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Acta Crystallogr Sect E Struct Rep Online. 2010 November 1; 66(Pt 11): o2891–o2892.
Published online 2010 October 23. doi:  10.1107/S160053681004153X
PMCID: PMC3009270

Dimethyl 2,6,8-trimethyl-1,2-dihydroquinoline-2,4-dicarboxylate

Abstract

The title compound, C16H19NO4, the hydrogenated ring adopts a twisted conformation. In the crystal, inter­molecular C—H(...)O hydrogen bonds link the mol­ecules into centrosymmetric R 2 2(10) dimers. These dimers are further connected via inter­molecular N—H(...)O hydrogen bonds, forming infinite double chains along [001].

Related literature

For the preparation of 1,2-dihydro­quinoline, see: Edwards et al. (1998 [triangle]); Yan et al. (2004 [triangle]); Petasis & Butkevich (2009 [triangle]); Johnson et al. (1989 [triangle]); Waldmann et al. (2008 [triangle]); Rueping & Gültekin (2009 [triangle]). For the biological activity of dihydro­quinolines, see: Elmore et al. (2001 [triangle]); Dillard et al. (1973 [triangle]); Muren & Weissmann (1971 [triangle]). For the preparation of quinolines, see: Dauphinee & Forrest (1978 [triangle]); Yan et al. (2004 [triangle]); Tom & Ruel (2001 [triangle]); Tokuyama et al. (2001 [triangle]); Sarma & Prajapati (2008 [triangle]); Martinez et al. (2008 [triangle]); Huang et al. (2009 [triangle]); Katritzky et al. (1996 [triangle]). For the biological activity of quinolines, see: Hamann et al. (1998 [triangle]); He et al. (2003 [triangle]); LaMontagne et al. (1989 [triangle]). For graph-set analysis, see: Bernstein et al. (1995 [triangle]). For ring puckering parameters, see: Cremer & Pople (1975 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o2891-scheme1.jpg

Experimental

Crystal data

  • C16H19NO4
  • M r = 289.33
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2891-efi1.jpg
  • a = 7.7944 (5) Å
  • b = 23.4621 (8) Å
  • c = 8.2551 (5) Å
  • β = 93.729 (5)°
  • V = 1506.44 (14) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 294 K
  • 0.45 × 0.35 × 0.05 mm

Data collection

  • Nicolet P3 diffractometer
  • 3188 measured reflections
  • 2971 independent reflections
  • 1999 reflections with I > 2σ(I)
  • R int = 0.030
  • 3 standard reflections every 50 reflections intensity decay: 2%

Refinement

  • R[F 2 > 2σ(F 2)] = 0.056
  • wR(F 2) = 0.144
  • S = 1.07
  • 2971 reflections
  • 244 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.19 e Å−3
  • Δρmin = −0.21 e Å−3

Data collection: XSCANS (Siemens, 1996 [triangle]); cell refinement: XSCANS; data reduction: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]) and Mercury (Macrae et al., 2006 [triangle]); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681004153X/su2218sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681004153X/su2218Isup2.hkl

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

Acknowledgments

The authors thank Professor Magnus Rueping of RWTH Aachen University, Germany, for helpful discussions.

supplementary crystallographic information

Comment

Dihydroquinolines have been widely studied and found an important structural unit in synthetic organic and medicinal chemistry (Elmore et al., 2001; Dillard et al., 1973; Muren & Weissmann, 1971). Many dihydroquinoline derivatives have been reported in the literature (Edwards et al., 1998; Yan et al., 2004; Petasis & Butkevich, 2009) and some of them have biological effects. For example, 2,2,4-substituted 1,2-dihydroquinolines have been shown antibacterial activities (Johnson et al., 1989). They are also powerful intermediates for the preparation of quinolines (Dauphinee & Forrest, 1978; Yan et al., 2004; Tom & Ruel, 2001; Tokuyama et al., 2001) and 1,2,3,4-tetrahydroquinolines (Katritzky et al., 1996). Many synthetic methods have been developed for the preparation of quinolines (Sarma & Prajapati, 2008; Martinez et al., 2008; Huang et al., 2009) and many quinolines display biological effects (Hamann et al., 1998; He et al., 2003; LaMontagne et al., 1989).

In the title molecule, illustrated in Fig. 1, ring A (C1-C4/C9/N1) is not planar with the puckering parameters (Cremer & Pople, 1975) QT = 0.358 (2) Å, [var phi] = 155.3 (4)° and θ = 67.1 (4)°.

In the crystal of the title compound intermolecular C-H···O hydrogen bonds (Table 1) link the molecules into R22(10) dimers centered about an inversion center (Bernstein et al., 1995). These dimers are further connected via intermolecular N-H···O hydrogen bonds (Table 1) to form infinite double chains propagating along [001] (Fig. 2).

Experimental

The title compound was synthesized by the literature method (Waldmann et al., 2008). 2,4-dimethylaniline (100 mg, 1 eq) was dissolved in chloroform (1.5 ml) in a screw-capped test tube and Bi(OTf)3 (5 mol%, 0.05 eq) was added to the mixture. The mixture was stirred at room temperature for 6 d until the starting material was completely consumed as monitored by TLC. The resultant residue was directly purified by flash chromatography on silica (EtOAc:Cylohexane 2:98) and gave, in 60% yield, a pale yellow solid. This solid was recrystallized over pentane and ethyl acetate (70:30) to give a pale yellow crystalline solid; Rf 0.25 (2:1 Cyclohexanone/EtOAc); mp. 420-421 K (Rueping & Gültekin, 2009).

Refinement

The C14 and C16 methyl H-atoms were positioned geometrically and constrained to ride on their parent atoms: C-H = 0.96 Å with Uiso(H) = 1.5Ueq(C). The remaining H-atoms were located in a difference Fourier map and were refined isotropically.

Figures

Fig. 1.
The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
Fig. 2.
A partial packing diagram, viewed down the a-axis, of the title compound. Hydrogen bonds are shown as dashed cyan lines (see Table 1 for details).

Crystal data

C16H19NO4F(000) = 616
Mr = 289.33Dx = 1.276 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 26 reflections
a = 7.7944 (5) Åθ = 12–14°
b = 23.4621 (8) ŵ = 0.09 mm1
c = 8.2551 (5) ÅT = 294 K
β = 93.729 (5)°Plate, pale yellow
V = 1506.44 (14) Å30.45 × 0.35 × 0.05 mm
Z = 4

Data collection

Nicolet P3 diffractometerRint = 0.030
Radiation source: fine-focus sealed tubeθmax = 26.0°, θmin = 1.7°
graphiteh = 0→9
Wyckoff–Scan scansk = 0→28
3188 measured reflectionsl = −10→10
2971 independent reflections3 standard reflections every 50 reflections
1999 reflections with I > 2σ(I) intensity decay: 2%

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.144H atoms treated by a mixture of independent and constrained refinement
S = 1.07w = 1/[σ2(Fo2) + (0.0504P)2 + 0.6624P] where P = (Fo2 + 2Fc2)/3
2971 reflections(Δ/σ)max < 0.001
244 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = −0.21 e Å3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
O10.7764 (3)0.59692 (11)−0.3063 (2)0.0640 (6)
O20.5173 (2)0.61471 (9)−0.2180 (2)0.0502 (5)
O31.1234 (3)0.60687 (11)0.3726 (3)0.0738 (7)
O41.1641 (2)0.56175 (9)0.1411 (2)0.0539 (6)
N10.7690 (3)0.60501 (9)0.3076 (3)0.0393 (5)
H10.792 (4)0.6030 (12)0.417 (4)0.054 (9)*
C10.7476 (3)0.61554 (11)−0.0238 (3)0.0334 (5)
C20.8247 (3)0.56972 (11)0.0436 (3)0.0352 (6)
H20.849 (3)0.5376 (11)−0.018 (3)0.035 (7)*
C30.8769 (3)0.56643 (10)0.2214 (3)0.0353 (6)
C40.7347 (3)0.65906 (11)0.2432 (3)0.0341 (5)
C50.7101 (3)0.70451 (12)0.3481 (3)0.0415 (6)
H50.733 (3)0.6993 (10)0.464 (3)0.033 (6)*
C60.6669 (3)0.75784 (12)0.2865 (3)0.0447 (7)
C70.6494 (4)0.76513 (12)0.1202 (4)0.0466 (7)
H70.620 (3)0.8011 (12)0.074 (3)0.046 (8)*
C80.6763 (3)0.72106 (11)0.0118 (3)0.0403 (6)
C90.7161 (3)0.66663 (11)0.0741 (3)0.0342 (5)
C100.6878 (3)0.60882 (11)−0.1978 (3)0.0389 (6)
C110.4423 (5)0.60908 (19)−0.3831 (4)0.0605 (9)
H1110.475 (5)0.6429 (16)−0.448 (4)0.084 (12)*
H1120.485 (5)0.5743 (16)−0.428 (4)0.077 (12)*
H1130.322 (6)0.6056 (16)−0.371 (5)0.095 (13)*
C120.8522 (4)0.50594 (13)0.2861 (4)0.0500 (7)
H1210.873 (4)0.5072 (12)0.407 (4)0.057 (9)*
H1230.734 (4)0.4934 (13)0.252 (4)0.064 (9)*
H1220.926 (4)0.4786 (14)0.238 (4)0.070 (10)*
C131.0681 (3)0.58165 (11)0.2556 (3)0.0376 (6)
C141.3481 (4)0.57041 (17)0.1667 (5)0.0720 (10)
H14A1.40290.56040.06980.108*
H14B1.39240.54680.25490.108*
H14C1.37090.60970.19240.108*
C150.6472 (6)0.80746 (16)0.4010 (5)0.0637 (9)
H1510.582 (6)0.7969 (18)0.496 (5)0.108 (15)*
H1520.588 (6)0.840 (2)0.347 (5)0.115 (16)*
H1530.754 (6)0.8168 (18)0.450 (5)0.109 (16)*
C160.6685 (4)0.73525 (12)−0.1667 (3)0.0536 (8)
H16A0.75860.7154−0.21720.080*
H16B0.68280.7756−0.18020.080*
H16C0.55910.7238−0.21630.080*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0579 (13)0.0996 (18)0.0346 (11)0.0201 (12)0.0036 (9)−0.0042 (11)
O20.0363 (10)0.0755 (14)0.0376 (10)−0.0025 (9)−0.0070 (8)0.0008 (9)
O30.0470 (12)0.106 (2)0.0664 (15)−0.0009 (12)−0.0122 (11)−0.0370 (14)
O40.0303 (9)0.0749 (14)0.0564 (12)−0.0054 (9)0.0028 (8)−0.0166 (10)
N10.0414 (12)0.0463 (13)0.0301 (11)0.0068 (10)0.0026 (9)0.0048 (10)
C10.0252 (11)0.0435 (14)0.0316 (12)−0.0012 (10)0.0020 (9)−0.0001 (10)
C20.0292 (12)0.0376 (14)0.0385 (14)−0.0003 (10)−0.0001 (10)−0.0036 (11)
C30.0321 (13)0.0362 (13)0.0372 (13)0.0009 (10)−0.0006 (10)0.0014 (11)
C40.0245 (11)0.0414 (14)0.0365 (12)0.0002 (10)0.0029 (9)0.0015 (11)
C50.0391 (14)0.0533 (17)0.0326 (14)0.0000 (12)0.0064 (11)−0.0036 (12)
C60.0367 (14)0.0442 (16)0.0538 (17)0.0013 (12)0.0085 (12)−0.0081 (13)
C70.0454 (15)0.0377 (15)0.0563 (18)0.0041 (12)0.0013 (13)0.0031 (13)
C80.0360 (13)0.0437 (15)0.0411 (14)0.0009 (11)0.0015 (11)0.0032 (12)
C90.0282 (11)0.0398 (14)0.0344 (13)0.0003 (10)0.0016 (10)−0.0004 (10)
C100.0385 (13)0.0449 (15)0.0330 (13)0.0026 (11)−0.0014 (11)−0.0008 (11)
C110.056 (2)0.078 (3)0.0452 (18)−0.0146 (19)−0.0160 (15)0.0065 (18)
C120.0518 (18)0.0420 (17)0.0555 (19)−0.0044 (14)−0.0012 (15)0.0088 (14)
C130.0371 (13)0.0382 (14)0.0365 (13)0.0019 (11)−0.0047 (10)0.0003 (11)
C140.0314 (15)0.102 (3)0.083 (2)−0.0042 (17)0.0006 (15)−0.008 (2)
C150.068 (2)0.055 (2)0.070 (2)0.0065 (18)0.014 (2)−0.0184 (18)
C160.066 (2)0.0452 (17)0.0492 (17)0.0033 (14)0.0014 (14)0.0094 (13)

Geometric parameters (Å, °)

O1—C101.199 (3)C6—C151.513 (4)
O2—C101.336 (3)C7—H70.95 (3)
O2—C111.454 (3)C8—C71.392 (4)
O3—C131.189 (3)C8—C161.508 (4)
O4—C131.328 (3)C9—C81.404 (3)
O4—C141.450 (3)C11—H1111.00 (4)
N1—C31.453 (3)C11—H1120.96 (4)
N1—C41.394 (3)C11—H1130.95 (4)
N1—H10.91 (3)C12—H1211.01 (3)
C1—C21.335 (3)C12—H1220.97 (3)
C1—C91.475 (3)C12—H1230.99 (3)
C1—C101.490 (3)C14—H14A0.9600
C2—H20.94 (3)C14—H14B0.9600
C3—C21.499 (3)C14—H14C0.9600
C3—C121.533 (4)C15—H1510.99 (4)
C3—C131.541 (3)C15—H1530.93 (5)
C4—C51.395 (4)C15—H1520.98 (5)
C4—C91.405 (3)C16—H16A0.9600
C5—H50.97 (2)C16—H16B0.9600
C6—C51.384 (4)C16—H16C0.9600
C6—C71.381 (4)
C10—O2—C11116.3 (2)O1—C10—C1125.8 (2)
C13—O4—C14116.4 (2)O2—C10—C1110.9 (2)
C3—N1—H1111.9 (19)O2—C11—H111109 (2)
C4—N1—C3118.9 (2)O2—C11—H112108 (2)
C4—N1—H1116.5 (18)O2—C11—H113104 (2)
C2—C1—C9120.9 (2)H111—C11—H112111 (3)
C2—C1—C10114.9 (2)H113—C11—H111114 (3)
C9—C1—C10124.1 (2)H113—C11—H112110 (3)
C1—C2—C3122.4 (2)C3—C12—H121107.6 (17)
C1—C2—H2121.5 (15)C3—C12—H122112.1 (19)
C3—C2—H2116.2 (15)C3—C12—H123108.2 (18)
N1—C3—C2108.6 (2)H121—C12—H122112 (3)
N1—C3—C12108.4 (2)H121—C12—H123112 (2)
N1—C3—C13110.5 (2)H123—C12—H122105 (3)
C2—C3—C12110.9 (2)O3—C13—O4124.2 (2)
C2—C3—C13111.4 (2)O3—C13—C3124.0 (2)
C12—C3—C13107.0 (2)O4—C13—C3111.8 (2)
N1—C4—C5119.3 (2)O4—C14—H14A109.5
N1—C4—C9119.9 (2)O4—C14—H14B109.5
C5—C4—C9120.7 (2)O4—C14—H14C109.5
C4—C5—H5119.5 (15)H14A—C14—H14B109.5
C6—C5—C4120.2 (2)H14A—C14—H14C109.5
C6—C5—H5120.1 (15)H14B—C14—H14C109.5
C5—C6—C15119.9 (3)C6—C15—H151112 (3)
C7—C6—C5118.9 (3)C6—C15—H152112 (3)
C7—C6—C15121.2 (3)C6—C15—H153109 (3)
C6—C7—C8122.5 (3)H151—C15—H152108 (4)
C6—C7—H7121.0 (16)H151—C15—H153102 (4)
C8—C7—H7116.5 (16)H153—C15—H152113 (4)
C7—C8—C9118.6 (2)C8—C16—H16A109.5
C7—C8—C16117.8 (2)C8—C16—H16B109.5
C9—C8—C16123.5 (2)C8—C16—H16C109.5
C4—C9—C1115.5 (2)H16A—C16—H16B109.5
C8—C9—C1125.4 (2)H16A—C16—H16C109.5
C8—C9—C4119.0 (2)H16B—C16—H16C109.5
O1—C10—O2123.2 (2)
C11—O2—C10—O1−3.4 (4)N1—C3—C13—O323.5 (4)
C11—O2—C10—C1180.0 (3)N1—C3—C13—O4−158.4 (2)
C14—O4—C13—O32.1 (4)C2—C3—C13—O3144.2 (3)
C14—O4—C13—C3−176.1 (2)C2—C3—C13—O4−37.6 (3)
C4—N1—C3—C2−43.0 (3)C12—C3—C13—O3−94.4 (3)
C4—N1—C3—C12−163.6 (2)C12—C3—C13—O483.7 (3)
C4—N1—C3—C1379.5 (3)N1—C4—C5—C6−176.6 (2)
C3—N1—C4—C5−148.5 (2)C9—C4—C5—C60.0 (4)
C3—N1—C4—C934.8 (3)N1—C4—C9—C1−4.2 (3)
C9—C1—C2—C32.5 (4)N1—C4—C9—C8178.1 (2)
C10—C1—C2—C3−173.5 (2)C5—C4—C9—C1179.2 (2)
C2—C1—C9—C4−14.1 (3)C5—C4—C9—C81.5 (4)
C2—C1—C9—C8163.4 (2)C7—C6—C5—C4−0.3 (4)
C10—C1—C9—C4161.5 (2)C15—C6—C5—C4−177.6 (3)
C10—C1—C9—C8−21.0 (4)C5—C6—C7—C8−1.0 (4)
C2—C1—C10—O1−58.1 (4)C15—C6—C7—C8176.3 (3)
C2—C1—C10—O2118.4 (2)C9—C8—C7—C62.6 (4)
C9—C1—C10—O1126.0 (3)C16—C8—C7—C6−174.9 (3)
C9—C1—C10—O2−57.5 (3)C1—C9—C8—C7179.8 (2)
N1—C3—C2—C124.7 (3)C1—C9—C8—C16−2.9 (4)
C12—C3—C2—C1143.8 (3)C4—C9—C8—C7−2.7 (4)
C13—C3—C2—C1−97.2 (3)C4—C9—C8—C16174.5 (2)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.91 (3)2.30 (3)3.190 (3)166 (3)
C2—H2···O4ii0.94 (3)2.54 (3)3.444 (3)162 (2)

Symmetry codes: (i) x, y, z+1; (ii) −x+2, −y+1, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2218).

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