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In the title compound, C20H21NO3, the piperidine ring adopts a chair conformation. The N atom of the piperidine ring shows pyramidal character.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680200065X/ci6074sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S160053680200065X/ci6074Isup2.hkl
Contains datablock I

CCDC reference: 182595

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.004 Å
  • R factor = 0.069
  • wR factor = 0.206
  • Data-to-parameter ratio = 13.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_213 Alert C Atom C33 has ADP max/min Ratio ........... 3.40 prolate PLAT_420 Alert C D-H Without Acceptor N(1) - H(1) ?
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

The preferred conformation of the piperidine ring has been explained by chemical and physical methods, and in most of the derivatives it is found to exist in a chair conformation (Ramalingam et al., 1979). Also, investigations based on photoelectron spectroscopy and semi-empirical calculations show a pyrimidal N atom for the piperidine ring (Woydt et al., 1991). With a view to determining the conformational preference of the piperidine ring when it is substituted with bulky groups like the phenyl group and the ethoxycarbonyl group, the structure determination of the title compound, (I), was undertaken.

The piperidine ring of (I) adopts a slightly distorted chair conformation, with puckering amplitude Q = 0.543 (2) Å, θ = 13.9 (2)° and ϕ = 351.7 (10)° (Cremer & Pople, 1975). The puckering is enhanced at N1 and decreased at C4 (Sekar, Parthasarathy & Rajalingam, 1990; Sekar, Parthasarathy & Radhakrishnan, 1990; Sekar et al., 1993; Ianelli & Nardelli, 1992; Kooijman et al., 1997). The sum of bond angles around N1 (327.7°) indicates sp3 hybridization for N1. The two phenyl rings are equatorially attached to the piperidine ring. The phenyl rings at C2 and C6 form dihedral angles of 72.7 (1) and 53.8 (1)°, respectively, with the piperidine ring. The dihedral angle between the two phenyl ring planes is 37.9 (2)°.

Experimental top

The title compound was synthesized by condensation of 9.90 g (0.100 mol) piperidin-4-one and 10.7 ml (0.100 ml) ethyl acetate in the presence of 0.05 g benzaldehyde and the appropriate aliphatic ketone. The reaction mixture was heated for about 16 h. The solvent was evaporated and the crystals were purified by recrystallization from methanol (m.p. 433 K, yield 70%).

Refinement top

Atoms C32 and C33 of the ethoxycarbonyl group were found to be disordered. The occupancies of the disordered positions C32/C32' and C33/C33' were initially refined and later fixed at 55/45. The corresponding O—C and C—C distances in the major and minor conformers were restrained to be equal. The H atom attached to N1 was located from a difference map and isotropically refined. All other H atoms were geometrically positioned and allowed to ride on their parent atoms.

Computing details top

Data collection: CAD-4 Software (Frenz, 1989); cell refinement: MolEN (Fair,1990); data reduction: MolEN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP97 (Zsolnai, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids. For clarity, only the major (55%) conformer of the ethoxycarbonyl group is shown.
Ethyl 4-oxo-2,6-diphenylpiperidine-3-carboxylate top
Crystal data top
C20H21NO3F(000) = 688
Mr = 323.38Dx = 1.208 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 10.124 (2) ÅCell parameters from 25 reflections
b = 7.801 (3) Åθ = 2–25°
c = 22.896 (3) ŵ = 0.08 mm1
β = 100.39 (1)°T = 293 K
V = 1778.6 (8) Å3Needle, colourless
Z = 40.30 × 0.17 × 0.09 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
2629 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.047
Graphite monochromatorθmax = 25.3°, θmin = 1.8°
ω–2θ scansh = 012
Absorption correction: ψ scan
(North et al., 1968)
k = 09
Tmin = 0.972, Tmax = 0.986l = 2727
3430 measured reflections2 standard reflections every 60 reflections
3236 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)] = 0.069H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.206 w = 1/[σ2(Fo2) + (0.1093P)2 + 0.5001P]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max < 0.001
3236 reflectionsΔρmax = 0.44 e Å3
240 parametersΔρmin = 0.41 e Å3
11 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.011 (1)
Crystal data top
C20H21NO3V = 1778.6 (8) Å3
Mr = 323.38Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.124 (2) ŵ = 0.08 mm1
b = 7.801 (3) ÅT = 293 K
c = 22.896 (3) Å0.30 × 0.17 × 0.09 mm
β = 100.39 (1)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
2629 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.047
Tmin = 0.972, Tmax = 0.9862 standard reflections every 60 reflections
3430 measured reflections intensity decay: none
3236 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.06911 restraints
wR(F2) = 0.206H atoms treated by a mixture of independent and constrained refinement
S = 1.10Δρmax = 0.44 e Å3
3236 reflectionsΔρmin = 0.41 e Å3
240 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*/UeqOcc. (<1)
N10.22618 (16)0.8041 (2)0.05357 (7)0.0533 (5)
H10.1648 (19)0.874 (3)0.0662 (10)0.067 (7)*
C20.35533 (19)0.8391 (3)0.09144 (9)0.0545 (5)
H20.38050.95840.08580.065*
C30.46244 (19)0.7192 (3)0.07300 (9)0.0561 (6)
H30.44290.60190.08420.067*
O40.56073 (18)0.7240 (3)0.01393 (9)0.1000 (8)
C40.4587 (2)0.7226 (3)0.00661 (11)0.0653 (6)
C50.3229 (2)0.7190 (3)0.03089 (10)0.0654 (6)
H5A0.28750.60330.03140.078*
H5B0.33000.74920.07130.078*
C60.22469 (19)0.8419 (3)0.00888 (9)0.0534 (5)
H60.25530.96000.01250.064*
C70.0858 (2)0.8217 (3)0.04577 (9)0.0540 (5)
C80.0148 (2)0.7309 (3)0.02593 (11)0.0690 (7)
H80.00140.68240.01180.083*
C90.1395 (3)0.7118 (4)0.06175 (14)0.0823 (8)
H90.20660.65170.04760.099*
C100.1651 (3)0.7796 (4)0.11737 (14)0.0816 (8)
H100.24860.76430.14150.098*
C110.0666 (3)0.8706 (4)0.13741 (13)0.0852 (8)
H110.08350.91890.17520.102*
C120.0573 (2)0.8908 (4)0.10199 (11)0.0715 (7)
H120.12330.95260.11630.086*
C130.3464 (2)0.8118 (3)0.15574 (9)0.0593 (6)
C140.4162 (3)0.9160 (4)0.19945 (11)0.0830 (8)
H140.46711.00600.18880.100*
C150.4119 (4)0.8897 (6)0.25807 (14)0.1067 (12)
H150.46050.96090.28680.128*
C160.3372 (4)0.7603 (7)0.27461 (13)0.1133 (14)
H160.33370.74380.31450.136*
C170.2670 (3)0.6540 (5)0.23251 (14)0.1010 (11)
H170.21600.56490.24380.121*
C180.2719 (3)0.6797 (4)0.17266 (11)0.0762 (7)
H180.22460.60700.14410.091*
O310.64336 (17)0.9081 (3)0.11099 (10)0.0892 (7)
C310.6011 (2)0.7650 (3)0.10495 (11)0.0673 (6)
O320.67255 (18)0.6267 (3)0.12460 (11)0.1024 (8)
C320.7934 (6)0.6683 (10)0.1695 (3)0.104 (2)0.55
H32A0.79210.61050.20690.125*0.55
H32B0.80250.79080.17630.125*0.55
C330.9020 (8)0.5997 (19)0.1393 (6)0.253 (9)0.55
H33A0.98760.64060.15950.379*0.55
H33B0.88700.63790.09880.379*0.55
H33C0.90100.47670.14030.379*0.55
C32'0.8205 (5)0.6432 (12)0.1322 (4)0.096 (2)0.45
H32C0.84650.73320.10730.115*0.45
H32D0.86230.53620.12390.115*0.45
C33'0.8541 (11)0.6893 (18)0.1973 (4)0.158 (5)0.45
H33D0.93690.75210.20490.237*0.45
H33E0.86320.58640.22070.237*0.45
H33F0.78340.75860.20770.237*0.45
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0440 (9)0.0658 (11)0.0518 (10)0.0002 (8)0.0135 (7)0.0015 (8)
C20.0473 (11)0.0584 (12)0.0580 (12)0.0022 (9)0.0100 (9)0.0005 (9)
C30.0444 (11)0.0628 (12)0.0628 (12)0.0005 (9)0.0143 (9)0.0060 (10)
O40.0555 (10)0.166 (2)0.0865 (13)0.0164 (11)0.0340 (9)0.0159 (13)
C40.0513 (12)0.0811 (16)0.0682 (14)0.0077 (10)0.0233 (10)0.0058 (11)
C50.0563 (12)0.0884 (16)0.0548 (12)0.0081 (11)0.0190 (10)0.0010 (11)
C60.0480 (11)0.0597 (12)0.0542 (11)0.0023 (8)0.0136 (8)0.0029 (9)
C70.0489 (11)0.0563 (11)0.0580 (12)0.0013 (9)0.0130 (9)0.0031 (9)
C80.0554 (13)0.0803 (16)0.0724 (14)0.0084 (11)0.0141 (11)0.0037 (12)
C90.0530 (13)0.0913 (19)0.102 (2)0.0125 (13)0.0134 (13)0.0056 (16)
C100.0571 (14)0.0824 (18)0.097 (2)0.0028 (12)0.0094 (13)0.0090 (15)
C110.0822 (18)0.093 (2)0.0725 (16)0.0014 (15)0.0063 (13)0.0071 (14)
C120.0629 (14)0.0831 (16)0.0662 (14)0.0061 (12)0.0058 (11)0.0089 (12)
C130.0523 (11)0.0704 (14)0.0549 (12)0.0072 (10)0.0089 (9)0.0029 (10)
C140.0745 (16)0.100 (2)0.0703 (16)0.0022 (14)0.0024 (12)0.0185 (14)
C150.107 (2)0.144 (3)0.0644 (18)0.020 (2)0.0005 (16)0.0282 (19)
C160.122 (3)0.168 (4)0.0509 (16)0.049 (3)0.0182 (17)0.005 (2)
C170.106 (2)0.128 (3)0.0745 (19)0.014 (2)0.0326 (17)0.0280 (19)
C180.0809 (16)0.0873 (18)0.0622 (14)0.0003 (14)0.0179 (12)0.0067 (12)
O310.0558 (10)0.0805 (13)0.1287 (17)0.0132 (9)0.0096 (10)0.0093 (11)
C310.0496 (12)0.0720 (15)0.0805 (16)0.0031 (11)0.0126 (11)0.0102 (12)
O320.0609 (11)0.0856 (14)0.145 (2)0.0002 (9)0.0239 (11)0.0235 (12)
C320.082 (4)0.119 (5)0.096 (5)0.002 (4)0.028 (4)0.010 (4)
C330.054 (4)0.326 (17)0.360 (18)0.010 (6)0.010 (6)0.234 (15)
C32'0.061 (4)0.106 (6)0.112 (7)0.016 (4)0.004 (4)0.009 (5)
C33'0.101 (7)0.239 (14)0.114 (7)0.045 (8)0.036 (6)0.049 (8)
Geometric parameters (Å, º) top
N1—C61.457 (3)C13—C181.374 (4)
N1—C21.458 (3)C13—C141.381 (3)
N1—H10.91 (2)C14—C151.366 (4)
C2—C131.506 (3)C14—H140.93
C2—C31.547 (3)C15—C161.355 (6)
C2—H20.98C15—H150.93
C3—C311.505 (3)C16—C171.370 (6)
C3—C41.514 (3)C16—H160.93
C3—H30.98C17—C181.395 (4)
O4—C41.209 (3)C17—H170.93
C4—C51.485 (3)C18—H180.93
C5—C61.530 (3)O31—C311.194 (3)
C5—H5A0.97C31—O321.331 (3)
C5—H5B0.97O32—C32'1.482 (5)
C6—C71.512 (3)O32—C321.485 (4)
C6—H60.98C32—C331.500 (5)
C7—C121.378 (3)C32—H32A0.97
C7—C81.383 (3)C32—H32B0.97
C8—C91.383 (4)C33—H33A0.96
C8—H80.93C33—H33B0.96
C9—C101.360 (4)C33—H33C0.96
C9—H90.93C32'—C33'1.512 (5)
C10—C111.370 (4)C32'—H32C0.97
C10—H100.93C32'—H32D0.97
C11—C121.374 (3)C33'—H33D0.96
C11—H110.93C33'—H33E0.96
C12—H120.93C33'—H33F0.96
C6—N1—C2113.26 (15)C18—C13—C14118.2 (2)
C6—N1—H1107.6 (14)C18—C13—C2121.0 (2)
C2—N1—H1106.8C14—C13—C2120.8 (2)
N1—C2—C13110.44 (16)C15—C14—C13121.4 (3)
N1—C2—C3108.77 (17)C15—C14—H14119.3
C13—C2—C3110.46 (17)C13—C14—H14119.3
N1—C2—H2109.0C16—C15—C14120.3 (3)
C13—C2—H2109.0C16—C15—H15119.9
C3—C2—H2109.0C14—C15—H15119.9
C31—C3—C4109.62 (18)C15—C16—C17120.0 (3)
C31—C3—C2111.22 (18)C15—C16—H16120.0
C4—C3—C2111.82 (17)C17—C16—H16120.0
C31—C3—H3108.0C16—C17—C18119.9 (3)
C4—C3—H3108.0C16—C17—H17120.1
C2—C3—H3108.0C18—C17—H17120.1
O4—C4—C5122.8 (2)C13—C18—C17120.2 (3)
O4—C4—C3121.5 (2)C13—C18—H18119.9
C5—C4—C3115.65 (17)C17—C18—H18119.9
C4—C5—C6112.75 (19)O31—C31—O32123.9 (2)
C4—C5—H5A109.0O31—C31—C3124.2 (2)
C6—C5—H5A109.0O32—C31—C3112.0 (2)
C4—C5—H5B109.0C31—O32—C32'116.4 (4)
C6—C5—H5B109.0C31—O32—C32112.7 (4)
H5A—C5—H5B107.8C32'—O32—C3237.9 (3)
N1—C6—C7111.77 (16)O32—C32—C33100.6 (6)
N1—C6—C5107.68 (17)O32—C32—H32A111.7
C7—C6—C5110.13 (17)C33—C32—H32A111.7
N1—C6—H6109.1O32—C32—H32B111.7
C7—C6—H6109.1C33—C32—H32B111.7
C5—C6—H6109.1H32A—C32—H32B109.4
C12—C7—C8117.7 (2)C32—C33—H33A109.5
C12—C7—C6119.87 (19)C32—C33—H33B109.5
C8—C7—C6122.4 (2)H33A—C33—H33B109.5
C9—C8—C7120.5 (2)C32—C33—H33C109.5
C9—C8—H8119.7H33A—C33—H33C109.5
C7—C8—H8119.7H33B—C33—H33C109.5
C10—C9—C8120.9 (3)O32—C32'—C33'100.3 (6)
C10—C9—H9119.6O32—C32'—H32C111.7
C8—C9—H9119.6C33'—C32'—H32C111.7
C9—C10—C11119.2 (2)O32—C32'—H32D111.7
C9—C10—H10120.4C33'—C32'—H32D111.7
C11—C10—H10120.4H32C—C32'—H32D109.5
C10—C11—C12120.3 (3)C32'—C33'—H33D109.5
C10—C11—H11119.9C32'—C33'—H33E109.5
C12—C11—H11119.9H33D—C33'—H33E109.5
C11—C12—C7121.4 (2)C32'—C33'—H33F109.5
C11—C12—H12119.3H33D—C33'—H33F109.5
C7—C12—H12119.3H33E—C33'—H33F109.5
C6—N1—C2—C13175.15 (17)C8—C7—C12—C110.1 (4)
C6—N1—C2—C363.5 (2)C6—C7—C12—C11178.1 (2)
N1—C2—C3—C31172.47 (17)N1—C2—C13—C1838.2 (3)
C13—C2—C3—C3166.2 (2)C3—C2—C13—C1882.2 (3)
N1—C2—C3—C449.5 (2)N1—C2—C13—C14143.7 (2)
C13—C2—C3—C4170.91 (18)C3—C2—C13—C1495.9 (3)
C31—C3—C4—O415.0 (3)C18—C13—C14—C150.0 (4)
C2—C3—C4—O4138.8 (3)C2—C13—C14—C15178.2 (2)
C31—C3—C4—C5166.7 (2)C13—C14—C15—C160.7 (5)
C2—C3—C4—C542.9 (3)C14—C15—C16—C170.8 (6)
O4—C4—C5—C6136.6 (3)C15—C16—C17—C180.3 (5)
C3—C4—C5—C645.1 (3)C14—C13—C18—C170.5 (4)
C2—N1—C6—C7174.10 (17)C2—C13—C18—C17178.7 (2)
C2—N1—C6—C564.8 (2)C16—C17—C18—C130.4 (5)
C4—C5—C6—N153.3 (2)C4—C3—C31—O3179.3 (3)
C4—C5—C6—C7175.37 (18)C2—C3—C31—O3144.9 (3)
N1—C6—C7—C12164.2 (2)C4—C3—C31—O3299.3 (3)
C5—C6—C7—C1276.2 (3)C2—C3—C31—O32136.5 (2)
N1—C6—C7—C817.7 (3)O31—C31—O32—C32'24.7 (6)
C5—C6—C7—C8101.9 (2)C3—C31—O32—C32'153.9 (4)
C12—C7—C8—C90.2 (4)O31—C31—O32—C3217.0 (5)
C6—C7—C8—C9178.3 (2)C3—C31—O32—C32164.4 (4)
C7—C8—C9—C100.9 (4)C31—O32—C32—C33120.6 (8)
C8—C9—C10—C111.3 (5)C32'—O32—C32—C3316.2 (9)
C9—C10—C11—C121.0 (5)C31—O32—C32'—C33'94.7 (7)
C10—C11—C12—C70.3 (4)C32—O32—C32'—C33'1.1 (8)

Experimental details

Crystal data
Chemical formulaC20H21NO3
Mr323.38
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)10.124 (2), 7.801 (3), 22.896 (3)
β (°) 100.39 (1)
V3)1778.6 (8)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.30 × 0.17 × 0.09
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.972, 0.986
No. of measured, independent and
observed [I > 2σ(I)] reflections
3430, 3236, 2629
Rint0.047
(sin θ/λ)max1)0.601
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.069, 0.206, 1.10
No. of reflections3236
No. of parameters240
No. of restraints11
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.44, 0.41

Computer programs: CAD-4 Software (Frenz, 1989), MolEN (Fair,1990), MolEN, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ZORTEP97 (Zsolnai, 1997), SHELXL97.

Selected torsion angles (º) top
C6—N1—C2—C13175.15 (17)C3—C4—C5—C645.1 (3)
C6—N1—C2—C363.5 (2)C2—N1—C6—C564.8 (2)
N1—C2—C3—C449.5 (2)C4—C5—C6—N153.3 (2)
C2—C3—C4—C542.9 (3)C4—C5—C6—C7175.37 (18)
 

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