | N2—C14—H14B | 109.5 |
N1—C13—C12 | 120.02 (17) | C15—C14—H14B | 109.5 |
C8—C13—C12 | 120.77 (17) | H14A—C14—H14B | 108.0 |
C12—C11—N2 | 122.48 (18) | C3—C2—C1 | 59.64 (15) |
C12—C11—C10 | 116.46 (17) | C3—C2—H2A | 117.8 |
N2—C11—C10 | 120.98 (17) | C1—C2—H2A | 117.8 |
C4—C5—C7 | 120.37 (17) | C3—C2—H2B | 117.8 |
C4—C5—C6 | 117.68 (18) | C1—C2—H2B | 117.8 |
C7—C5—C6 | 121.95 (18) | H2A—C2—H2B | 114.9 |
C11—C12—C13 | 120.90 (18) | N3—C15—C14 | 110.6 (2) |
C11—C12—H12A | 119.6 | N3—C15—H15A | 109.5 |
C13—C12—H12A | 119.6 | C14—C15—H15A | 109.5 |
C10—C9—C8 | 119.97 (18) | N3—C15—H15B | 109.5 |
C10—C9—H9A | 120.0 | C14—C15—H15B | 109.5 |
C8—C9—H9A | 120.0 | H15A—C15—H15B | 108.1 |
C11—N2—C14 | 117.59 (15) | N2—C16—C17 | 111.9 (2) |
C11—N2—C16 | 117.81 (17) | N2—C16—H16A | 109.2 |
C14—N2—C16 | 111.17 (17) | C17—C16—H16A | 109.2 |
O3—C7—C5 | 123.16 (18) | N2—C16—H16B | 109.2 |
O3—C7—C8 | 121.43 (18) | C17—C16—H16B | 109.2 |
C5—C7—C8 | 115.41 (17) | H16A—C16—H16B | 107.9 |
C9—C10—F1 | 117.51 (17) | N3—C17—C16 | 108.62 (19) |
C9—C10—C11 | 123.63 (18) | N3—C17—H17A | 110.0 |
F1—C10—C11 | 118.81 (17) | C16—C17—H17A | 110.0 |
N1—C4—C5 | 124.20 (18) | N3—C17—H17B | 110.0 |
N1—C4—H4A | 117.9 | C16—C17—H17B | 110.0 |
C5—C4—H4A | 117.9 | H17A—C17—H17B | 108.3 |
O1—C6—O2 | 121.06 (19) | C3—C1—C2 | 59.66 (15) |
O1—C6—C5 | 123.8 (2) | C3—C1—H1A | 117.8 |
O2—C6—C5 | 115.15 (19) | C2—C1—H1A | 117.8 |
N4—N3—C15 | 119.31 (19) | C3—C1—H1B | 117.8 |
N4—N3—C17 | 125.3 (2) | C2—C1—H1B | 117.8 |
C15—N3—C17 | 115.35 (18) | H1A—C1—H1B | 114.9 |
N1—C3—C1 | 119.44 (18) | O4—N4—N3 | 115.6 (2) |
N1—C3—C2 | 119.07 (18) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H18···O3 | 0.84 | 1.78 | 2.562 (2) | 153 |
C4—H4A···O1 | 0.95 | 2.48 | 2.812 (3) | 101 |
C15—H15A···O2i | 0.99 | 2.50 | 3.405 (3) | 151 |
C15—H15B···O3ii | 0.99 | 2.51 | 3.385 (3) | 147 |
C16—H16A···O1iii | 0.99 | 2.60 | 3.264 (3) | 125 |
C16—H16B···F1 | 0.99 | 2.14 | 2.852 (3) | 128 |
C17—H17B···O4 | 0.99 | 2.30 | 2.692 (3) | 102 |
Symmetry codes: (i) x+1, y+1, z+1; (ii) −x+1, −y+1, −z; (iii) −x, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C17H17FN4O4 |
Mr | 360.35 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 8.378 (3), 9.625 (4), 10.328 (4) |
α, β, γ (°) | 102.99 (2), 96.089 (14), 97.392 (16) |
V (Å3) | 797.0 (6) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.12 |
Crystal size (mm) | 0.2 × 0.2 × 0.2 |
Data collection | |
Diffractometer | Rigaku Mercury CCD/AFC diffractometer |
Absorption correction | Multi-scan (CrystalClear; Rigaku, 2007) |
Tmin, Tmax | 0.976, 0.977 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6267, 3631, 2568 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.648 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.067, 0.207, 1.06 |
No. of reflections | 3631 |
No. of parameters | 236 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.52, −0.35 |
Computer programs: CrystalClear (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and DIAMOND (Brandenburg, 2005), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H18···O3 | 0.84 | 1.78 | 2.562 (2) | 153.4 |
C4—H4A···O1 | 0.95 | 2.48 | 2.812 (3) | 100.7 |
C15—H15A···O2i | 0.99 | 2.50 | 3.405 (3) | 151.3 |
C15—H15B···O3ii | 0.99 | 2.51 | 3.385 (3) | 147.1 |
C16—H16A···O1iii | 0.99 | 2.60 | 3.264 (3) | 124.8 |
C16—H16B···F1 | 0.99 | 2.14 | 2.852 (3) | 127.7 |
C17—H17B···O4 | 0.99 | 2.30 | 2.692 (3) | 102.1 |
Symmetry codes: (i) x+1, y+1, z+1; (ii) −x+1, −y+1, −z; (iii) −x, −y+1, −z. |
Acknowledgements
The work was supported by a grant from the National Science Foundation of China (30771682).
References
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Ciprofloxacin (1-cyclopropyl-6-fluoro -1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid) is used as an antibacterial agent. Ciprofloxacin is widely used in clinical practice for the treatment of certain diseases caused by some Gram negative and as well as Gram positive microorganisms (Neu, 1987). Recently, several structures containing ciprofloxacin have been reported (Turel et al., 1996; Drevenšek et al., 2003; Lou et al., 2007).
Nitrosation of amines by nitrites takes place in acid medium. The nature of the product depends on the nature of the initial amine. Commonly the secondary alkyl amines yield N-nitrosoamines. In our case, the N-nitrosation of ciprofloxacin occurs by ytterbium nitrate in nitric acid and results in the formation of ON-ciprofloxacin under hydrothermal reaction.
The title compound is composed of an essentially planar quinoline ring system [the mean deviation from best plane is 0.0274 (2) Å] which is substituted with cyclopropyl, fluoro, oxo, carboxyl and nitrosopiperazinium groups (Fig. 1). The bond distances and angles are in agreement with those in 1-cyclopropyl-6-fluoro-7- (4-formylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (Li et al., 2005).
In the title structure, the six-membered piperazinyl ring adopts a chair conformation. The nitroso-group geometry with the NO distance equal to 1.2382 (31) Å and O—N—N bond angle of 115.583 (20)° is similar to that observed in 1,4-dinitrosopiperazine (Sekido et al., 1985).
For the hydrogen bonding, please see Tab. 1 that comprises intramolecular and intermolecular hydrogen bonds in the structure (Fig. 2). As shown in Fig. 3, the crystal packing is stabilized by π-π stacking interactions of the quinoline rings, in which the N1 ring (N1/C4—C6/C7—C13) stacks with the inversion-related N1 rings, with the centroid-centroid separations of 3.5864 (11) and 3.9339 (13) Å.