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Acta Crystallogr Sect E Struct Rep Online. 2009 October 1; 65(Pt 10): o2342–o2343.
Published online 2009 September 5. doi:  10.1107/S1600536809035077
PMCID: PMC2970188

Diethyl 2,6-dimethyl-4-p-tolyl-1,4-dihydro­pyridine-3,5-dicarboxyl­ate

Abstract

In the title compound, C20H25NO4, the 1,4-dihydro­pyridine ring adopts a flattened-boat conformation and forms a dihedral angle of 89.77 (8)° with the benzene ring. Inter­molecular N—H(...)O hydrogen bonds result in the formation of extended chains parallel to the b axis.

Related literature

For general background and applications of 1,4-dihydro­pyridine derivatives, see: Böcker & Guengerich (1986 [triangle]); Cooper et al. (1992 [triangle]); Vo et al. (1995 [triangle]); Gaudio et al. (1994 [triangle]); Gordeev et al. (1996 [triangle]); Sunkel et al. (1992 [triangle]). For ring conformations and ring puckering analysis, see: Boeyens (1978 [triangle]); Cremer & Pople (1975 [triangle]). For related 1,4-dihydro­pyridine structures, see: Fossheim et al. (1982 [triangle]); Teng et al. (2008 [triangle]); Bai et al. (2009 [triangle]). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 [triangle]).

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Object name is e-65-o2342-scheme1.jpg

Experimental

Crystal data

  • C20H25NO4
  • M r = 343.41
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2342-efi1.jpg
  • a = 10.0175 (1) Å
  • b = 7.4287 (1) Å
  • c = 25.0974 (3) Å
  • β = 105.528 (1)°
  • V = 1799.50 (4) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 100 K
  • 0.31 × 0.15 × 0.05 mm

Data collection

  • Bruker SMART APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2005 [triangle]) T min = 0.973, T max = 0.996
  • 20077 measured reflections
  • 5309 independent reflections
  • 3542 reflections with I > 2σ(I)
  • R int = 0.046

Refinement

  • R[F 2 > 2σ(F 2)] = 0.057
  • wR(F 2) = 0.147
  • S = 1.02
  • 5309 reflections
  • 231 parameters
  • H-atom parameters constrained
  • Δρmax = 0.33 e Å−3
  • Δρmin = −0.26 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT (Bruker, 2005 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809035077/tk2533sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809035077/tk2533Isup2.hkl

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

Acknowledgments

HKF and WCL thank Universiti Sains Malaysia (USM) for a Research University Golden Goose grant (No. 1001/PFIZIK/811012). WCL thanks USM for a Research Fellowship. VV is grateful to DST–India for funding through the Young Scientist Scheme (Fast Track Proposal).

supplementary crystallographic information

Comment

Hantzsch 1,4-dihydropyridines (1,4-DHPS) are biologically active compounds which include various vasodilator, anti-hypertensive, bronchodilator, heptaprotective, anti-tumor, anti-mutagenic, geroprotective and anti-diabetic agents (Gaudio et al., 1994). Nifedipine, Nitrendipine and Nimodipine etc., have found commercial utility as calcium channel blockers (Böcker & Guengerich, 1986; Gordeev et al., 1996). For the treatment of congestive heart failure, a number of DHP calcium antagonists have been introduced (Sunkel et al., 1992; Vo et al., 1995). Some DHPs have been introduced as neuroprotectants and cognition enhancers. In addition, a number of DHPs with platelet anti-aggregatory activity have also been discovered (Cooper et al., 1992).

In the title compound (I, Fig. 1), the bond lengths and angles have normal values and are comparable to closely related structures (Teng et al., 2008; Bai et al., 2009). The dihedral angle between the benzene ring and the mean plane of 1,4-dihydropyridine ring is 89.77 (8)°, indicating that both the rings are perpendicular to each other. The 1,4-dihydropyridine ring adopts a flattened-boat conformation (Boeyens, 1978; Cremer & Pople, 1975) with ring distortions at the nitrogen (Nl) and the tetrahedral carbon (C7). Both atoms are displaced in the same direction from the ring with distances of 0.115 (1) Å and 0.151 (2) Å, respectively, from the plane defined by C8, C9, C10, and C11, and form the apexes of a boat-type conformation (Fossheim et al., 1982).

The crystal packing (Fig. 2) is consolidated by intermolecular N1—H1···O1 hydrogen bonds, Table 1, linking the molecules into chains parallel to the b-axis.

Experimental

Compound (I) was prepared according to the Hantzsch pyridine synthesis. A mixture of p-tolylaldehyde (10 mmol), ethylacetoacetate (20 mmol) and ammonium acetate (10 mmol) were heated at 353 K for 2 h (monitored by TLC). After completion of the reaction, the mixture was cooled to room temperature and kept for 2 days to obtain the solid product. The solid that formed was washed using diethyl ether. Solid was collected separately and liquid was kept for solidification. The purity of the crude product was checked through TLC and recrystallized using acetone and ether. The compound was characterized by IR and 1H NMR. M.p. 383–385 K. IR (KBr):υ (cm-1), 3358, 2988, 1695, 1652, 1487, 1214;1H NMR (CDCl3): δ 1.23 (t, 6H, J = 8), δ 2.34 (s, 6H), δ 3.72 (s, 3H), δ 4.09 (m, 4H, J = 4), δ 4.94 (s, 1H), δ 5.58 (s, 1H), δ 6.76–7.21 (4H, aromatic).

Refinement

The N-bound H atom was located in a difference Fourier map and constrained to ride with the parent atom with N-H = 0.84 Å, and with Uiso(H)= 1.2 Ueq(N). C-bound H atoms were positioned geometrically [C—H = 0.93–0.98 Å] and refined using a riding model, with Uiso(H) = 1.2Ueq(C) and 1.5Ueq(methyl-C). A rotating group model was used for the methyl groups.

Figures

Fig. 1.
The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom numbering scheme.
Fig. 2.
Partial unit cell contents for (I) highlighting the formation of supramolecular chains mediated by N-H···O hydrogen bonding (shown as dashed lines).

Crystal data

C20H25NO4F(000) = 736
Mr = 343.41Dx = 1.268 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3769 reflections
a = 10.0175 (1) Åθ = 2.9–27.7°
b = 7.4287 (1) ŵ = 0.09 mm1
c = 25.0974 (3) ÅT = 100 K
β = 105.528 (1)°Plate, colourless
V = 1799.50 (4) Å30.31 × 0.15 × 0.05 mm
Z = 4

Data collection

Bruker SMART APEXII CCD area-detector diffractometer5309 independent reflections
Radiation source: fine-focus sealed tube3542 reflections with I > 2σ(I)
graphiteRint = 0.046
[var phi] and ω scansθmax = 30.1°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2005)h = −14→14
Tmin = 0.973, Tmax = 0.996k = −10→10
20077 measured reflectionsl = −35→30

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)] = 0.057Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.147H-atom parameters constrained
S = 1.02w = 1/[σ2(Fo2) + (0.0648P)2 + 0.5567P] where P = (Fo2 + 2Fc2)/3
5309 reflections(Δ/σ)max = 0.001
231 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = −0.26 e Å3

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
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
O10.22376 (12)0.93012 (15)0.99648 (5)0.0209 (3)
O20.11576 (12)0.74263 (15)1.04170 (5)0.0193 (3)
O30.51279 (12)0.43230 (17)0.85637 (5)0.0263 (3)
O40.43953 (12)0.71714 (16)0.86114 (5)0.0226 (3)
N10.28643 (14)0.30918 (19)0.97456 (6)0.0185 (3)
H10.28000.20430.98580.022*
C10.12624 (18)0.8380 (2)0.84689 (7)0.0239 (4)
H1A0.19200.92930.85590.029*
C20.01109 (18)0.8600 (3)0.80172 (7)0.0257 (4)
H2A0.00130.96540.78100.031*
C3−0.08953 (17)0.7263 (3)0.78718 (7)0.0229 (4)
C4−0.07301 (18)0.5727 (2)0.81972 (7)0.0245 (4)
H4A−0.14010.48290.81150.029*
C50.04298 (17)0.5511 (2)0.86473 (7)0.0216 (4)
H5A0.05230.44650.88580.026*
C60.14465 (16)0.6828 (2)0.87865 (6)0.0161 (3)
C70.27351 (16)0.6541 (2)0.92694 (6)0.0155 (3)
H7A0.32790.76550.93210.019*
C80.23295 (15)0.6169 (2)0.98026 (6)0.0147 (3)
C90.23531 (15)0.4472 (2)1.00053 (6)0.0162 (3)
C100.36055 (16)0.3373 (2)0.93593 (7)0.0172 (3)
C110.36349 (15)0.5037 (2)0.91449 (7)0.0164 (3)
C12−0.21263 (19)0.7489 (3)0.73743 (8)0.0305 (4)
H12A−0.25780.63490.72790.046*
H12B−0.18180.79310.70680.046*
H12C−0.27650.83320.74600.046*
C130.19301 (15)0.7769 (2)1.00645 (6)0.0159 (3)
C140.08916 (17)0.8938 (2)1.07421 (7)0.0209 (4)
H14A0.00750.86931.08680.025*
H14B0.07161.00121.05140.025*
C150.2111 (2)0.9245 (3)1.12300 (8)0.0320 (5)
H15A0.19111.02161.14490.048*
H15B0.29070.95451.11040.048*
H15C0.22960.81701.14500.048*
C160.44652 (16)0.5398 (2)0.87521 (7)0.0190 (3)
C170.50195 (18)0.7686 (3)0.81750 (7)0.0264 (4)
H17A0.58820.70340.82200.032*
H17B0.52310.89620.82040.032*
C180.4070 (2)0.7290 (3)0.76142 (8)0.0313 (4)
H18A0.44280.78400.73350.047*
H18B0.31650.77660.75920.047*
H18C0.40080.60120.75570.047*
C190.19215 (18)0.3867 (2)1.05056 (7)0.0200 (3)
H19A0.23430.46301.08140.030*
H19B0.22140.26461.05920.030*
H19C0.09320.39391.04310.030*
C200.43324 (17)0.1719 (2)0.92385 (7)0.0226 (4)
H20A0.41380.15590.88460.034*
H20B0.40110.06880.93990.034*
H20C0.53130.18520.93940.034*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0275 (6)0.0144 (6)0.0225 (6)0.0008 (5)0.0094 (5)0.0009 (5)
O20.0255 (6)0.0153 (6)0.0205 (6)−0.0024 (5)0.0120 (5)−0.0047 (5)
O30.0255 (6)0.0317 (8)0.0250 (7)0.0015 (5)0.0126 (5)−0.0034 (6)
O40.0257 (6)0.0240 (7)0.0217 (6)−0.0031 (5)0.0124 (5)0.0043 (5)
N10.0245 (7)0.0110 (7)0.0214 (7)−0.0001 (5)0.0086 (6)0.0007 (6)
C10.0240 (8)0.0217 (9)0.0259 (9)−0.0020 (7)0.0066 (7)0.0049 (8)
C20.0272 (9)0.0271 (10)0.0233 (9)0.0056 (7)0.0076 (7)0.0110 (8)
C30.0217 (8)0.0322 (10)0.0157 (8)0.0069 (7)0.0063 (6)−0.0008 (7)
C40.0245 (8)0.0242 (10)0.0229 (9)−0.0027 (7)0.0031 (7)−0.0037 (8)
C50.0267 (8)0.0185 (9)0.0184 (8)−0.0019 (7)0.0038 (7)0.0026 (7)
C60.0184 (7)0.0171 (8)0.0146 (7)0.0022 (6)0.0076 (6)−0.0006 (6)
C70.0180 (7)0.0132 (8)0.0159 (7)−0.0017 (6)0.0057 (6)0.0001 (6)
C80.0164 (7)0.0147 (8)0.0127 (7)−0.0010 (6)0.0034 (6)−0.0010 (6)
C90.0167 (7)0.0165 (8)0.0147 (7)−0.0021 (6)0.0033 (6)−0.0011 (6)
C100.0170 (7)0.0171 (8)0.0172 (8)−0.0016 (6)0.0042 (6)−0.0040 (7)
C110.0164 (7)0.0168 (8)0.0163 (8)−0.0005 (6)0.0047 (6)−0.0031 (6)
C120.0288 (9)0.0388 (12)0.0212 (9)0.0094 (8)0.0023 (7)0.0010 (8)
C130.0148 (7)0.0181 (8)0.0134 (7)−0.0008 (6)0.0015 (6)0.0011 (6)
C140.0245 (8)0.0176 (9)0.0239 (9)0.0005 (7)0.0122 (7)−0.0041 (7)
C150.0378 (11)0.0348 (12)0.0213 (9)0.0069 (9)0.0042 (8)−0.0089 (8)
C160.0156 (7)0.0243 (9)0.0158 (8)−0.0028 (6)0.0022 (6)−0.0029 (7)
C170.0266 (9)0.0334 (11)0.0219 (9)−0.0067 (8)0.0114 (7)0.0030 (8)
C180.0316 (10)0.0387 (12)0.0233 (10)−0.0062 (8)0.0071 (8)0.0032 (8)
C190.0271 (8)0.0146 (8)0.0195 (8)−0.0006 (7)0.0086 (7)0.0015 (7)
C200.0218 (8)0.0193 (9)0.0275 (9)0.0026 (7)0.0079 (7)−0.0015 (7)

Geometric parameters (Å, °)

O1—C131.223 (2)C9—C191.502 (2)
O2—C131.3463 (19)C10—C111.351 (2)
O2—C141.454 (2)C10—C201.500 (2)
O3—C161.213 (2)C11—C161.475 (2)
O4—C161.361 (2)C12—H12A0.9600
O4—C171.450 (2)C12—H12B0.9600
N1—C91.385 (2)C12—H12C0.9600
N1—C101.386 (2)C14—C151.498 (2)
N1—H10.8370C14—H14A0.9700
C1—C61.386 (2)C14—H14B0.9700
C1—C21.394 (2)C15—H15A0.9600
C1—H1A0.9300C15—H15B0.9600
C2—C31.392 (3)C15—H15C0.9600
C2—H2A0.9300C17—C181.502 (2)
C3—C41.387 (3)C17—H17A0.9700
C3—C121.511 (2)C17—H17B0.9700
C4—C51.396 (2)C18—H18A0.9600
C4—H4A0.9300C18—H18B0.9600
C5—C61.387 (2)C18—H18C0.9600
C5—H5A0.9300C19—H19A0.9600
C6—C71.531 (2)C19—H19B0.9600
C7—C111.520 (2)C19—H19C0.9600
C7—C81.524 (2)C20—H20A0.9600
C7—H7A0.9800C20—H20B0.9600
C8—C91.357 (2)C20—H20C0.9600
C8—C131.465 (2)
C13—O2—C14116.54 (13)H12A—C12—H12C109.5
C16—O4—C17116.64 (14)H12B—C12—H12C109.5
C9—N1—C10123.54 (14)O1—C13—O2122.08 (15)
C9—N1—H1117.3O1—C13—C8123.33 (15)
C10—N1—H1118.7O2—C13—C8114.57 (14)
C6—C1—C2121.28 (17)O2—C14—C15110.15 (14)
C6—C1—H1A119.4O2—C14—H14A109.6
C2—C1—H1A119.4C15—C14—H14A109.6
C3—C2—C1120.86 (16)O2—C14—H14B109.6
C3—C2—H2A119.6C15—C14—H14B109.6
C1—C2—H2A119.6H14A—C14—H14B108.1
C4—C3—C2117.94 (16)C14—C15—H15A109.5
C4—C3—C12121.34 (17)C14—C15—H15B109.5
C2—C3—C12120.72 (17)H15A—C15—H15B109.5
C3—C4—C5120.87 (16)C14—C15—H15C109.5
C3—C4—H4A119.6H15A—C15—H15C109.5
C5—C4—H4A119.6H15B—C15—H15C109.5
C6—C5—C4121.24 (16)O3—C16—O4122.14 (15)
C6—C5—H5A119.4O3—C16—C11127.33 (16)
C4—C5—H5A119.4O4—C16—C11110.53 (14)
C1—C6—C5117.77 (15)O4—C17—C18111.28 (14)
C1—C6—C7121.68 (15)O4—C17—H17A109.4
C5—C6—C7120.54 (14)C18—C17—H17A109.4
C11—C7—C8111.04 (13)O4—C17—H17B109.4
C11—C7—C6111.12 (13)C18—C17—H17B109.4
C8—C7—C6110.72 (12)H17A—C17—H17B108.0
C11—C7—H7A107.9C17—C18—H18A109.5
C8—C7—H7A107.9C17—C18—H18B109.5
C6—C7—H7A107.9H18A—C18—H18B109.5
C9—C8—C13124.37 (14)C17—C18—H18C109.5
C9—C8—C7121.06 (14)H18A—C18—H18C109.5
C13—C8—C7114.56 (14)H18B—C18—H18C109.5
C8—C9—N1118.86 (15)C9—C19—H19A109.5
C8—C9—C19127.69 (15)C9—C19—H19B109.5
N1—C9—C19113.42 (14)H19A—C19—H19B109.5
C11—C10—N1119.30 (14)C9—C19—H19C109.5
C11—C10—C20127.24 (15)H19A—C19—H19C109.5
N1—C10—C20113.44 (14)H19B—C19—H19C109.5
C10—C11—C16120.59 (15)C10—C20—H20A109.5
C10—C11—C7120.89 (14)C10—C20—H20B109.5
C16—C11—C7118.37 (14)H20A—C20—H20B109.5
C3—C12—H12A109.5C10—C20—H20C109.5
C3—C12—H12B109.5H20A—C20—H20C109.5
H12A—C12—H12B109.5H20B—C20—H20C109.5
C3—C12—H12C109.5
C6—C1—C2—C30.2 (3)C9—N1—C10—C11−12.4 (2)
C1—C2—C3—C41.4 (3)C9—N1—C10—C20166.21 (14)
C1—C2—C3—C12−178.65 (17)N1—C10—C11—C16177.23 (14)
C2—C3—C4—C5−1.7 (3)C20—C10—C11—C16−1.1 (2)
C12—C3—C4—C5178.29 (16)N1—C10—C11—C7−7.3 (2)
C3—C4—C5—C60.6 (3)C20—C10—C11—C7174.40 (15)
C2—C1—C6—C5−1.4 (3)C8—C7—C11—C1022.6 (2)
C2—C1—C6—C7177.57 (15)C6—C7—C11—C10−101.07 (17)
C4—C5—C6—C11.0 (2)C8—C7—C11—C16−161.75 (13)
C4—C5—C6—C7−177.94 (15)C6—C7—C11—C1674.54 (17)
C1—C6—C7—C11−112.17 (17)C14—O2—C13—O1−9.6 (2)
C5—C6—C7—C1166.73 (19)C14—O2—C13—C8172.05 (13)
C1—C6—C7—C8123.94 (17)C9—C8—C13—O1160.80 (15)
C5—C6—C7—C8−57.15 (19)C7—C8—C13—O1−19.1 (2)
C11—C7—C8—C9−21.7 (2)C9—C8—C13—O2−20.9 (2)
C6—C7—C8—C9102.23 (17)C7—C8—C13—O2159.24 (13)
C11—C7—C8—C13158.16 (13)C13—O2—C14—C15−80.96 (18)
C6—C7—C8—C13−77.91 (16)C17—O4—C16—O37.0 (2)
C13—C8—C9—N1−174.47 (14)C17—O4—C16—C11−172.52 (13)
C7—C8—C9—N15.4 (2)C10—C11—C16—O33.5 (3)
C13—C8—C9—C193.4 (3)C7—C11—C16—O3−172.17 (15)
C7—C8—C9—C19−176.74 (15)C10—C11—C16—O4−177.07 (14)
C10—N1—C9—C813.3 (2)C7—C11—C16—O47.31 (19)
C10—N1—C9—C19−164.90 (14)C16—O4—C17—C1880.78 (19)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.842.152.9684 (18)166

Symmetry codes: (i) x, y−1, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: TK2533).

References

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