1,3-Di­acetyl-4-imidazolin-2-one

Crockett, R.; Forrester, A.R.; Howie, R.A.

doi:10.1107/S1600536804005756

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 60| Part 4| April 2004| Pages o558-o560

https://doi.org/10.1107/S1600536804005756

1,3-Diacetyl-4-imidazolin-2-one

Rowena Crockett,^a ‡ Alexander R. Forrester ^a and R. Alan Howie ^a ^*

^aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
^*Correspondence e-mail: r.a.howie@abdn.ac.uk

(Received 9 March 2004; accepted 11 March 2004; online 24 March 2004)

The acetyl substituents of the title compound, C₇H₈N₂O₃, are in the syn configuration. The bond lengths and angles are as expected for a molecule of this kind.

Comment

The molecule of the title compound, (I), is shown in Fig. 1, and bond lengths and angles involving the non-H atoms are given in Table 1 and are generally as expected for a molecule of this kind. The torsion angles, however, clearly demonstrate the syn disposition of the acetyl substituents and are indicative of some departure from planarity in the configuration of the molecule. This departure is further demonstrated by the dihedral angles between the planes of the five-membered ring and those of the acetyl groups [3.1 (4) and 5.9 (3)°] and by displacements of the acetyl O and methyl C atoms from the ring plane by as much as −0.110 (8) and 0.187 (8) Å for atoms O1 and C7, respectively. The distribution of the molecules in the unit cell (Fig. 2) can be interpreted in terms of layers (Fig. 3) parallel to (010) and centred on y = $[1\over 4]$ and $[3\over 4]$ . The layer at y = $[3\over 4]$ is related to that shown in Fig. 3 by the operation of an n-glide plane parallel to (100), which changes the tilt of the molecules from one layer to the next. The whole arrangement brings about the C—H⋯O contacts given in Table 2, along with a C—H⋯π contact involving atoms C7 and H7B and the centroid (Cg) of the five-membered ring [this last with symmetry code (x − $[1\over 2]$ , $[{1 \over 2}]$ − y, z)], for which the C—H, H⋯Cg, H_perp (the perpendicular distance of H7B from the plane of the ring) and C7⋯Cg distances are 0.96, 2.81, 2.79 and 3.640 (3) Å, respectively; the angle at the H atom between H⋯Cg and H_perp is 6°, and the C—H⋯Cg angle is 145°. The contacts involving O1 (Fig. 2 and Table 2) are between the layers and the other two, including the C—H⋯π contact noted above, within them.

Figure 1
The molecule of (I

), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.

Figure 2
The cell contents of (I

). Displacement ellipsoids are drawn at the 50% probability level, H atoms other than those involved in intermolecular contacts (dashed lines) have been omitted and selected atoms are labelled. [Symmetry codes: (i) $[3\over 2]$ − x, $[{1 \over 2}]$ + y, $[{1 \over 2}]$ + z; (ii) x − $[1\over 2]$ , $[{1 \over 2}]$ − y, z; (iii) 1 − x, 1 − y, $[{1 \over 2}]$ + z; (iv) x − 1, y, z; (v) 2 − x, 1 − y, $[{1 \over 2}]$ + z.]

Figure 3
A layer of molecules of (I

) parallel to (010) and centred on y = $[1\over 4]$ . Displacement ellipsoids are drawn at the 50% probability level, H atoms other than those involved in intermolecular contacts (dashed lines) have been omitted and selected atoms are labelled. [Symmetry codes: (i) x − $[1\over 2]$ , $[{1 \over 2}]$ − y, z; (ii) x − 1, y, z; (iii) x, y, 1 + z; (iv) x − $[1\over 2]$ , $[{1 \over 2}]$ − y, 1 + z; (v) x − 1, y, 1 + z.]

Experimental

Compound (I) was prepared by heating a suspension of the parent 4-imidazolin-2-one prepared by the method of Haines et al. (1982 ) (0.84 g, 0.01 mol) in acetic anhydride (30 ml) until the solid had dissolved. The excess of acetic anhydride was evaporated to yield (I) (1.53 g, 91%), which was recrystallized from Et₂O as colourless needles [m.p. 379 K, literature m.p. 379 K (Gilbert, 1932 )]. ν_max (KBr, cm⁻¹): 3130, 1732, 1714, 1385, 1255, 1240, 1132, 1038, 727, 715, 635 and 627; ¹H NMR [CDCl₃/(CF₃CO)₂O]: δ 2.59 (6H, s, CH₃), 7.06 (2H, s, CH); m/z 168 (M⁺, 4%): 126 (13), 84 (100), 43 (50).

Crystal data

C₇H₈N₂O₃
M_r = 168.15
Orthorhombic, Pna2₁
a = 8.156 (4) Å
b = 18.251 (5) Å
c = 5.172 (7) Å
V = 769.9 (11) Å³
Z = 4
D_x = 1.451 Mg m⁻³
Mo Kα radiation
Cell parameters from 14 reflections
θ = 7.6–10.3°
μ = 0.12 mm⁻¹
T = 298 (2) K
Block, colourless
0.50 × 0.40 × 0.30 mm

Data collection

Nicolet P3 four-circle diffractometer
θ–2θ scans
Absorption correction: none
990 measured reflections
990 independent reflections
621 reflections with I > 2σ(I)
θ_max = 27.6°
h = 0 → 10
k = 0 → 23
l = 0 → 6
2 standard reflections every 50 reflections intensity decay: none

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.056
wR(F²) = 0.113
S = 1.01
990 reflections
111 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0435P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

O1—C1	1.199 (5)
O2—C2	1.205 (5)
O3—C6	1.203 (5)
N1—C5	1.401 (6)
N1—C2	1.405 (5)
N1—C1	1.430 (5)
N2—C2	1.397 (5)
N2—C4	1.407 (5)
N2—C6	1.426 (4)
C1—C3	1.487 (7)
C4—C5	1.319 (5)
C6—C7	1.485 (7)

C5—N1—C2	110.0 (3)
C5—N1—C1	121.4 (4)
C2—N1—C1	128.5 (4)
C2—N2—C4	110.6 (3)
C2—N2—C6	127.7 (4)
C4—N2—C6	121.6 (3)
O1—C1—N1	118.0 (4)
O1—C1—C3	124.4 (4)
N1—C1—C3	117.6 (4)
O2—C2—N2	128.4 (4)
O2—C2—N1	128.5 (4)
N2—C2—N1	103.1 (4)
C5—C4—N2	107.6 (4)
C4—C5—N1	108.7 (4)
O3—C6—N2	118.0 (4)
O3—C6—C7	124.1 (4)
N2—C6—C7	117.9 (4)

C2—N1—C1—O1	−175.5 (4)
C5—N1—C1—O1	0.9 (6)
C2—N1—C1—C3	5.2 (6)
C5—N1—C1—C3	−178.5 (4)
C2—N2—C6—O3	175.8 (4)
C4—N2—C6—O3	−5.3 (6)
C2—N2—C6—C7	−5.4 (6)
C4—N2—C6—C7	173.5 (4)

Table 2
Parameters (Å, °) for C—H⋯O contacts between molecules of (I)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯O2ⁱ	0.93	2.59	3.522 (6)	174.7
C5—H5⋯O1ⁱⁱ	0.93	2.54	3.463 (5)	169.8
C7—H7A⋯O1ⁱⁱⁱ	0.96	2.56	3.312 (5)	135.0
Symmetry codes: (i) $[{\script{1\over 2}}+x,{\script{1\over 2}}-y,1+z]$ ; (ii) $[2-x,-y,{\script{1\over 2}}+z]$ ; (iii) $[{\script{3\over 2}}-x,{\script{1\over 2}}+y,z-{\script{1\over 2}}]$ .

In the final stages of refinement, H atoms were introduced in calculated positions, with C—H = 0.93 Å (alkene H atoms) and 0.96 Å (methyl H atoms), and treated using a riding model, with U_iso(H) set at 1.2U_eq(C) and 1.5U_eq(C) for alkene and methyl H atoms, respectively. The rotational orientation of the rigid-body methyl groups was also refined. In the absence of any atom of atomic number higher than that of O, the Flack (1983 ) parameter is, for this refinement, meaningless and the absolute polarity is indeterminate.

Data collection: Nicolet P3 Software (Nicolet, 1980 ); cell refinement: Nicolet P3 Software; data reduction: RDNIC (Howie, 1980 ); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 ); molecular graphics: ORTEP3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536804005756/bt6425sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536804005756/bt6425Isup2.hkl

Computing details top

Data collection: Nicolet P3 Software (Nicolet, 1980); cell refinement: Nicolet P3 Software; data reduction: RDNIC (Howie, 1980); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia. 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

1,3-diacetyl-4-imidazolin-2-one top

Crystal data top

C₇H₈N₂O₃	D_x = 1.451 Mg m⁻³
M_r = 168.15	Melting point: 379 (lit. 379) K
Orthorhombic, Pna2₁	Mo Kα radiation, λ = 0.71073 Å
a = 8.156 (4) Å	Cell parameters from 14 reflections
b = 18.251 (5) Å	θ = 7.6–10.3°
c = 5.172 (7) Å	µ = 0.12 mm⁻¹
V = 769.9 (11) Å³	T = 298 K
Z = 4	Block, colourless
F(000) = 352	0.50 × 0.40 × 0.30 mm

Data collection top

Nicolet P3 four circle diffractometer	R_int = 0.000
Radiation source: normal-focus sealed tube	θ_max = 27.6°, θ_min = 2.2°
Graphite monochromator	h = 0→10
θ–2θ scans	k = 0→23
990 measured reflections	l = 0→6
990 independent reflections	2 standard reflections every 50 reflections
621 reflections with I > 2σ(I)	intensity decay: none

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.113	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.0435P)²] where P = (F_o² + 2F_c²)/3
990 reflections	(Δ/σ)_max < 0.001
111 parameters	Δρ_max = 0.18 e Å⁻³
1 restraint	Δρ_min = −0.17 e Å⁻³

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

6.4918 (0.0220) x - 1.6134 (0.1449) y - 3.0973 (0.0135) z = 4.9755 (0.0222)

* 0.0000 (0.0000) C1 * 0.0000 (0.0000) O1 * 0.0000 (0.0000) C3

Rms deviation of fitted atoms = 0.0000

6.3195 (0.0133) x - 0.9068 (0.0342) y - 3.2595 (0.0091) z = 4.8997 (0.0144)

Angle to previous plane (with approximate e.s.d.) = 3.10 (0.41)

* 0.0047 (0.0023) N1 * -0.0050 (0.0022) C2 * 0.0036 (0.0022) N2 * -0.0007 (0.0024) C4 * -0.0026 (0.0025) C5 - 0.1097 (0.0075) O1 - 0.0448 (0.0067) C1 0.0026 (0.0080) C3 - 0.0297 (0.0058) O2 - 0.0402 (0.0066) O3 0.0348 (0.0066) C6 0.1867 (0.0083) C7

Rms deviation of fitted atoms = 0.0036

6.7793 (0.0139) x - 1.4639 (0.1425) y - 2.8453 (0.0121) z = 5.2256 (0.0505)

Angle to previous plane (with approximate e.s.d.) = 5.88 (0.31)

* 0.0000 (0.0000) C6 * 0.0000 (0.0000) O3 * 0.0000 (0.0000) C7

Rms deviation of fitted atoms = 0.0000

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.

H in calculated positions and refined with a riding model.

In the absence of any atom of atomic number higher than that of O the the Flack x parameter is meaningless and the absolute structure therefore indeterminate.

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

	x	y	z	U_iso*/U_eq
O1	0.8759 (4)	0.00337 (15)	0.2277 (7)	0.0721 (12)
O2	0.7257 (3)	0.19844 (14)	−0.1424 (7)	0.0548 (8)
O3	0.9703 (4)	0.35970 (14)	0.2903 (6)	0.0582 (9)
N1	0.8722 (4)	0.12506 (16)	0.1516 (8)	0.0443 (9)
N2	0.9021 (4)	0.24430 (15)	0.1767 (7)	0.0378 (8)
C1	0.8238 (5)	0.0516 (2)	0.0934 (10)	0.0545 (14)
C2	0.8199 (5)	0.1905 (2)	0.0349 (9)	0.0406 (10)
C3	0.7135 (5)	0.0402 (2)	−0.1319 (12)	0.0672 (14)
H3A	0.7773	0.0389	−0.2877	0.101*
H3B	0.6359	0.0797	−0.1412	0.101*
H3C	0.6560	−0.0054	−0.1121	0.101*
C4	0.9979 (4)	0.2123 (2)	0.3726 (9)	0.0416 (9)
H4	1.0627	0.2371	0.4918	0.050*
C5	0.9790 (5)	0.1406 (2)	0.3565 (10)	0.0458 (11)
H5	1.0284	0.1062	0.4636	0.055*
C6	0.8982 (5)	0.3217 (2)	0.1381 (9)	0.0448 (11)
C7	0.8084 (5)	0.3501 (2)	−0.0906 (10)	0.0556 (13)
H7A	0.8094	0.4027	−0.0879	0.083*
H7B	0.6971	0.3329	−0.0861	0.083*
H7C	0.8606	0.3330	−0.2457	0.083*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.104 (3)	0.0356 (14)	0.077 (3)	−0.0005 (18)	0.000 (2)	0.0069 (18)
O2	0.0523 (16)	0.0546 (17)	0.057 (2)	−0.0017 (14)	−0.006 (2)	0.0000 (19)
O3	0.083 (2)	0.0376 (15)	0.054 (2)	−0.0015 (15)	0.0041 (19)	−0.0037 (16)
N1	0.0455 (19)	0.0373 (16)	0.050 (2)	0.0015 (15)	0.004 (2)	−0.001 (2)
N2	0.0411 (17)	0.0313 (15)	0.0410 (19)	0.0021 (14)	0.0011 (19)	−0.0001 (18)
C1	0.055 (3)	0.040 (2)	0.068 (4)	−0.007 (2)	0.016 (3)	−0.009 (3)
C2	0.039 (2)	0.039 (2)	0.044 (2)	0.0006 (19)	0.009 (2)	0.000 (2)
C3	0.067 (3)	0.050 (2)	0.084 (4)	−0.007 (2)	0.005 (4)	−0.015 (3)
C4	0.042 (2)	0.0430 (19)	0.039 (2)	0.0012 (18)	0.000 (2)	0.006 (2)
C5	0.053 (2)	0.037 (2)	0.047 (3)	0.0097 (18)	0.008 (3)	0.008 (2)
C6	0.051 (3)	0.034 (2)	0.049 (3)	0.003 (2)	0.014 (3)	0.003 (2)
C7	0.064 (3)	0.042 (2)	0.060 (3)	0.007 (2)	0.001 (3)	0.011 (2)

Geometric parameters (Å, º) top

O1—C1	1.199 (5)	C3—H3A	0.9600
O2—C2	1.205 (5)	C3—H3B	0.9600
O3—C6	1.203 (5)	C3—H3C	0.9600
N1—C5	1.401 (6)	C4—C5	1.319 (5)
N1—C2	1.405 (5)	C4—H4	0.9300
N1—C1	1.430 (5)	C5—H5	0.9300
N2—C2	1.397 (5)	C6—C7	1.485 (7)
N2—C4	1.407 (5)	C7—H7A	0.9600
N2—C6	1.426 (4)	C7—H7B	0.9600
C1—C3	1.487 (7)	C7—H7C	0.9600

C5—N1—C2	110.0 (3)	H3B—C3—H3C	109.5
C5—N1—C1	121.4 (4)	C5—C4—N2	107.6 (4)
C2—N1—C1	128.5 (4)	C5—C4—H4	126.2
C2—N2—C4	110.6 (3)	N2—C4—H4	126.2
C2—N2—C6	127.7 (4)	C4—C5—N1	108.7 (4)
C4—N2—C6	121.6 (3)	C4—C5—H5	125.6
O1—C1—N1	118.0 (4)	N1—C5—H5	125.6
O1—C1—C3	124.4 (4)	O3—C6—N2	118.0 (4)
N1—C1—C3	117.6 (4)	O3—C6—C7	124.1 (4)
O2—C2—N2	128.4 (4)	N2—C6—C7	117.9 (4)
O2—C2—N1	128.5 (4)	C6—C7—H7A	109.5
N2—C2—N1	103.1 (4)	C6—C7—H7B	109.5
C1—C3—H3A	109.5	H7A—C7—H7B	109.5
C1—C3—H3B	109.5	C6—C7—H7C	109.5
H3A—C3—H3B	109.5	H7A—C7—H7C	109.5
C1—C3—H3C	109.5	H7B—C7—H7C	109.5
H3A—C3—H3C	109.5

C2—N1—C1—O1	−175.5 (4)	C1—N1—C2—N2	177.6 (4)
C5—N1—C1—O1	0.9 (6)	C2—N2—C4—C5	0.4 (4)
C2—N1—C1—C3	5.2 (6)	C6—N2—C4—C5	−178.7 (3)
C5—N1—C1—C3	−178.5 (4)	N2—C4—C5—N1	0.2 (5)
C4—N2—C2—O2	178.5 (4)	C2—N1—C5—C4	−0.7 (5)
C6—N2—C2—O2	−2.5 (7)	C1—N1—C5—C4	−177.7 (4)
C4—N2—C2—N1	−0.8 (4)	C2—N2—C6—O3	175.8 (4)
C6—N2—C2—N1	178.2 (4)	C4—N2—C6—O3	−5.3 (6)
C5—N1—C2—O2	−178.4 (4)	C2—N2—C6—C7	−5.4 (6)
C1—N1—C2—O2	−1.7 (7)	C4—N2—C6—C7	173.5 (4)
C5—N1—C2—N2	0.9 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O2ⁱ	0.93	2.59	3.522 (6)	175
C5—H5···O1ⁱⁱ	0.93	2.54	3.463 (5)	170
C7—H7A···O1ⁱⁱⁱ	0.96	2.56	3.312 (5)	135

Symmetry codes: (i) x+1/2, −y+1/2, z+1; (ii) −x+2, −y, z+1/2; (iii) −x+3/2, y+1/2, z−1/2.

Footnotes

‡Present address: Swiss Federal Laboratories for Material Testing and Research (EMPA), Überlandstrasse 129, 8600 Dübendorf, Switzerland.

Acknowledgements

Financial support for this work by the SERC is gratefully acknowledged.

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