Norfloxacin dihydrate

The antibiotic norfloxacin recrystallizes from aceto­nitrile as a dihydrate with the norfloxacin mol­ecule in a zwitterionic form, i.e. 1-ethyl-6-fluoro-1,4-di­hydro-4-oxo-7-(1-piperazin-4-io)-3-quinoline­carboxyl­ate dihydrate, C₁₆­H₁₈­F­N₃­O₃·­2H₂O.

Computing details

Data collection: MSC/Rigaku Diffractometer Control (Molecular Structure Corporation, 1985); cell refinement: MSC/Rigaku Diffractometer Control; data reduction: TEXSAN (Molecular Structure Corporation, 1993); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1994); software used to prepare material for publication: SHELXL97.

1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7(1-piperzinyl)-3-quinolinecarboxylic acid

Crystal data

C16H18FN3O3·2H2O	F(000) = 752
Mr = 355.37	Dx = 1.478 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 8.265 (3) Å	Cell parameters from 18 reflections
b = 21.698 (4) Å	θ = 9.2–12.0°
c = 9.5250 (17) Å	µ = 0.12 mm^−1
β = 110.794 (19)°	T = 123 K
V = 1596.9 (6) Å^3	Tabular, colourless
Z = 4	0.40 × 0.30 × 0.15 mm

Data collection

Rigaku AFC7S diffractometer	Rint = 0.058
Radiation source: fine-focus sealed tube	θmax = 27.5°, θmin = 2.6°
Graphite monochromator	h = 0→10
ω/2θ scans	k = 0→28
3918 measured reflections	l = −12→11
3676 independent reflections	3 standard reflections every 150 reflections
1701 reflections with I > 2σ(I)	intensity decay: 1.7%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.168	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	Calculated w = 1/[σ^2(Fo^2) + (0.0782P)^2] where P = (Fo^2 + 2Fc^2)/3
3676 reflections	(Δ/σ)max < 0.001
251 parameters	Δρmax = 0.37 e Å^−3
0 restraints	Δρmin = −0.32 e Å^−3

Special details

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.

H atoms on O and N were refined isotropically. All other H atoms were placed in calculated positions and in a riding mode.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
F1	−0.1855 (2)	0.00803 (8)	0.5884 (2)	0.0201 (5)
O1	0.4995 (4)	−0.14193 (11)	1.3917 (3)	0.0291 (6)
O2	0.3427 (3)	−0.20785 (10)	1.2160 (3)	0.0175 (5)
O3	0.0763 (3)	−0.14837 (10)	0.9802 (3)	0.0188 (5)
O4	0.5523 (3)	0.20095 (12)	1.0520 (3)	0.0245 (6)
O5	0.2650 (3)	0.22229 (14)	0.4583 (3)	0.0252 (6)
N1	0.3804 (3)	0.00629 (12)	1.1158 (3)	0.0137 (6)
N2	0.0045 (4)	0.11643 (11)	0.6723 (3)	0.0136 (6)
N3	−0.0451 (4)	0.22589 (12)	0.4946 (3)	0.0140 (6)
C1	0.4158 (4)	−0.04593 (14)	1.1983 (4)	0.0146 (7)
H1	0.5090	−0.0451	1.2887	0.018*
C2	0.3249 (4)	−0.10050 (14)	1.1592 (4)	0.0139 (7)
C3	0.3928 (4)	−0.15402 (15)	1.2637 (4)	0.0157 (7)
C4	0.1743 (4)	−0.10302 (14)	1.0238 (4)	0.0134 (7)
C5	0.1392 (4)	−0.04578 (14)	0.9351 (3)	0.0119 (7)
C6	−0.0015 (4)	−0.04432 (14)	0.7986 (4)	0.0141 (7)
H6	−0.0684	−0.0795	0.7648	0.017*
C7	−0.0404 (4)	0.00792 (15)	0.7158 (3)	0.0140 (7)
C8	0.0572 (4)	0.06269 (14)	0.7571 (4)	0.0133 (7)
C9	0.1995 (4)	0.06069 (14)	0.8910 (3)	0.0132 (7)
H9	0.2694	0.0954	0.9215	0.016*
C10	0.2396 (4)	0.00757 (14)	0.9807 (3)	0.0125 (7)
C11	−0.0228 (5)	0.11325 (14)	0.5115 (4)	0.0166 (7)
H11A	−0.0794	0.0748	0.4701	0.020*
H11B	0.0880	0.1145	0.4977	0.020*
C12	−0.1338 (5)	0.16706 (14)	0.4297 (4)	0.0175 (7)
H12A	−0.1514	0.1651	0.3235	0.021*
H12B	−0.2461	0.1652	0.4405	0.021*
C13	−0.0096 (4)	0.22847 (15)	0.6587 (4)	0.0164 (7)
H13A	−0.1184	0.2300	0.6759	0.020*
H13B	0.0541	0.2658	0.6996	0.020*
C14	0.0934 (4)	0.17335 (14)	0.7391 (4)	0.0147 (7)
H14A	0.2075	0.1742	0.7318	0.018*
H14B	0.1074	0.1749	0.8445	0.018*
C15	0.4885 (4)	0.06167 (14)	1.1738 (4)	0.0155 (7)
H15A	0.5117	0.0815	1.0916	0.019*
H15B	0.5985	0.0489	1.2472	0.019*
C16	0.4054 (5)	0.10789 (16)	1.2456 (4)	0.0215 (8)
H16A	0.2938	0.1193	1.1753	0.026*
H16B	0.4773	0.1439	1.2742	0.026*
H16C	0.3922	0.0899	1.3330	0.026*
H17	0.051 (6)	0.2282 (19)	0.464 (5)	0.045 (13)*
H18	−0.096 (6)	0.261 (2)	0.453 (5)	0.042 (13)*
H19	0.584 (5)	0.2274 (18)	1.121 (5)	0.025 (11)*
H20	0.609 (6)	0.2049 (17)	0.987 (5)	0.032 (12)*
H21	0.328 (5)	0.1955 (17)	0.500 (4)	0.013 (10)*
H22	0.322 (6)	0.254 (2)	0.463 (5)	0.047 (15)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
F1	0.0188 (11)	0.0180 (10)	0.0162 (10)	−0.0028 (8)	−0.0029 (9)	0.0011 (8)
O1	0.0401 (16)	0.0170 (13)	0.0165 (13)	0.0045 (12)	−0.0067 (12)	0.0020 (10)
O2	0.0195 (12)	0.0117 (11)	0.0200 (12)	0.0001 (10)	0.0057 (10)	0.0018 (9)
O3	0.0205 (13)	0.0112 (11)	0.0196 (13)	−0.0018 (10)	0.0011 (10)	0.0002 (10)
O4	0.0267 (15)	0.0199 (14)	0.0295 (16)	−0.0034 (11)	0.0130 (13)	−0.0071 (12)
O5	0.0158 (13)	0.0232 (15)	0.0340 (16)	0.0051 (12)	0.0058 (12)	0.0122 (13)
N1	0.0123 (14)	0.0132 (14)	0.0127 (14)	−0.0029 (11)	0.0009 (11)	−0.0014 (11)
N2	0.0181 (15)	0.0077 (13)	0.0131 (14)	−0.0015 (11)	0.0035 (12)	−0.0020 (11)
N3	0.0161 (15)	0.0100 (14)	0.0155 (14)	0.0014 (12)	0.0051 (12)	0.0027 (12)
C1	0.0162 (17)	0.0136 (16)	0.0114 (16)	0.0011 (13)	0.0017 (14)	0.0008 (12)
C2	0.0151 (16)	0.0133 (16)	0.0146 (17)	0.0037 (13)	0.0068 (14)	0.0002 (13)
C3	0.0188 (18)	0.0141 (17)	0.0168 (18)	0.0036 (13)	0.0093 (15)	0.0020 (13)
C4	0.0135 (16)	0.0127 (16)	0.0148 (17)	0.0036 (13)	0.0060 (14)	−0.0004 (13)
C5	0.0097 (16)	0.0114 (15)	0.0148 (17)	0.0004 (12)	0.0046 (14)	−0.0001 (12)
C6	0.0126 (16)	0.0128 (16)	0.0179 (18)	−0.0002 (13)	0.0065 (14)	−0.0021 (13)
C7	0.0095 (16)	0.0177 (17)	0.0117 (16)	−0.0007 (13)	0.0002 (13)	−0.0034 (13)
C8	0.0146 (17)	0.0133 (16)	0.0140 (16)	0.0009 (12)	0.0077 (14)	0.0004 (12)
C9	0.0149 (17)	0.0114 (15)	0.0126 (17)	−0.0048 (13)	0.0039 (14)	−0.0017 (12)
C10	0.0104 (16)	0.0135 (16)	0.0144 (16)	0.0008 (12)	0.0053 (13)	−0.0009 (13)
C11	0.0233 (18)	0.0121 (16)	0.0125 (16)	−0.0024 (14)	0.0039 (14)	0.0005 (13)
C12	0.0205 (17)	0.0183 (17)	0.0102 (16)	−0.0039 (14)	0.0011 (14)	0.0000 (13)
C13	0.0195 (18)	0.0109 (16)	0.0184 (18)	0.0012 (13)	0.0063 (15)	−0.0005 (13)
C14	0.0189 (17)	0.0092 (15)	0.0133 (16)	−0.0018 (13)	0.0026 (14)	0.0007 (13)
C15	0.0146 (17)	0.0117 (16)	0.0183 (17)	−0.0033 (13)	0.0032 (15)	0.0030 (13)
C16	0.0209 (18)	0.0217 (19)	0.0203 (19)	−0.0062 (15)	0.0052 (15)	−0.0042 (15)

Geometric parameters (Å, º)

F1—C7	1.370 (4)	C2—C4	1.441 (5)
O1—C3	1.253 (4)	C2—C3	1.502 (4)
O2—C3	1.268 (4)	C4—C5	1.472 (4)
O3—C4	1.248 (4)	C5—C10	1.401 (4)
N1—C1	1.350 (4)	C5—C6	1.404 (4)
N1—C10	1.396 (4)	C6—C7	1.353 (4)
N1—C15	1.482 (4)	C7—C8	1.412 (4)
N2—C8	1.397 (4)	C8—C9	1.396 (4)
N2—C14	1.462 (4)	C9—C10	1.402 (4)
N2—C11	1.469 (4)	C11—C12	1.518 (4)
N3—C13	1.486 (4)	C13—C14	1.510 (4)
N3—C12	1.492 (4)	C15—C16	1.510 (5)
C1—C2	1.380 (4)
C1—N1—C10	119.4 (3)	C10—C5—C4	123.0 (3)
C1—N1—C15	119.1 (3)	C6—C5—C4	118.7 (3)
C10—N1—C15	121.5 (3)	C7—C6—C5	120.4 (3)
C8—N2—C14	116.6 (3)	C6—C7—F1	118.0 (3)
C8—N2—C11	117.7 (2)	C6—C7—C8	123.3 (3)
C14—N2—C11	111.1 (2)	F1—C7—C8	118.6 (3)
C13—N3—C12	110.7 (3)	C9—C8—N2	122.9 (3)
N1—C1—C2	125.3 (3)	C9—C8—C7	116.2 (3)
C1—C2—C4	119.2 (3)	N2—C8—C7	120.8 (3)
C1—C2—C3	116.4 (3)	C8—C9—C10	121.5 (3)
C4—C2—C3	124.3 (3)	N1—C10—C5	118.5 (3)
O1—C3—O2	124.7 (3)	N1—C10—C9	121.1 (3)
O1—C3—C2	116.8 (3)	C5—C10—C9	120.3 (3)
O2—C3—C2	118.5 (3)	N2—C11—C12	109.9 (3)
O3—C4—C2	125.5 (3)	N3—C12—C11	109.1 (3)
O3—C4—C5	120.1 (3)	N3—C13—C14	111.6 (3)
C2—C4—C5	114.4 (3)	N2—C14—C13	110.1 (3)
C10—C5—C6	118.2 (3)	N1—C15—C16	113.4 (3)
C10—N1—C1—C2	1.3 (5)	F1—C7—C8—C9	177.4 (3)
C15—N1—C1—C2	179.1 (3)	C6—C7—C8—N2	−175.8 (3)
N1—C1—C2—C4	−3.1 (5)	F1—C7—C8—N2	1.8 (4)
N1—C1—C2—C3	176.7 (3)	N2—C8—C9—C10	174.0 (3)
C1—C2—C3—O1	15.5 (4)	C7—C8—C9—C10	−1.6 (5)
C4—C2—C3—O1	−164.7 (3)	C1—N1—C10—C5	0.0 (4)
C1—C2—C3—O2	−162.6 (3)	C15—N1—C10—C5	−177.7 (3)
C4—C2—C3—O2	17.2 (5)	C1—N1—C10—C9	−179.4 (3)
C1—C2—C4—O3	−176.1 (3)	C15—N1—C10—C9	2.9 (5)
C3—C2—C4—O3	4.0 (5)	C6—C5—C10—N1	−179.5 (3)
C1—C2—C4—C5	3.3 (4)	C4—C5—C10—N1	0.6 (4)
C3—C2—C4—C5	−176.5 (3)	C6—C5—C10—C9	−0.2 (4)
O3—C4—C5—C10	177.3 (3)	C4—C5—C10—C9	179.9 (3)
C2—C4—C5—C10	−2.2 (4)	C8—C9—C10—N1	−178.9 (3)
O3—C4—C5—C6	−2.6 (4)	C8—C9—C10—C5	1.7 (5)
C2—C4—C5—C6	177.9 (3)	C8—N2—C11—C12	161.2 (3)
C10—C5—C6—C7	−1.5 (5)	C14—N2—C11—C12	−60.6 (3)
C4—C5—C6—C7	178.4 (3)	C13—N3—C12—C11	−56.9 (4)
C5—C6—C7—F1	−175.9 (3)	N2—C11—C12—N3	59.3 (3)
C5—C6—C7—C8	1.7 (5)	C12—N3—C13—C14	55.6 (4)
C14—N2—C8—C9	−7.0 (4)	C8—N2—C14—C13	−163.4 (3)
C11—N2—C8—C9	128.9 (3)	C11—N2—C14—C13	57.9 (3)
C14—N2—C8—C7	168.3 (3)	N3—C13—C14—N2	−55.3 (4)
C11—N2—C8—C7	−55.7 (4)	C1—N1—C15—C16	−100.1 (4)
C6—C7—C8—C9	−0.1 (5)	C10—N1—C15—C16	77.7 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H17···O5	0.94 (5)	1.79 (5)	2.706 (4)	163 (4)
N3—H18···O2^i	0.89 (4)	2.21 (5)	2.939 (4)	139 (4)
N3—H18···O3^i	0.89 (4)	2.06 (4)	2.759 (4)	135 (4)
O4—H19···O2^ii	0.84 (4)	2.02 (4)	2.862 (4)	179 (4)
O4—H20···O2^iii	0.90 (5)	2.11 (5)	2.977 (4)	161 (4)
O5—H21···O1^iii	0.79 (4)	1.84 (4)	2.626 (4)	171 (4)
O5—H22···O4^iv	0.83 (5)	2.04 (5)	2.776 (4)	149 (4)
C13—H13A···O2^v	0.97	2.47	3.397 (5)	161
C13—H13B···O5^vi	0.97	2.48	3.136 (5)	125
C13—H13B···O3^i	0.97	2.50	2.946 (4)	108

Symmetry codes: (i) −x, y+1/2, −z+3/2; (ii) −x+1, y+1/2, −z+5/2; (iii) −x+1, −y, −z+2; (iv) x, −y+1/2, z−1/2; (v) −x, −y, −z+2; (vi) x, −y+1/2, z+1/2.