organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

Ethyl 1-cyclo­propyl-6,7-di­fluoro-8-meth­­oxy-4-oxo-1,4-di­hydro­quinoline-3-carboxyl­ate

aState Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Sciences and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China
*Correspondence e-mail: hxm36547870@163.com

(Received 16 October 2008; accepted 23 October 2008; online 31 October 2008)

In the title compound, C16H15F2NO4, the dihedral angle between the three-membered ring and the quinoline ring system is 64.3 (3)°. In the crystal structure, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules, forming a column running along [101].

Related literature

The title compound is a key inter­mediate in the synthesis of a series of fluoro­quinolones, see: Matsumoto et al. (1996[Matsumoto, T., Hara, M. & Miyashita, K. (1996). PCT Int. Appl. WO 19 951 205.]); Nagano et al. (1989[Nagano, H., Yokota, T. & Katoh, Y. (1989). Eur. Pat. Appl. EP 89 108 963.]); Petersen et al. (1993[Petersen, U., Krebs, A. & Schenke, T. (1993). Eur. Pat. Appl. EP 92 122 058.]).

[Scheme 1]

Experimental

Crystal data
  • C16H15F2NO4

  • Mr = 323.29

  • Monoclinic, C 2/c

  • a = 16.395 (3) Å

  • b = 17.732 (4) Å

  • c = 12.199 (2) Å

  • β = 123.71 (3)°

  • V = 2950.1 (14) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.12 mm−1

  • T = 293 (2) K

  • 0.10 × 0.10 × 0.05 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.988, Tmax = 0.994

  • 2760 measured reflections

  • 2663 independent reflections

  • 1580 reflections with I > 2σ(I)

  • Rint = 0.068

  • 3 standard reflections every 200 reflections intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.061

  • wR(F2) = 0.175

  • S = 1.04

  • 2663 reflections

  • 208 parameters

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.19 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C1—H1A⋯O2i 0.96 2.58 3.220 (8) 124
C12—H12B⋯O2ii 0.97 2.50 3.273 (5) 136
Symmetry codes: (i) [-x, y, -z-{\script{1\over 2}}]; (ii) [-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z].

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]).

Supporting information


Comment top

The title compound, 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylic acid ethyl ester, is a key intermediate to synthesize a series of fluoroquinolones,such as moxifloxacin (Petersen et al., 1993), balofloxacin (Nagano et al., 1989) and gatifloxacin (Matsumoto et al., 1996). As part of our studies in this area, we report here the synthesis and crystal structure of the title compound, (I) (Fig. 1).

The benzene ring and its adjacent six-membered ring were almost coplanar. The dihedral angles between the three-membered ring and the benzene ring is 65.30 (14)°. In the crystal structure, intermolecular C—H···O hydrogen bonds link the molecules, in which they are effective in the stabilization of the structure.

Related literature top

The title compound is a key intermediate in the synthesis of a series of fluoroquinolones, see: Matsumoto et al. (1996); Nagano et al. (1989); Petersen et al. (1993).

Experimental top

A solution of 26 g (0.075 mol) of 3-cyclopropylamino-2- (2,4,5-trifluoro-3-methoxybenzoyl)acrylic acid ethyl ester and 110 ml of DMF was treated with 22 g (0.16 mol) of K2CO3, and then heated to 50 °C with stirring for 1 h. The resulting precipitate was filtered, washed with the mixture of ice and water, and dried to give 23 g of the title compound (yield 95%). Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of a methanol solution.

Refinement top

All H atoms were placed geometrically (C—H = 0.93–0.98 Å) and refined as riding, with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); 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: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
Ethyl 1-cyclopropyl-6,7-difluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate top
Crystal data top
C16H15F2NO4F(000) = 1344
Mr = 323.29Dx = 1.456 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 25 reflections
a = 16.395 (3) Åθ = 9–12°
b = 17.732 (4) ŵ = 0.12 mm1
c = 12.199 (2) ÅT = 293 K
β = 123.71 (3)°Block, colorless
V = 2950.1 (14) Å30.10 × 0.10 × 0.05 mm
Z = 8
Data collection top
Enraf–Nonius CAD-4
diffractometer
1580 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.068
Graphite monochromatorθmax = 25.2°, θmin = 1.9°
ω/2θ scansh = 219
Absorption correction: ψ scan
(North et al., 1968)
k = 021
Tmin = 0.988, Tmax = 0.994l = 1412
2760 measured reflections3 standard reflections every 200 reflections
2663 independent reflections intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.061H-atom parameters constrained
wR(F2) = 0.175 w = 1/[σ2(Fo2) + (0.06P)2 + 5P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
2663 reflectionsΔρmax = 0.21 e Å3
208 parametersΔρmin = 0.19 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008)
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0026 (5)
Crystal data top
C16H15F2NO4V = 2950.1 (14) Å3
Mr = 323.29Z = 8
Monoclinic, C2/cMo Kα radiation
a = 16.395 (3) ŵ = 0.12 mm1
b = 17.732 (4) ÅT = 293 K
c = 12.199 (2) Å0.10 × 0.10 × 0.05 mm
β = 123.71 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
1580 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.068
Tmin = 0.988, Tmax = 0.9943 standard reflections every 200 reflections
2760 measured reflections intensity decay: none
2663 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0610 restraints
wR(F2) = 0.175H-atom parameters constrained
S = 1.04Δρmax = 0.21 e Å3
2663 reflectionsΔρmin = 0.19 e Å3
208 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N0.1306 (2)0.28705 (16)0.2762 (2)0.0512 (7)
O10.1226 (2)0.17328 (16)0.4536 (2)0.0752 (8)
F10.1209 (2)0.01688 (12)0.1874 (3)0.1108 (10)
C10.0365 (4)0.1548 (3)0.5789 (4)0.1079 (18)
H1A0.00940.19570.60880.162*
H1B0.00720.11000.57090.162*
H1C0.05390.14620.64120.162*
O20.1328 (2)0.21459 (14)0.0430 (2)0.0736 (8)
F20.1196 (2)0.02669 (13)0.3966 (3)0.0991 (9)
C20.1223 (2)0.1543 (2)0.3446 (3)0.0550 (9)
O30.1010 (3)0.44539 (16)0.0591 (3)0.0988 (11)
C30.1211 (3)0.0799 (2)0.3166 (4)0.0664 (10)
O40.11605 (19)0.36229 (14)0.0869 (2)0.0666 (7)
C40.1229 (3)0.0575 (2)0.2074 (4)0.0689 (10)
C50.1266 (3)0.1091 (2)0.1231 (4)0.0604 (9)
H5A0.12740.09350.04970.073*
C60.1292 (2)0.18552 (18)0.1466 (3)0.0462 (8)
C70.1284 (2)0.20942 (18)0.2564 (3)0.0447 (8)
C80.1282 (2)0.23918 (19)0.0548 (3)0.0466 (8)
C90.1211 (2)0.31671 (18)0.0906 (3)0.0450 (8)
C100.1234 (2)0.33541 (19)0.1976 (3)0.0520 (8)
H10A0.11960.38640.21760.062*
C110.1438 (3)0.3184 (2)0.3768 (3)0.0650 (11)
H11A0.08540.31830.46720.078*
C120.2375 (3)0.3084 (2)0.3630 (4)0.0737 (11)
H12A0.23620.30110.44280.088*
H12B0.28850.28070.28690.088*
C130.2109 (3)0.3841 (2)0.3402 (4)0.0821 (13)
H13A0.19280.42270.40630.098*
H13B0.24520.40240.25020.098*
C140.1107 (3)0.3813 (2)0.0227 (3)0.0551 (9)
C150.1052 (3)0.4226 (2)0.1578 (4)0.0711 (11)
H15A0.03950.44350.10500.085*
H15B0.15170.46260.17700.085*
C160.1232 (4)0.3914 (3)0.2797 (4)0.0988 (16)
H16A0.11720.43060.32910.148*
H16B0.18820.37060.33080.148*
H16C0.07620.35240.25950.148*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N0.0654 (18)0.0554 (18)0.0445 (15)0.0109 (13)0.0378 (14)0.0036 (13)
O10.097 (2)0.087 (2)0.0541 (15)0.0087 (15)0.0494 (15)0.0196 (13)
F10.182 (3)0.0485 (14)0.160 (3)0.0203 (15)0.131 (2)0.0184 (15)
C10.110 (4)0.158 (5)0.060 (3)0.008 (3)0.049 (3)0.025 (3)
O20.122 (2)0.0632 (16)0.0624 (16)0.0063 (15)0.0677 (17)0.0018 (13)
F20.144 (2)0.0714 (16)0.119 (2)0.0169 (15)0.0963 (19)0.0394 (14)
C20.051 (2)0.070 (3)0.0504 (19)0.0013 (17)0.0323 (16)0.0102 (17)
O30.189 (3)0.0569 (18)0.101 (2)0.0292 (19)0.112 (2)0.0115 (16)
C30.076 (3)0.061 (2)0.075 (2)0.0102 (19)0.050 (2)0.029 (2)
O40.105 (2)0.0581 (15)0.0640 (15)0.0071 (13)0.0637 (15)0.0046 (12)
C40.083 (3)0.048 (2)0.097 (3)0.0039 (19)0.063 (2)0.003 (2)
C50.072 (2)0.054 (2)0.073 (2)0.0034 (18)0.052 (2)0.0022 (19)
C60.0426 (17)0.053 (2)0.0471 (17)0.0039 (15)0.0275 (15)0.0054 (15)
C70.0370 (16)0.055 (2)0.0448 (17)0.0004 (14)0.0242 (14)0.0072 (14)
C80.0433 (17)0.059 (2)0.0429 (17)0.0052 (15)0.0273 (14)0.0085 (15)
C90.0409 (17)0.058 (2)0.0382 (15)0.0037 (14)0.0234 (13)0.0034 (15)
C100.063 (2)0.052 (2)0.0487 (18)0.0101 (16)0.0359 (17)0.0017 (16)
C110.100 (3)0.066 (2)0.0420 (18)0.020 (2)0.047 (2)0.0113 (17)
C120.106 (3)0.072 (3)0.079 (3)0.010 (2)0.074 (3)0.006 (2)
C130.143 (4)0.060 (3)0.084 (3)0.005 (3)0.089 (3)0.009 (2)
C140.072 (2)0.057 (2)0.0516 (19)0.0087 (18)0.0432 (18)0.0020 (17)
C150.107 (3)0.064 (2)0.071 (2)0.012 (2)0.068 (2)0.0086 (19)
C160.145 (4)0.099 (4)0.092 (3)0.014 (3)0.091 (3)0.011 (3)
Geometric parameters (Å, º) top
N—C101.340 (4)C6—C71.398 (4)
N—C71.402 (4)C6—C81.477 (4)
N—C111.468 (4)C8—C91.428 (4)
O1—C21.373 (4)C9—C101.367 (4)
O1—C11.429 (5)C9—C141.479 (4)
F1—C41.345 (4)C10—H10A0.9300
C1—H1A0.9600C11—C121.462 (5)
C1—H1B0.9600C11—C131.491 (6)
C1—H1C0.9600C11—H11A0.9800
O2—C81.233 (4)C12—C131.485 (5)
F2—C31.348 (4)C12—H12A0.9700
C2—C31.365 (5)C12—H12B0.9700
C2—C71.416 (4)C13—H13A0.9700
O3—C141.198 (4)C13—H13B0.9700
C3—C41.374 (5)C15—C161.455 (5)
O4—C141.333 (4)C15—H15A0.9700
O4—C151.448 (4)C15—H15B0.9700
C4—C51.353 (5)C16—H16A0.9600
C5—C61.391 (5)C16—H16B0.9600
C5—H5A0.9300C16—H16C0.9600
C10—N—C7119.0 (3)N—C10—H10A117.0
C10—N—C11117.9 (3)C9—C10—H10A117.0
C7—N—C11123.1 (3)C12—C11—N119.4 (3)
C2—O1—C1116.6 (3)C12—C11—C1360.4 (3)
O1—C1—H1A109.5N—C11—C13118.2 (3)
O1—C1—H1B109.5C12—C11—H11A115.8
H1A—C1—H1B109.5N—C11—H11A115.8
O1—C1—H1C109.5C13—C11—H11A115.8
H1A—C1—H1C109.5C11—C12—C1360.8 (3)
H1B—C1—H1C109.5C11—C12—H12A117.7
C3—C2—O1119.2 (3)C13—C12—H12A117.7
C3—C2—C7118.8 (3)C11—C12—H12B117.7
O1—C2—C7122.0 (3)C13—C12—H12B117.7
F2—C3—C2119.5 (3)H12A—C12—H12B114.8
F2—C3—C4118.7 (4)C12—C13—C1158.8 (3)
C2—C3—C4121.8 (3)C12—C13—H13A117.9
C14—O4—C15116.7 (3)C11—C13—H13A117.9
F1—C4—C5121.3 (4)C12—C13—H13B117.9
F1—C4—C3118.1 (4)C11—C13—H13B117.9
C5—C4—C3120.6 (4)H13A—C13—H13B115.0
C4—C5—C6119.7 (3)O3—C14—O4122.2 (3)
C4—C5—H5A120.1O3—C14—C9124.0 (3)
C6—C5—H5A120.1O4—C14—C9113.7 (3)
C5—C6—C7120.5 (3)O4—C15—C16107.8 (3)
C5—C6—C8117.2 (3)O4—C15—H15A110.1
C7—C6—C8122.2 (3)C16—C15—H15A110.1
C6—C7—N118.4 (3)O4—C15—H15B110.1
C6—C7—C2118.6 (3)C16—C15—H15B110.1
N—C7—C2123.0 (3)H15A—C15—H15B108.5
O2—C8—C9126.0 (3)C15—C16—H16A109.5
O2—C8—C6119.1 (3)C15—C16—H16B109.5
C9—C8—C6115.0 (3)H16A—C16—H16B109.5
C10—C9—C8119.0 (3)C15—C16—H16C109.5
C10—C9—C14114.9 (3)H16A—C16—H16C109.5
C8—C9—C14126.2 (3)H16B—C16—H16C109.5
N—C10—C9126.0 (3)
C1—O1—C2—C366.2 (5)C5—C6—C8—O25.6 (4)
C1—O1—C2—C7117.1 (4)C7—C6—C8—O2177.2 (3)
O1—C2—C3—F20.4 (5)C5—C6—C8—C9174.0 (3)
C7—C2—C3—F2177.2 (3)C7—C6—C8—C93.1 (4)
O1—C2—C3—C4178.6 (3)O2—C8—C9—C10175.5 (3)
C7—C2—C3—C41.8 (6)C6—C8—C9—C104.9 (4)
F2—C3—C4—F11.4 (6)O2—C8—C9—C144.8 (5)
C2—C3—C4—F1179.6 (3)C6—C8—C9—C14174.8 (3)
F2—C3—C4—C5178.6 (3)C7—N—C10—C95.2 (5)
C2—C3—C4—C50.5 (6)C11—N—C10—C9172.8 (3)
F1—C4—C5—C6179.6 (3)C8—C9—C10—N0.9 (5)
C3—C4—C5—C60.4 (6)C14—C9—C10—N178.8 (3)
C4—C5—C6—C70.2 (5)C10—N—C11—C12110.6 (4)
C4—C5—C6—C8177.0 (3)C7—N—C11—C1267.3 (5)
C5—C6—C7—N179.6 (3)C10—N—C11—C1340.6 (5)
C8—C6—C7—N2.6 (4)C7—N—C11—C13137.3 (3)
C5—C6—C7—C21.6 (4)N—C11—C12—C13107.7 (4)
C8—C6—C7—C2175.5 (3)N—C11—C13—C12109.6 (4)
C10—N—C7—C66.7 (4)C15—O4—C14—O32.7 (5)
C11—N—C7—C6171.2 (3)C15—O4—C14—C9179.2 (3)
C10—N—C7—C2171.3 (3)C10—C9—C14—O32.8 (5)
C11—N—C7—C210.8 (5)C8—C9—C14—O3176.9 (4)
C3—C2—C7—C62.3 (5)C10—C9—C14—O4175.2 (3)
O1—C2—C7—C6179.0 (3)C8—C9—C14—O45.1 (5)
C3—C2—C7—N179.7 (3)C14—O4—C15—C16174.3 (3)
O1—C2—C7—N3.0 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O2i0.962.583.220 (8)124
C12—H12B···O2ii0.972.503.273 (5)136
Symmetry codes: (i) x, y, z1/2; (ii) x+1/2, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC16H15F2NO4
Mr323.29
Crystal system, space groupMonoclinic, C2/c
Temperature (K)293
a, b, c (Å)16.395 (3), 17.732 (4), 12.199 (2)
β (°) 123.71 (3)
V3)2950.1 (14)
Z8
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.10 × 0.10 × 0.05
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.988, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections
2760, 2663, 1580
Rint0.068
(sin θ/λ)max1)0.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.061, 0.175, 1.04
No. of reflections2663
No. of parameters208
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.19

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O2i0.962.583.220 (8)124.0
C12—H12B···O2ii0.972.503.273 (5)136.0
Symmetry codes: (i) x, y, z1/2; (ii) x+1/2, y+1/2, z.
 

References

First citationEnraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationMatsumoto, T., Hara, M. & Miyashita, K. (1996). PCT Int. Appl. WO 19 951 205.  Google Scholar
First citationNagano, H., Yokota, T. & Katoh, Y. (1989). Eur. Pat. Appl. EP 89 108 963.  Google Scholar
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