organic compounds
4-Ethoxyimino-N′-methoxypyrrolidin-1-ium-3-carboximidamidium dichloride
aInstitute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, and Peking Union Medical College, Beijing 100050, People's Republic of China
*Correspondence e-mail: lmllyx@yahoo.com.cn
The title compound, C8H18N4O22+·2Cl−, contains two oxime groups. The methyl oxime group has a Z configuration, and the ethyl oxime group is disordered, with both Z and E configurations in occupancies of 0.840 (8) and 0.160 (8), respectively. In the there are a number of N—H⋯Cl hydrogen bonds.
Related literature
For properties of quinolone derivatives, see: Ball et al. (1998); Ray et al. (2005). For the synthesis of new quinolones, see: Anderson & Osheroff (2001); Choi et al. (2004); Wang, Guo et al. (2008). For some crystal structures of quinolones, see: Wang, Liu et al. (2008).
Experimental
Crystal data
|
Refinement
|
Data collection: SMART (Bruker, 1998); cell SAINT (Bruker, 1999); data reduction: SAINT and SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536809004772/pk2146sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809004772/pk2146Isup2.hkl
To a stirring solution of N'-methoxy-(1-N-tert-butoxycarbonyl-4- ethoxyimino) pyrrolidine-3-carboximidamide (15.0 g, 50.0 mmol) in methanol (80 ml) was pumped into dry hydrogen chloride for 2 h at room temperature. After the removal of the methanol under reduced pressure, the residue was treated with ethyl acetate (80 ml), and filtered. The filter cake was washed with ethyl acetate and ether, respectively, dried in vacuo to give the title compound as a white solid (11.5 g, 84.2%; mp: 375–376 K). Single crystals suitable for X-ray analysis were obtained by slow evaporation of a methanol/ ethyl acetate (1:1 v/v). 1H NMR(DMSO-d6, δ):1.14–1.17(3H, m, CH3), 3.44–3.58(m, 1H, pyrrolidine), 3.53(2H, br, NH2+), 3.66(3H, s, OCH3), 3.68–3.79(2H, m, OCH2), 4.03–4.11(4H, m, pyrrolidine), 9.88–9.93(3H, br, NH2, NH+). MS(ESI, m/z): 201(M+H)+.
All H atoms were placed at calculated positions, with C—H = 0.96–0.97 Å, N—H= 0.86–0.90 Å, and included in the final cycles of
using a riding model, with Uiso(H) = 1.2Ueq(C, N) or 1.5Ueq(C) for methyl H atoms.Data collection: SMART (Bruker, 1998); cell
SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999) and SHELXTL (Sheldrick, 2008); 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 (Sheldrick, 2008).Fig. 1. The molecular structure showing 40% probability displacement ellipsoids and the atom-numbering scheme. | |
Fig. 2. Crystal packing of the title compound viewed down the b axis. |
C8H18N4O22+·2Cl− | F(000) = 1152 |
Mr = 273.16 | Dx = 1.223 Mg m−3 |
Orthorhombic, Pbcn | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P2n 2ab | Cell parameters from 3944 reflections |
a = 12.7355 (14) Å | θ = 2.2–24.1° |
b = 8.8506 (12) Å | µ = 0.43 mm−1 |
c = 26.334 (2) Å | T = 298 K |
V = 2968.3 (6) Å3 | Block, colorless |
Z = 8 | 0.23 × 0.20 × 0.19 mm |
Bruker SMART CCD area-detector diffractometer | 2597 independent reflections |
Radiation source: fine-focus sealed tube | 1986 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.062 |
ϕ and ω scans | θmax = 25.0°, θmin = 1.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −15→14 |
Tmin = 0.907, Tmax = 0.922 | k = −10→10 |
14370 measured reflections | l = −29→31 |
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)] = 0.077 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.210 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0819P)2 + 7.7771P] where P = (Fo2 + 2Fc2)/3 |
2597 reflections | (Δ/σ)max = 0.001 |
170 parameters | Δρmax = 0.44 e Å−3 |
0 restraints | Δρmin = −0.33 e Å−3 |
C8H18N4O22+·2Cl− | V = 2968.3 (6) Å3 |
Mr = 273.16 | Z = 8 |
Orthorhombic, Pbcn | Mo Kα radiation |
a = 12.7355 (14) Å | µ = 0.43 mm−1 |
b = 8.8506 (12) Å | T = 298 K |
c = 26.334 (2) Å | 0.23 × 0.20 × 0.19 mm |
Bruker SMART CCD area-detector diffractometer | 2597 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1986 reflections with I > 2σ(I) |
Tmin = 0.907, Tmax = 0.922 | Rint = 0.062 |
14370 measured reflections |
R[F2 > 2σ(F2)] = 0.077 | 0 restraints |
wR(F2) = 0.210 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.44 e Å−3 |
2597 reflections | Δρmin = −0.33 e Å−3 |
170 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 | Occ. (<1) | |
Cl1 | 0.67028 (9) | 0.08761 (14) | 0.52171 (5) | 0.0516 (4) | |
Cl2 | 0.18814 (10) | 0.22720 (17) | 0.63480 (6) | 0.0636 (5) | |
N1 | 0.3711 (3) | 0.1103 (5) | 0.57222 (17) | 0.0528 (11) | |
H1A | 0.3640 | 0.0382 | 0.5484 | 0.063* | |
H1B | 0.3090 | 0.1220 | 0.5881 | 0.063* | |
N2 | 0.5131 (3) | 0.5960 (4) | 0.59228 (17) | 0.0543 (11) | |
H2 | 0.4590 | 0.6173 | 0.6105 | 0.065* | |
N3 | 0.6142 (3) | 0.4217 (5) | 0.55190 (18) | 0.0573 (12) | |
H3A | 0.6593 | 0.4897 | 0.5437 | 0.069* | |
H3B | 0.6239 | 0.3293 | 0.5429 | 0.069* | |
N4 | 0.559 (2) | 0.2442 (19) | 0.6611 (11) | 0.065 (4) | 0.840 (8) |
N4' | 0.570 (12) | 0.212 (14) | 0.657 (6) | 0.065 (4) | 0.160 (8) |
O1 | 0.5835 (3) | 0.7083 (4) | 0.57752 (15) | 0.0579 (10) | |
O2 | 0.5905 (4) | 0.1079 (6) | 0.6834 (2) | 0.0762 (17) | 0.840 (8) |
O2' | 0.581 (2) | 0.352 (3) | 0.6806 (10) | 0.071 (8) | 0.160 (8) |
C1 | 0.4045 (4) | 0.2533 (6) | 0.5489 (2) | 0.0503 (12) | |
H1C | 0.3451 | 0.3066 | 0.5343 | 0.060* | |
H1D | 0.4564 | 0.2359 | 0.5226 | 0.060* | |
C2 | 0.4513 (4) | 0.3417 (5) | 0.59299 (19) | 0.0446 (11) | |
H2A | 0.3944 | 0.3920 | 0.6115 | 0.053* | |
C3 | 0.4953 (4) | 0.2171 (5) | 0.62580 (18) | 0.0454 (11) | |
C4 | 0.4533 (4) | 0.0679 (6) | 0.6089 (2) | 0.0545 (13) | |
H4A | 0.5075 | 0.0076 | 0.5929 | 0.065* | |
H4B | 0.4240 | 0.0119 | 0.6372 | 0.065* | |
C5 | 0.5316 (4) | 0.4584 (5) | 0.57781 (19) | 0.0443 (11) | |
C6 | 0.6473 (6) | 0.7496 (7) | 0.6196 (3) | 0.0761 (18) | |
H6A | 0.6036 | 0.7852 | 0.6468 | 0.091* | |
H6B | 0.6949 | 0.8283 | 0.6096 | 0.091* | |
H6C | 0.6866 | 0.6633 | 0.6309 | 0.091* | |
C7 | 0.6511 (8) | 0.1432 (11) | 0.7286 (3) | 0.089 (3) | 0.840 (8) |
H7A | 0.6104 | 0.2054 | 0.7517 | 0.106* | 0.840 (8) |
H7B | 0.7149 | 0.1970 | 0.7197 | 0.106* | 0.840 (8) |
C8 | 0.6770 (12) | −0.0062 (15) | 0.7528 (5) | 0.142 (5) | 0.840 (8) |
H8A | 0.6131 | −0.0580 | 0.7613 | 0.171* | 0.840 (8) |
H8B | 0.7174 | 0.0105 | 0.7830 | 0.171* | 0.840 (8) |
H8C | 0.7169 | −0.0665 | 0.7294 | 0.171* | 0.840 (8) |
C7' | 0.648 (4) | 0.337 (6) | 0.7247 (18) | 0.089 (3) | 0.160 (8) |
H7'1 | 0.6934 | 0.2488 | 0.7214 | 0.106* | 0.160 (8) |
H7'2 | 0.6072 | 0.3274 | 0.7555 | 0.106* | 0.160 (8) |
C8' | 0.713 (6) | 0.482 (7) | 0.725 (2) | 0.12 (2) | 0.160 (8) |
H8'1 | 0.7592 | 0.4822 | 0.7541 | 0.148* | 0.160 (8) |
H8'2 | 0.6673 | 0.5680 | 0.7270 | 0.148* | 0.160 (8) |
H8'3 | 0.7545 | 0.4884 | 0.6947 | 0.148* | 0.160 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0413 (7) | 0.0468 (7) | 0.0667 (8) | 0.0032 (5) | −0.0018 (6) | −0.0150 (6) |
Cl2 | 0.0396 (7) | 0.0652 (9) | 0.0862 (10) | −0.0009 (6) | 0.0023 (6) | −0.0207 (8) |
N1 | 0.040 (2) | 0.053 (3) | 0.065 (3) | −0.010 (2) | 0.003 (2) | −0.020 (2) |
N2 | 0.049 (2) | 0.039 (2) | 0.074 (3) | −0.002 (2) | 0.011 (2) | −0.006 (2) |
N3 | 0.044 (2) | 0.038 (2) | 0.090 (3) | −0.0026 (19) | 0.018 (2) | −0.007 (2) |
N4 | 0.067 (7) | 0.060 (11) | 0.068 (6) | −0.008 (7) | −0.015 (5) | 0.001 (8) |
N4' | 0.067 (7) | 0.060 (11) | 0.068 (6) | −0.008 (7) | −0.015 (5) | 0.001 (8) |
O1 | 0.058 (2) | 0.0403 (19) | 0.076 (3) | −0.0096 (17) | 0.011 (2) | 0.0023 (18) |
O2 | 0.086 (4) | 0.065 (3) | 0.077 (3) | −0.009 (3) | −0.027 (3) | 0.008 (3) |
O2' | 0.078 (18) | 0.065 (18) | 0.072 (17) | −0.006 (14) | −0.016 (14) | −0.016 (15) |
C1 | 0.035 (2) | 0.059 (3) | 0.057 (3) | 0.002 (2) | −0.005 (2) | −0.004 (2) |
C2 | 0.036 (2) | 0.040 (3) | 0.058 (3) | −0.001 (2) | 0.005 (2) | −0.002 (2) |
C3 | 0.040 (3) | 0.049 (3) | 0.047 (3) | −0.009 (2) | −0.004 (2) | 0.000 (2) |
C4 | 0.049 (3) | 0.046 (3) | 0.068 (3) | −0.004 (2) | 0.000 (3) | −0.002 (3) |
C5 | 0.036 (2) | 0.041 (3) | 0.056 (3) | 0.004 (2) | −0.001 (2) | −0.004 (2) |
C6 | 0.070 (4) | 0.065 (4) | 0.093 (5) | −0.016 (3) | 0.007 (4) | −0.014 (3) |
C7 | 0.094 (6) | 0.090 (6) | 0.082 (5) | 0.004 (5) | −0.034 (5) | 0.001 (5) |
C8 | 0.177 (14) | 0.139 (10) | 0.110 (9) | 0.045 (9) | −0.059 (9) | 0.010 (8) |
C7' | 0.094 (6) | 0.090 (6) | 0.082 (5) | 0.004 (5) | −0.034 (5) | 0.001 (5) |
C8' | 0.14 (5) | 0.13 (5) | 0.10 (4) | 0.01 (4) | −0.02 (4) | −0.03 (4) |
N1—C1 | 1.470 (7) | C2—C3 | 1.509 (7) |
N1—C4 | 1.473 (7) | C2—H2A | 0.9800 |
N1—H1A | 0.9000 | C3—C4 | 1.493 (7) |
N1—H1B | 0.9000 | C4—H4A | 0.9700 |
N2—C5 | 1.297 (6) | C4—H4B | 0.9700 |
N2—O1 | 1.393 (5) | C6—H6A | 0.9600 |
N2—H2 | 0.8600 | C6—H6B | 0.9600 |
N3—C5 | 1.296 (6) | C6—H6C | 0.9600 |
N3—H3A | 0.8600 | C7—C8 | 1.504 (14) |
N3—H3B | 0.8600 | C7—H7A | 0.9700 |
N4—C3 | 1.26 (3) | C7—H7B | 0.9700 |
N4—O2 | 1.40 (2) | C8—H8A | 0.9600 |
N4'—C3 | 1.26 (16) | C8—H8B | 0.9600 |
N4'—O2' | 1.39 (12) | C8—H8C | 0.9600 |
O1—C6 | 1.423 (8) | C7'—C8' | 1.53 (8) |
O2—C7 | 1.454 (9) | C7'—H7'1 | 0.9700 |
O2'—C7' | 1.45 (5) | C7'—H7'2 | 0.9700 |
C1—C2 | 1.521 (7) | C8'—H8'1 | 0.9600 |
C1—H1C | 0.9700 | C8'—H8'2 | 0.9600 |
C1—H1D | 0.9700 | C8'—H8'3 | 0.9600 |
C2—C5 | 1.507 (7) | ||
C1—N1—C4 | 106.7 (4) | N1—C4—H4B | 111.2 |
C1—N1—H1A | 110.4 | C3—C4—H4B | 111.2 |
C4—N1—H1A | 110.4 | H4A—C4—H4B | 109.1 |
C1—N1—H1B | 110.4 | N3—C5—N2 | 122.5 (5) |
C4—N1—H1B | 110.4 | N3—C5—C2 | 121.2 (4) |
H1A—N1—H1B | 108.6 | N2—C5—C2 | 116.3 (4) |
C5—N2—O1 | 118.1 (4) | O1—C6—H6A | 109.5 |
C5—N2—H2 | 120.9 | O1—C6—H6B | 109.5 |
O1—N2—H2 | 120.9 | H6A—C6—H6B | 109.5 |
C5—N3—H3A | 120.0 | O1—C6—H6C | 109.5 |
C5—N3—H3B | 120.0 | H6A—C6—H6C | 109.5 |
H3A—N3—H3B | 120.0 | H6B—C6—H6C | 109.5 |
C3—N4—O2 | 109.2 (14) | O2—C7—C8 | 105.9 (8) |
C3—N4'—O2' | 109 (9) | O2—C7—H7A | 110.6 |
N2—O1—C6 | 109.5 (4) | C8—C7—H7A | 110.6 |
N4—O2—C7 | 108.0 (11) | O2—C7—H7B | 110.6 |
N4'—O2'—C7' | 109 (7) | C8—C7—H7B | 110.6 |
N1—C1—C2 | 103.8 (4) | H7A—C7—H7B | 108.7 |
N1—C1—H1C | 111.0 | C7—C8—H8A | 109.5 |
C2—C1—H1C | 111.0 | C7—C8—H8B | 109.5 |
N1—C1—H1D | 111.0 | H8A—C8—H8B | 109.5 |
C2—C1—H1D | 111.0 | C7—C8—H8C | 109.5 |
H1C—C1—H1D | 109.0 | H8A—C8—H8C | 109.5 |
C5—C2—C3 | 113.7 (4) | H8B—C8—H8C | 109.5 |
C5—C2—C1 | 114.6 (4) | O2'—C7'—C8' | 104 (4) |
C3—C2—C1 | 101.9 (4) | O2'—C7'—H7'1 | 110.9 |
C5—C2—H2A | 108.8 | C8'—C7'—H7'1 | 110.9 |
C3—C2—H2A | 108.8 | O2'—C7'—H7'2 | 110.9 |
C1—C2—H2A | 108.8 | C8'—C7'—H7'2 | 110.9 |
N4—C3—C4 | 128.4 (10) | H7'1—C7'—H7'2 | 108.9 |
N4'—C3—C4 | 116 (6) | C7'—C8'—H8'1 | 109.5 |
N4—C3—C2 | 121.6 (10) | C7'—C8'—H8'2 | 109.5 |
N4'—C3—C2 | 133 (7) | H8'1—C8'—H8'2 | 109.5 |
C4—C3—C2 | 110.0 (4) | C7'—C8'—H8'3 | 109.5 |
N1—C4—C3 | 103.0 (4) | H8'1—C8'—H8'3 | 109.5 |
N1—C4—H4A | 111.2 | H8'2—C8'—H8'3 | 109.5 |
C3—C4—H4A | 111.2 | ||
C5—N2—O1—C6 | −104.6 (6) | C5—C2—C3—C4 | −137.4 (4) |
C3—N4—O2—C7 | −171.4 (14) | C1—C2—C3—C4 | −13.5 (5) |
C3—N4'—O2'—C7' | 167 (9) | C1—N1—C4—C3 | 30.2 (5) |
C4—N1—C1—C2 | −39.6 (5) | N4—C3—C4—N1 | 171.6 (16) |
N1—C1—C2—C5 | 154.7 (4) | N4'—C3—C4—N1 | −179 (8) |
N1—C1—C2—C3 | 31.5 (5) | C2—C3—C4—N1 | −9.5 (5) |
O2—N4—C3—C4 | 1 (3) | O1—N2—C5—N3 | 2.4 (8) |
O2—N4—C3—C2 | −177.3 (9) | O1—N2—C5—C2 | −177.8 (4) |
O2'—N4'—C3—N4 | −13 (25) | C3—C2—C5—N3 | 60.0 (6) |
O2'—N4'—C3—C4 | −163 (7) | C1—C2—C5—N3 | −56.7 (6) |
O2'—N4'—C3—C2 | 31 (17) | C3—C2—C5—N2 | −119.7 (5) |
C5—C2—C3—N4 | 41.6 (15) | C1—C2—C5—N2 | 123.6 (5) |
C1—C2—C3—N4 | 165.4 (14) | N4—O2—C7—C8 | 176.7 (14) |
C5—C2—C3—N4' | 29 (9) | N4'—O2'—C7'—C8' | 143 (8) |
C1—C2—C3—N4' | 153 (9) |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3B···Cl1 | 0.86 | 2.29 | 3.144 (4) | 173 |
N3—H3A···Cl1i | 0.86 | 2.41 | 3.213 (4) | 156 |
N2—H2···Cl2ii | 0.86 | 2.21 | 3.029 (4) | 160 |
N1—H1B···Cl2 | 0.90 | 2.18 | 3.035 (4) | 159 |
N1—H1A···Cl1iii | 0.90 | 2.20 | 3.076 (4) | 165 |
Symmetry codes: (i) −x+3/2, y+1/2, z; (ii) −x+1/2, y+1/2, z; (iii) −x+1, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C8H18N4O22+·2Cl− |
Mr | 273.16 |
Crystal system, space group | Orthorhombic, Pbcn |
Temperature (K) | 298 |
a, b, c (Å) | 12.7355 (14), 8.8506 (12), 26.334 (2) |
V (Å3) | 2968.3 (6) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.43 |
Crystal size (mm) | 0.23 × 0.20 × 0.19 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.907, 0.922 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14370, 2597, 1986 |
Rint | 0.062 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.077, 0.210, 1.08 |
No. of reflections | 2597 |
No. of parameters | 170 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.44, −0.33 |
Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1999) and SHELXTL (Sheldrick, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3B···Cl1 | 0.86 | 2.29 | 3.144 (4) | 173.2 |
N3—H3A···Cl1i | 0.86 | 2.41 | 3.213 (4) | 156.2 |
N2—H2···Cl2ii | 0.86 | 2.21 | 3.029 (4) | 159.8 |
N1—H1B···Cl2 | 0.90 | 2.18 | 3.035 (4) | 158.7 |
N1—H1A···Cl1iii | 0.90 | 2.20 | 3.076 (4) | 164.7 |
Symmetry codes: (i) −x+3/2, y+1/2, z; (ii) −x+1/2, y+1/2, z; (iii) −x+1, −y, −z+1. |
Acknowledgements
This work was supported by the IMB Research Foundation.
References
Anderson, V. E. & Osheroff, N. (2001). Curr. Pharm. Des. 7, 337–353. Web of Science CrossRef PubMed CAS Google Scholar
Ball, P., Tilloston, G. & Fernald, A. (1998). Expert Opin. Investig. Drugs, 7, 761–783. CrossRef PubMed CAS Google Scholar
Bruker (1998). SMART. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (1999). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Choi, D. R., Shin, J. H. & Yang, J. (2004). Bioorg. Med. Chem. Lett. 14, 1273–1277. Web of Science CrossRef PubMed CAS Google Scholar
Ray, S., Pathak, S. R. & Chaturvedi, D. (2005). Drugs Future, 30, 161–180. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wang, X. Y., Guo, Q. & Wang, Y. C. (2008). Acta Pharmacol. Sin. 43, 819–827. CAS Google Scholar
Wang, J., Liu, M., Cao, J. & Wang, Y. (2008). Acta Cryst. E64, o2294. Web of Science CSD CrossRef IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Since the discovery of norfloxacin, fluoroquinolone antibacterial agents have emerged as one of the dominant classes of chemotherapeutic drugs for the treatment of various bacterial infections (Ball et al., 1998; Ray et al., 2005). The most intensive structural variations have been carried out on the basic group at the C-7 position. In general, 5- and 6-membered nitrogen heterocycles including piperazinyl, pyrrolidinyl and piperidinyl type side chains have been proven to be the optimal substituents, as evidenced by the compounds currently on the market (Anderson & Osheroff, 2001; Choi et al., 2004). Recently, as part of an ongoing program to find potent new fluoroquinolones displaying strong Gram-positive activity, we have focused our attention on introducing new functional groups to the pyrrolidine ring. We report here the crystal structure of the title compound, which is intended for use as a novel substituent at the C-7 position of fluoroquinolones.
There are two oximes in the molecule of the title compound (Fig. 1). The methyloxime has the Z configuration, and the ethyloxime is disordered, with both Z and E configurations at occupancy factors of 0.840 (8) and 0.160 (8), respectively. In the molecule the N3—C5(1.296 (6) Å) bond length is significantly shorter than the normal C—N single bond (1.47 Å), indicating some delocalization over the N3-C5-N2 group. The five-membered pyrrolidine ring adopts an envelope conformation. In the crystal structure, there are a number of N–H···Cl hydrogen bonds. (Table 1)