4,4-Diacetyl­hepta­nedinitrile

The asymmetric unit of the title compound, C₁₁H₁₄N₂O₂, contains one half-mol­ecule as the central C atom of the mol­ecule lies on a twofold rotation axis. In the crystal structure, weak inter­molecular C—H...N hydrogen bonds link the mol­ecules into zigzag chains along c.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.071
• wR factor = 0.152
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   293.000
            Value of melting point given =     0.000
SHFSU01_ALERT_2_C  Test not performed. _refine_ls_shift/su_max and
            _refine_ls_shift/esd_max not present.
            Absolute value of the parameter shift to su ratio given   0.001
PLAT157_ALERT_4_C Non-standard Monoclinic Beta Angle less 90 Deg        84.91 Deg.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H6B    ..  N       ..       2.66 Ang.

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The biological activity of aminothiazoles has been well documented. They have broad applications in the treatment of allergies, hypertension, schizophrenia,inflammation, bacterial infections, and HIV (Kabalka & Mereddy, 2006). Dicarbonyl compounds represent an important class of starting materials materials used to increase the carbon number of organic compounds (Kim et al., 2001). Many dicarbonyl compounds have been synthesized by the Michael addition method using diethyl malonate as starting compound, but only a few Michael addition diadducts were synthesized under normal conditions (Ranu & Banerjee, 2005; Ranu et al., 2006). We are focusing our synthetic and structural studies on new products of Michael addition reactions from dicarbonyl compounds (Wang et al.,2008) and we report here the crystal structure of the title compound (I), Fig. 1.

All bond lengths are within normal ranges (Allen et al., 1987). The asymmetric unit contains one half-molecule, and the central C4 atom lies on a twofold rotation axis at right angles to the ac plane, which generates the other half-molecule. In the crystal structure weak, intermolecular C6—H6B···N hydrogen bonds link the molecules into zig-zag chains along the c axis, Table 1, Fig 2.

Related literature

For details of the biological activity of aminothiazoles, see: Kabalka & Mereddy (2006). For their use in organic synthesis, see: Kim et al. (2001); Ranu & Banerjee (2005); Ranu et al. (2006); Wang et al. (2008). For bond-length data, see: Allen et al. (1987).

S2. Experimental

2,4-Pentanedione (50 mmol) was dissolved in n-hexane (40 ml) and anhydrous potassium carbonate (100 mmol) and tetrabutylammonium bromide (0.5 g) added. Acrylonitrile (100 mmol) was added dropwise to this solution and the mixture refluxed for 6 h. 50 ml ethyl acetate were then added, the organic layer was filtered and the solvent removed under vacuum to yield the crude product (I). This was crystallized from ethyl acetate (15 ml). Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of acetonitrile.

S3. Refinement

All H atoms were positioned geometrically, with C—H = 0.96 and 0.97 Å for methyl and methylene H atoms, and constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C), where x= 1.5 for methyl H and x = 1.2 for methylene H atoms.

Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. A view of the molecular structure of (I) showing the atom-numbering scheme and 30% displacement ellipsoids (arbitrary spheres for the H atoms).
	Fig. 2. The crystal packing of (I), viewed down the a axis. Hydrogen bonds are drawn as dashed lines.

4,4-Diacetylheptanedinitrile

Crystal data

C11H14N2O2	F(000) = 440
Mr = 206.24	Dx = 1.271 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 25 reflections
a = 12.562 (3) Å	θ = 10–13°
b = 7.8700 (16) Å	µ = 0.09 mm^−1
c = 10.941 (2) Å	T = 293 K
β = 84.91 (3)°	Block, colourless
V = 1077.4 (4) Å^3	0.30 × 0.20 × 0.10 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	758 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.024
Graphite monochromator	θmax = 25.3°, θmin = 3.1°
ω/2θ scans	h = −14→15
Absorption correction: ψ scan (North et al., 1968)	k = 0→9
Tmin = 0.961, Tmax = 0.991	l = 0→13
1009 measured reflections	3 standard reflections every 200 reflections
974 independent reflections	intensity decay: 9%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.071	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.152	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0339P)^2 + 4.1549P] where P = (Fo^2 + 2Fc^2)/3
974 reflections	(Δ/σ)max < 0.001
70 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

Experimental. ¹H NMR (DMSO, δ, p.p.m.) 2.15 (s, 6H), 2.23 (t, 4H), 2.31(t, 4H).

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 (Ų)

	x	y	z	Uiso*/Ueq
O	0.65270 (17)	−0.0258 (3)	0.3475 (2)	0.0523 (7)
N	0.3630 (3)	0.4652 (4)	0.5714 (3)	0.0646 (9)
C1	0.6246 (3)	−0.1760 (4)	0.1653 (3)	0.0495 (9)
H1A	0.6530	−0.1210	0.0912	0.074*
H1B	0.5608	−0.2368	0.1503	0.074*
H1C	0.6765	−0.2541	0.1920	0.074*
C2	0.5988 (2)	−0.0454 (4)	0.2629 (3)	0.0369 (7)
C3	0.5000	0.0686 (5)	0.2500	0.0288 (8)
C4	0.3719 (2)	0.3939 (4)	0.4802 (3)	0.0442 (8)
C5	0.3865 (3)	0.3008 (4)	0.3639 (3)	0.0440 (8)
H5A	0.4002	0.3802	0.2966	0.053*
H5B	0.3218	0.2383	0.3511	0.053*
C6	0.4802 (2)	0.1776 (4)	0.3665 (2)	0.0341 (7)
H6A	0.4670	0.1029	0.4367	0.041*
H6B	0.5445	0.2421	0.3777	0.041*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O	0.0447 (12)	0.0599 (15)	0.0551 (13)	0.0160 (11)	−0.0197 (10)	−0.0091 (12)
N	0.072 (2)	0.0551 (19)	0.0633 (19)	0.0016 (17)	0.0109 (15)	−0.0178 (17)
C1	0.0502 (19)	0.0408 (19)	0.057 (2)	0.0116 (15)	−0.0038 (15)	−0.0075 (16)
C2	0.0355 (15)	0.0341 (16)	0.0418 (16)	0.0002 (13)	−0.0073 (12)	0.0048 (13)
C3	0.0305 (18)	0.0244 (19)	0.0319 (19)	0.000	−0.0057 (15)	0.000
C4	0.0466 (17)	0.0325 (16)	0.0519 (19)	0.0021 (14)	0.0048 (14)	−0.0001 (15)
C5	0.0497 (18)	0.0375 (17)	0.0440 (17)	0.0072 (14)	−0.0005 (13)	−0.0057 (14)
C6	0.0423 (15)	0.0281 (15)	0.0324 (14)	0.0013 (12)	−0.0058 (11)	0.0006 (12)

Geometric parameters (Å, º)

O—C2	1.205 (3)	C3—C6	1.538 (3)
N—C4	1.142 (4)	C4—C5	1.466 (4)
C1—C2	1.497 (4)	C5—C6	1.528 (4)
C1—H1A	0.9600	C5—H5A	0.9700
C1—H1B	0.9600	C5—H5B	0.9700
C1—H1C	0.9600	C6—H6A	0.9700
C2—C3	1.547 (3)	C6—H6B	0.9700
C2—C1—H1A	109.5	N—C4—C5	178.3 (4)
C2—C1—H1B	109.5	C4—C5—C6	109.8 (3)
H1A—C1—H1B	109.5	C4—C5—H5A	109.7
C2—C1—H1C	109.5	C6—C5—H5A	109.7
H1A—C1—H1C	109.5	C4—C5—H5B	109.7
H1B—C1—H1C	109.5	C6—C5—H5B	109.7
O—C2—C1	122.3 (3)	H5A—C5—H5B	108.2
O—C2—C3	120.4 (3)	C5—C6—C3	114.0 (2)
C1—C2—C3	117.2 (2)	C5—C6—H6A	108.8
C6—C3—C6^i	112.2 (3)	C3—C6—H6A	108.8
C6—C3—C2^i	109.09 (15)	C5—C6—H6B	108.8
C6—C3—C2	108.63 (15)	C3—C6—H6B	108.8
C2^i—C3—C2	109.2 (3)	H6A—C6—H6B	107.6
O—C2—C3—C6	−7.9 (4)	C1—C2—C3—C2^i	54.4 (2)
C1—C2—C3—C6	173.3 (3)	C4—C5—C6—C3	178.0 (2)
O—C2—C3—C6^i	114.6 (3)	C6^i—C3—C6—C5	57.5 (2)
C1—C2—C3—C6^i	−64.2 (3)	C2^i—C3—C6—C5	−62.9 (3)
O—C2—C3—C2^i	−126.8 (3)	C2—C3—C6—C5	178.1 (2)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6B···N^ii	0.97	2.66	3.533 (5)	150

Symmetry code: (ii) −x+1, −y+1, −z+1.