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Acta Crystallogr Sect E Struct Rep Online. 2010 September 1; 66(Pt 9): o2240.
Published online 2010 August 11. doi:  10.1107/S1600536810030333
PMCID: PMC3008019

Ethyl 2-methyl-5-oxo-4-(3,4,5-trimeth­oxy­phen­yl)-1,4,5,6,7,8-hexa­hydro­quinoline-3-carboxyl­ate

Abstract

In the mol­ecular structure of the title compound, C22H27NO6, the dihydro­pyridine ring adopts a flattened boat conformation while the cyclo­hexenone ring is in an envelope conformation. In the crystal, mol­ecules stack parallel to the crystallographic a axis linked by inter­molecular N—H(...)O and C—H(...)O hydrogen bonds.

Related literature

For general background to the biological activity of quinoline derivatives, see: Baba (1997 [triangle]); Baba et al. (1997 [triangle],1998 [triangle]); Davies et al. (2005 [triangle]); Rose & Draeger et al. (1992 [triangle]); Warrior et al. (2005 [triangle]).

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Object name is e-66-o2240-scheme1.jpg

Experimental

Crystal data

  • C22H27NO6
  • M r = 401.44
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2240-efi1.jpg
  • a = 7.512 (2) Å
  • b = 10.402 (1) Å
  • c = 14.568 (3) Å
  • α = 109.77 (3)°
  • β = 95.42 (1)°
  • γ = 104.41 (2)°
  • V = 1017.4 (4) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.10 mm−1
  • T = 294 K
  • 0.26 × 0.24 × 0.21 mm

Data collection

  • Nonius MACH3 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.976, T max = 0.980
  • 4471 measured reflections
  • 3574 independent reflections
  • 2653 reflections with I > 2σ(I)
  • R int = 0.013
  • 3 standard reflections every 60 min intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.043
  • wR(F 2) = 0.129
  • S = 1.03
  • 3574 reflections
  • 268 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.23 e Å−3
  • Δρmin = −0.18 e Å−3

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 [triangle]); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1996 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2009 [triangle]); software used to prepare material for publication: SHELXL97.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810030333/jh2183sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810030333/jh2183Isup2.hkl

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

Acknowledgments

VV is grateful to the DST-India for funding through the Young Scientist Scheme (Fast Track Proposal).

supplementary crystallographic information

Comment

Some derivatives of quinoline are naturally occurring alkaloids and are very attractive for their various bioactivities. For example, they have calcium modulatory properties (Rose &Draeger, 1992), antibacterial activity (Davies et al., 2005),fungicidal activity (Warrior et al., 2005) and selective inhibitor of human immunodeficiency virus type I (HIV-1) transcription (Baba, 1997; Baba et al.,1997,1998) etc. Due to these significant biological activities, the structure of a quinoline derivative, ethyl 2-methyl-5-oxo -4-(3,4,5-trimethoxyphenyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate is elucidated and reported.

The dihydropyridine ring of the title molecule adopts a flattened boat conformation. The cyclohexenone ring is in an envelope conformation with atom C3 at the flap. The 3,4,5-trimethoxyphenyl ring and the plane of the dihydropyridine ring (N1/C1/C6/C7/C8/C9) are nearly perpendicular to each other, with a dihedral angle of 89.33 (4)°. In the crystal structure, molecules are linked into a sheet (Fig.2) parallel to the a axis by N—H···O and C—H···O intra and intermolecular hydrogen bonds (Table 1). Further, it is observed that these sheets are assembled through centrosymmetrically related pairs of molecules by C2—H2B···O4 inter molecular hydrogen bond and weak interactions, which stabilize the structure.

Experimental

3,4,5-trimethoxy benzaldehyde (10 mmol), 1,3-cyclohexanedione (10 mmol) and ethyl acetoacetate (10 mmol) were mixed along with 20 ml of ethanol. Ammonium acetate (10 mmol) was added to the mixture and refluxed on water bath for about 1 h. The progress of the reaction was monitored by TLC. After confirming that the reaction got completed, the reaction mixture was allowed to cool to room temperature and left aside for a day. Solid crystals started to grow from the mother liquor. It was filtered and washed with diethyl ether to ensure pure crystals [yield: 60%, m.p. 576–578 K].

Refinement

H atoms were placed at calculated positions and allowed to ride on their carrier atoms with N—H = 0.83 Å, C—H = 0.93–0.97 Å, and Uiso = 1.2Ueq(C) for CH2 and CH groups and Uiso = 1.5Ueq(C) for CH3 group.

Figures

Fig. 1.
The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom-numbering scheme.
Fig. 2.
The packing diagram showing the sheets of hydrogen bonds along the a axis

Crystal data

C22H27NO6Z = 2
Mr = 401.44F(000) = 428
Triclinic, P1Dx = 1.310 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.512 (2) ÅCell parameters from 25 reflections
b = 10.402 (1) Åθ = 2–25°
c = 14.568 (3) ŵ = 0.10 mm1
α = 109.77 (3)°T = 294 K
β = 95.42 (1)°Block, colourless
γ = 104.41 (2)°0.26 × 0.24 × 0.21 mm
V = 1017.4 (4) Å3

Data collection

Nonius MACH3 diffractometer2653 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.013
graphiteθmax = 25.0°, θmin = 2.1°
ω–2θ scansh = −1→8
Absorption correction: ψ scan (North et al., 1968)k = −12→12
Tmin = 0.976, Tmax = 0.980l = −17→17
4471 measured reflections3 standard reflections every 60 min
3574 independent reflections intensity decay: none

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.043H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.129w = 1/[σ2(Fo2) + (0.0609P)2 + 0.3979P] where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
3574 reflectionsΔρmax = 0.23 e Å3
268 parametersΔρmin = −0.18 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.013 (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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
C220.4600 (4)0.2952 (4)0.0056 (2)0.0841 (9)
H22A0.49220.3586−0.02930.101*
H22B0.35340.2153−0.03390.101*
H22C0.56420.26130.01780.101*
H1N−0.286 (4)−0.135 (3)0.2897 (18)0.061 (7)*
O40.68460 (19)0.35699 (15)0.22606 (11)0.0519 (4)
O30.36747 (19)0.26111 (15)0.50993 (10)0.0523 (4)
N1−0.1712 (2)−0.09684 (18)0.30488 (13)0.0405 (4)
O10.41288 (19)−0.16053 (16)0.25103 (12)0.0588 (4)
C60.1238 (2)−0.11864 (19)0.27165 (13)0.0323 (4)
C1−0.0644 (2)−0.17812 (19)0.25700 (13)0.0347 (4)
C80.0925 (2)0.09809 (19)0.40306 (13)0.0346 (4)
C9−0.0944 (2)0.0320 (2)0.38398 (14)0.0356 (4)
C150.4536 (2)0.20151 (19)0.27900 (14)0.0371 (4)
H150.54520.19910.32560.044*
O20.0990 (2)0.30115 (19)0.54511 (14)0.0765 (6)
C50.2404 (3)−0.2085 (2)0.23209 (15)0.0407 (5)
C160.5036 (3)0.28065 (19)0.22121 (15)0.0388 (4)
O60.4166 (2)0.36880 (18)0.09651 (13)0.0659 (5)
C190.1316 (3)0.1295 (2)0.19881 (14)0.0393 (4)
H190.00680.07880.19140.047*
C70.2165 (2)0.03861 (18)0.33288 (13)0.0330 (4)
H70.33320.04710.37400.040*
C140.2679 (2)0.12545 (18)0.26814 (13)0.0332 (4)
O50.0588 (2)0.21801 (19)0.06860 (13)0.0656 (5)
C3−0.0564 (3)−0.3963 (2)0.12134 (17)0.0557 (6)
H3A−0.0602−0.35780.06940.067*
H3B−0.1143−0.49910.09100.067*
C180.1810 (3)0.2088 (2)0.14062 (15)0.0430 (5)
C170.3684 (3)0.2858 (2)0.15175 (15)0.0438 (5)
C110.1788 (3)0.2281 (2)0.49145 (15)0.0446 (5)
C2−0.1646 (3)−0.3315 (2)0.19699 (16)0.0448 (5)
H2A−0.2869−0.33980.16310.054*
H2B−0.1832−0.38400.24080.054*
C10−0.2342 (3)0.0813 (2)0.44419 (16)0.0479 (5)
H10A−0.19860.08850.51120.058*
H10B−0.35650.01350.41520.058*
H10C−0.23660.17330.44450.058*
C40.1457 (3)−0.3643 (2)0.16960 (18)0.0539 (6)
H4A0.1496−0.41980.21110.065*
H4B0.2156−0.39520.11790.065*
C20−0.1304 (3)0.1336 (3)0.04654 (18)0.0630 (7)
H20A−0.19930.1503−0.00500.076*
H20B−0.18350.15880.10510.076*
H20C−0.13690.03420.02440.076*
C210.8277 (3)0.3578 (3)0.29756 (19)0.0573 (6)
H21A0.94660.41460.29350.069*
H21B0.83050.26160.28450.069*
H21C0.80250.39780.36300.069*
C130.6642 (3)0.4322 (3)0.5930 (2)0.0768 (8)
H13A0.72870.51560.65120.092*
H13B0.67680.45440.53470.092*
H13C0.71740.35640.59040.092*
C120.4662 (3)0.3867 (3)0.59723 (18)0.0667 (7)
H12A0.45300.36520.65650.080*
H12B0.41240.46350.60070.080*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C220.0715 (18)0.133 (3)0.080 (2)0.0367 (18)0.0272 (15)0.072 (2)
O40.0339 (8)0.0517 (9)0.0690 (10)0.0004 (6)0.0116 (7)0.0298 (8)
O30.0343 (8)0.0524 (9)0.0480 (8)0.0054 (6)0.0031 (6)−0.0016 (7)
N10.0211 (8)0.0445 (9)0.0519 (10)0.0076 (7)0.0058 (7)0.0150 (8)
O10.0272 (8)0.0560 (9)0.0804 (11)0.0141 (7)0.0118 (7)0.0085 (8)
C60.0257 (9)0.0357 (10)0.0354 (9)0.0083 (7)0.0064 (7)0.0137 (8)
C10.0276 (9)0.0381 (10)0.0394 (10)0.0079 (8)0.0057 (8)0.0172 (8)
C80.0294 (9)0.0378 (10)0.0375 (10)0.0117 (8)0.0073 (8)0.0139 (8)
C90.0310 (10)0.0411 (10)0.0407 (10)0.0154 (8)0.0094 (8)0.0189 (8)
C150.0280 (9)0.0374 (10)0.0428 (11)0.0072 (8)0.0046 (8)0.0139 (8)
O20.0504 (10)0.0693 (11)0.0758 (12)0.0162 (8)0.0164 (9)−0.0140 (9)
C50.0321 (10)0.0433 (11)0.0455 (11)0.0111 (8)0.0085 (8)0.0152 (9)
C160.0322 (10)0.0323 (10)0.0487 (11)0.0065 (8)0.0120 (8)0.0128 (8)
O60.0674 (11)0.0684 (11)0.0800 (12)0.0172 (9)0.0201 (9)0.0508 (10)
C190.0279 (9)0.0405 (10)0.0452 (11)0.0065 (8)0.0061 (8)0.0138 (9)
C70.0230 (8)0.0367 (10)0.0379 (10)0.0082 (7)0.0054 (7)0.0129 (8)
C140.0278 (9)0.0311 (9)0.0370 (10)0.0084 (7)0.0077 (7)0.0082 (8)
O50.0493 (10)0.0834 (12)0.0730 (11)0.0173 (8)−0.0018 (8)0.0458 (10)
C30.0474 (13)0.0447 (12)0.0554 (13)0.0020 (10)0.0087 (10)0.0035 (10)
C180.0408 (11)0.0454 (11)0.0438 (11)0.0160 (9)0.0042 (9)0.0167 (9)
C170.0456 (12)0.0406 (11)0.0496 (12)0.0129 (9)0.0128 (9)0.0215 (9)
C110.0380 (11)0.0462 (11)0.0463 (11)0.0114 (9)0.0111 (9)0.0133 (9)
C20.0322 (10)0.0419 (11)0.0521 (12)0.0030 (8)0.0034 (9)0.0145 (9)
C100.0340 (11)0.0593 (13)0.0570 (13)0.0217 (9)0.0163 (9)0.0223 (10)
C40.0470 (12)0.0435 (12)0.0636 (14)0.0163 (10)0.0146 (11)0.0080 (10)
C200.0466 (13)0.0887 (18)0.0515 (13)0.0309 (13)0.0002 (10)0.0186 (13)
C210.0307 (11)0.0586 (14)0.0789 (16)0.0055 (10)0.0112 (11)0.0268 (12)
C130.0482 (14)0.0747 (17)0.0697 (17)0.0042 (12)−0.0008 (12)−0.0059 (14)
C120.0475 (13)0.0650 (15)0.0528 (14)0.0008 (11)0.0051 (11)−0.0078 (12)

Geometric parameters (Å, °)

C22—O61.402 (3)C19—H190.9300
C22—H22A0.9600C7—C141.525 (2)
C22—H22B0.9600C7—H70.9800
C22—H22C0.9600O5—C181.372 (2)
O4—C161.375 (2)O5—C201.413 (3)
O4—C211.421 (3)C3—C21.506 (3)
O3—C111.350 (2)C3—C41.516 (3)
O3—C121.446 (3)C3—H3A0.9700
N1—C11.374 (2)C3—H3B0.9700
N1—C91.379 (3)C18—C171.399 (3)
N1—H1N0.83 (3)C2—H2A0.9700
O1—C51.234 (2)C2—H2B0.9700
C6—C11.358 (2)C10—H10A0.9600
C6—C51.453 (3)C10—H10B0.9600
C6—C71.512 (3)C10—H10C0.9600
C1—C21.486 (3)C4—H4A0.9700
C8—C91.355 (2)C4—H4B0.9700
C8—C111.461 (3)C20—H20A0.9600
C8—C71.528 (2)C20—H20B0.9600
C9—C101.508 (3)C20—H20C0.9600
C15—C161.379 (3)C21—H21A0.9600
C15—C141.386 (2)C21—H21B0.9600
C15—H150.9300C21—H21C0.9600
O2—C111.209 (2)C13—C121.458 (3)
C5—C41.505 (3)C13—H13A0.9600
C16—C171.389 (3)C13—H13B0.9600
O6—C171.376 (2)C13—H13C0.9600
C19—C181.384 (3)C12—H12A0.9700
C19—C141.387 (3)C12—H12B0.9700
O6—C22—H22A109.5O5—C18—C19125.06 (18)
O6—C22—H22B109.5O5—C18—C17114.73 (18)
H22A—C22—H22B109.5C19—C18—C17120.20 (18)
O6—C22—H22C109.5O6—C17—C16120.62 (18)
H22A—C22—H22C109.5O6—C17—C18120.21 (18)
H22B—C22—H22C109.5C16—C17—C18119.13 (18)
C16—O4—C21117.61 (16)O2—C11—O3121.13 (19)
C11—O3—C12116.21 (17)O2—C11—C8126.93 (19)
C1—N1—C9122.70 (16)O3—C11—C8111.93 (16)
C1—N1—H1N116.1 (17)C1—C2—C3111.44 (16)
C9—N1—H1N120.6 (17)C1—C2—H2A109.3
C1—C6—C5119.71 (16)C3—C2—H2A109.3
C1—C6—C7121.31 (16)C1—C2—H2B109.3
C5—C6—C7118.90 (15)C3—C2—H2B109.3
C6—C1—N1119.52 (17)H2A—C2—H2B108.0
C6—C1—C2124.04 (17)C9—C10—H10A109.5
N1—C1—C2116.30 (16)C9—C10—H10B109.5
C9—C8—C11120.34 (17)H10A—C10—H10B109.5
C9—C8—C7120.86 (17)C9—C10—H10C109.5
C11—C8—C7118.80 (16)H10A—C10—H10C109.5
C8—C9—N1119.58 (17)H10B—C10—H10C109.5
C8—C9—C10126.59 (18)C5—C4—C3113.84 (18)
N1—C9—C10113.77 (16)C5—C4—H4A108.8
C16—C15—C14120.44 (18)C3—C4—H4A108.8
C16—C15—H15119.8C5—C4—H4B108.8
C14—C15—H15119.8C3—C4—H4B108.8
O1—C5—C6121.43 (18)H4A—C4—H4B107.7
O1—C5—C4120.26 (18)O5—C20—H20A109.5
C6—C5—C4118.29 (16)O5—C20—H20B109.5
O4—C16—C15124.14 (18)H20A—C20—H20B109.5
O4—C16—C17115.44 (17)O5—C20—H20C109.5
C15—C16—C17120.42 (17)H20A—C20—H20C109.5
C17—O6—C22113.52 (19)H20B—C20—H20C109.5
C18—C19—C14120.14 (17)O4—C21—H21A109.5
C18—C19—H19119.9O4—C21—H21B109.5
C14—C19—H19119.9H21A—C21—H21B109.5
C6—C7—C14112.18 (15)O4—C21—H21C109.5
C6—C7—C8110.40 (14)H21A—C21—H21C109.5
C14—C7—C8111.39 (14)H21B—C21—H21C109.5
C6—C7—H7107.6C12—C13—H13A109.5
C14—C7—H7107.6C12—C13—H13B109.5
C8—C7—H7107.6H13A—C13—H13B109.5
C15—C14—C19119.66 (17)C12—C13—H13C109.5
C15—C14—C7119.36 (16)H13A—C13—H13C109.5
C19—C14—C7120.98 (16)H13B—C13—H13C109.5
C18—O5—C20118.35 (18)O3—C12—C13110.0 (2)
C2—C3—C4110.79 (18)O3—C12—H12A109.7
C2—C3—H3A109.5C13—C12—H12A109.7
C4—C3—H3A109.5O3—C12—H12B109.7
C2—C3—H3B109.5C13—C12—H12B109.7
C4—C3—H3B109.5H12A—C12—H12B108.2
H3A—C3—H3B108.1
C5—C6—C1—N1171.81 (16)C6—C7—C14—C15−120.58 (18)
C7—C6—C1—N1−5.1 (3)C8—C7—C14—C15115.10 (18)
C5—C6—C1—C2−3.6 (3)C6—C7—C14—C1959.5 (2)
C7—C6—C1—C2179.45 (17)C8—C7—C14—C19−64.8 (2)
C9—N1—C1—C6−14.9 (3)C20—O5—C18—C19−4.4 (3)
C9—N1—C1—C2160.86 (18)C20—O5—C18—C17174.56 (19)
C11—C8—C9—N1−174.65 (17)C14—C19—C18—O5178.62 (19)
C7—C8—C9—N15.4 (3)C14—C19—C18—C17−0.3 (3)
C11—C8—C9—C102.4 (3)C22—O6—C17—C1691.5 (3)
C7—C8—C9—C10−177.55 (17)C22—O6—C17—C18−90.4 (3)
C1—N1—C9—C814.7 (3)O4—C16—C17—O6−3.2 (3)
C1—N1—C9—C10−162.71 (17)C15—C16—C17—O6177.59 (18)
C1—C6—C5—O1−173.80 (19)O4—C16—C17—C18178.77 (17)
C7—C6—C5—O13.2 (3)C15—C16—C17—C18−0.5 (3)
C1—C6—C5—C44.2 (3)O5—C18—C17—O63.4 (3)
C7—C6—C5—C4−178.84 (18)C19—C18—C17—O6−177.62 (18)
C21—O4—C16—C15−2.2 (3)O5—C18—C17—C16−178.56 (18)
C21—O4—C16—C17178.60 (18)C19—C18—C17—C160.5 (3)
C14—C15—C16—O4−178.84 (17)C12—O3—C11—O20.6 (3)
C14—C15—C16—C170.3 (3)C12—O3—C11—C8−178.82 (19)
C1—C6—C7—C14−103.04 (19)C9—C8—C11—O2−12.8 (3)
C5—C6—C7—C1480.0 (2)C7—C8—C11—O2167.2 (2)
C1—C6—C7—C821.8 (2)C9—C8—C11—O3166.62 (17)
C5—C6—C7—C8−155.10 (16)C7—C8—C11—O3−13.4 (2)
C9—C8—C7—C6−22.0 (2)C6—C1—C2—C3−24.4 (3)
C11—C8—C7—C6158.08 (16)N1—C1—C2—C3160.04 (18)
C9—C8—C7—C14103.36 (19)C4—C3—C2—C149.9 (3)
C11—C8—C7—C14−76.6 (2)O1—C5—C4—C3−158.6 (2)
C16—C15—C14—C19−0.2 (3)C6—C5—C4—C323.5 (3)
C16—C15—C14—C7179.89 (16)C2—C3—C4—C5−50.4 (3)
C18—C19—C14—C150.1 (3)C11—O3—C12—C13−164.3 (2)
C18—C19—C14—C7−179.92 (17)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7—H7···O30.982.362.720 (2)101
N1—H1N···O1i0.83 (3)2.21 (3)2.995 (2)160 (3)
C2—H2B···O4ii0.972.553.340 (3)138
C10—H10B···O1i0.962.593.429 (3)146

Symmetry codes: (i) x−1, y, z; (ii) x−1, y−1, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: JH2183).

References

  • Baba, M. (1997). Antivir. Res.33, 141–152. [PubMed]
  • Baba, M., Okamoto, M., Kawamura, M., Makino, M., Higashida, T., Takashi, T., Kimura, Y., Ikeuchi, T., Tetsuka, T. & Okamoto, T. (1998). Mol. Pharm.53, 1097–1103. [PubMed]
  • Baba, M., Okamoto, M., Makino, M., Kimura, Y., Ikeuchi, T., Sakaguchi, T. & Okamoto, T. (1997). Antimicrob. Agents Chemother.41, 1250–1255. [PMC free article] [PubMed]
  • Davies, D. T., Markwell, R. E., Pearson, N. D. & Takle, A. K. (2005). US Patent 6911442.
  • Enraf–Nonius (1994). CAD-4 EXPRESS Enraf–Nonius, Delft, The Netherlands.
  • Harms, K. & Wocadlo, S. (1996). XCAD4 University of Marburg, Germany.
  • North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.
  • Rose, U. & Draeger, M. (1992). J. Med. Chem.35, 2238–2243. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]
  • Warrior, P., Heiman, D. F., Fugiel, J. A. & Petracek, P. D. (2005). WO Patent 2005060748.

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