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O(N-trifluoroacetyl) contact of 2.9573 (14) Å, which indicates the distribution of the positive charge in the N=C—O chain of the heterobicycle.Supporting information
 | Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807036227/cv2282sup1.cif |
 | Structure factor file (CIF format) https://doi.org/10.1107/S1600536807036227/cv2282Isup2.hkl |
CCDC reference: 657855
The slurry of 3-methyl-N-(cyanomethyl)pyrid-2-one (3 g, 20.3 mmol) in 10 ml of acetonitrile was chilled to 228 K and then trifluoroacetic anhydride (10 ml, 15.1 g, 71.9 mmol) was added.
Immediately after addition the temperature of reaction mixture has risen to 263 K and then slowly decreased to 253 K. Reaction mixture was allowed to warm to RT. The formation of new precipitate was observed at 283 K. New precipitate was filtered off, washed with ether and dried. Mother liquor and ether washings were combined and, after staying overnight, new portion of product with identical mp was harvested. 7.17 g of 3,N-bis(trifluoroacetyl)-8-methyloxazolo[3,2-a]pyridinium-2-imidate was obtained. Yield 78%. Mp 485–487 K (decomp.).
1H-NMR spectrum: 9.62 (d, 1H, H5, J56 = 6.6 Hz), 8.18 (d, 1H, H7, J67 = 8.0 Hz), 7.74 (m, 1H, H6), 2.61 (s, 3H, 8-CH3).
C-bound H-atoms were placed in calculated positions (C—H 0.95–0.98 Å) and refined as riding, with Uiso(H) = 1.2–1.5Ueq(C).
Earlier (Rybakov et al., 2002, 2006, 2007; Babaev et al., 2004, 2005), we described successful synthesis of new class of mesoionic compounds. Here we the title compound, (I), which belongs to this class.
The structure of the title compound is shown on Fig. 1. The main structural feature of this molecule is the difference in lengths of two C—O bonds in the oxazole ring, C3—O4 and C5—O4 of 1.3930 (12) and 1.3418 (12) Å, respectively. Additionally, the bond N1—C2 is longer than other two C—N bonds in the bicycle. These facts may demonstrate the separation of charges in the mesoionic system into two parts: N1 atom of the pyridine-2-one-like positively charged fragment and a negatively charged C2—C3—N30—C30—O30 unit. This conclusion also confirmed by relatively short interatomic contacts C2···O30i = 3.1842 (15) Å Å, N1···O30i = 3.1464 (14) Å and C5···O30i = 2.9573 (14)Å [symmetry code: (i) x + 1, y, z]. Interestingly, the group C10═O10 seems to make a smaller contribution to the delocalization of the negative charge, since C10═O10 bond length is relatively long [1.2293(10 Å].
For the crystal structures of related mesoionic compounds, see: Rybakov et al. (2002, 2006, 2007); Babaev et al. (2004, 2005).
Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](http://journals.iucr.org/e/issues/2007/08/00/cv2282/cv2282fig1thm.gif)
| Fig. 1. The molecular structure of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms presented as spheres with arbitrary radius. |
![[Figure 2]](http://journals.iucr.org/e/issues/2007/08/00/cv2282/cv2282fig2thm.gif)
| Fig. 2. Reaction scheme. |
| C12H6F6N2O3 | Z = 2 |
| Mr = 340.19 | F(000) = 340 |
| Triclinic, P1 | Dx = 1.850 Mg m−3 |
| Hall symbol: -P 1 | Melting point: 486 K |
| a = 4.7470 (9) Å | Mo Kα radiation, λ = 0.71073 Å |
| b = 10.020 (2) Å | Cell parameters from 1533 reflections |
| c = 13.121 (3) Å | θ = 3.8–29.6° |
| α = 87.07 (2)° | µ = 0.19 mm−1 |
| β = 85.54 (2)° | T = 100 K |
| γ = 79.16 (2)° | Needle, colourless |
| V = 610.7 (2) Å3 | 0.5 × 0.2 × 0.1 mm |
| Stoe IPDS diffractometer | 3033 reflections with I > 2σ(I) |
| Radiation source: Fine-focus sealed tube | Rint = 0.026 |
| Graphite monochromator | θmax = 30.0°, θmin = 1.6° |
| ω scans | h = −6→6 |
| 3647 measured reflections | k = −14→14 |
| 3561 independent reflections | l = 0→18 |
| 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)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.110 | H-atom parameters constrained |
| S = 1.01 | w = 1/[σ2(Fo2) + (0.0886P)2] where P = (Fo2 + 2Fc2)/3 |
| 3561 reflections | (Δ/σ)max = 0.001 |
| 209 parameters | Δρmax = 0.35 e Å−3 |
| 0 restraints | Δρmin = −0.40 e Å−3 |
| C12H6F6N2O3 | γ = 79.16 (2)° |
| Mr = 340.19 | V = 610.7 (2) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 4.7470 (9) Å | Mo Kα radiation |
| b = 10.020 (2) Å | µ = 0.19 mm−1 |
| c = 13.121 (3) Å | T = 100 K |
| α = 87.07 (2)° | 0.5 × 0.2 × 0.1 mm |
| β = 85.54 (2)° |
| Stoe IPDS diffractometer | 3033 reflections with I > 2σ(I) |
| 3647 measured reflections | Rint = 0.026 |
| 3561 independent reflections |
| R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
| wR(F2) = 0.110 | H-atom parameters constrained |
| S = 1.01 | Δρmax = 0.35 e Å−3 |
| 3561 reflections | Δρmin = −0.40 e Å−3 |
| 209 parameters |
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. |
| x | y | z | Uiso*/Ueq | ||
| N1 | 0.63108 (18) | 1.01569 (9) | 0.80548 (7) | 0.01191 (17) | |
| C2 | 0.5589 (2) | 0.88933 (10) | 0.84072 (8) | 0.01249 (18) | |
| C3 | 0.3972 (2) | 0.85223 (10) | 0.76503 (7) | 0.01096 (18) | |
| N30 | 0.29280 (19) | 0.74182 (9) | 0.75789 (7) | 0.01295 (17) | |
| C30 | 0.1122 (2) | 0.73232 (10) | 0.68501 (8) | 0.01211 (18) | |
| O30 | −0.04146 (17) | 0.82058 (8) | 0.63682 (6) | 0.01681 (16) | |
| C31 | 0.1051 (2) | 0.58336 (11) | 0.66086 (8) | 0.01484 (19) | |
| F31 | 0.19537 (18) | 0.49207 (7) | 0.73456 (6) | 0.02482 (17) | |
| F32 | 0.27332 (18) | 0.54922 (8) | 0.57639 (6) | 0.02720 (18) | |
| F33 | −0.15873 (16) | 0.56834 (8) | 0.64277 (7) | 0.02651 (18) | |
| O4 | 0.36896 (16) | 0.95558 (7) | 0.68932 (5) | 0.01205 (15) | |
| C5 | 0.5181 (2) | 1.04911 (10) | 0.71396 (7) | 0.01127 (18) | |
| C6 | 0.5524 (2) | 1.16465 (10) | 0.65525 (8) | 0.01351 (19) | |
| C61 | 0.4264 (3) | 1.19068 (11) | 0.55323 (8) | 0.0187 (2) | |
| H611 | 0.2354 | 1.1660 | 0.5578 | 0.028* | |
| H612 | 0.5515 | 1.1357 | 0.5020 | 0.028* | |
| H613 | 0.4098 | 1.2873 | 0.5332 | 0.028* | |
| C7 | 0.7143 (2) | 1.24746 (10) | 0.69715 (8) | 0.0158 (2) | |
| H7 | 0.7454 | 1.3286 | 0.6610 | 0.019* | |
| C8 | 0.8325 (2) | 1.21334 (11) | 0.79182 (9) | 0.0166 (2) | |
| H8 | 0.9425 | 1.2716 | 0.8188 | 0.020* | |
| C9 | 0.7914 (2) | 1.09688 (11) | 0.84605 (8) | 0.01452 (19) | |
| H9 | 0.8722 | 1.0735 | 0.9100 | 0.017* | |
| C10 | 0.6568 (2) | 0.82430 (10) | 0.93413 (7) | 0.01208 (18) | |
| O10 | 0.77976 (18) | 0.87764 (9) | 0.99513 (6) | 0.01804 (17) | |
| C11 | 0.6097 (2) | 0.67686 (11) | 0.96014 (8) | 0.01464 (19) | |
| F11 | 0.33178 (15) | 0.66985 (7) | 0.97317 (5) | 0.01881 (15) | |
| F12 | 0.73214 (15) | 0.59253 (7) | 0.88708 (5) | 0.01939 (15) | |
| F13 | 0.72892 (16) | 0.63249 (7) | 1.04720 (5) | 0.02211 (16) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| N1 | 0.0122 (4) | 0.0106 (4) | 0.0132 (4) | −0.0028 (3) | −0.0007 (3) | −0.0005 (3) |
| C2 | 0.0142 (4) | 0.0109 (4) | 0.0130 (4) | −0.0042 (3) | −0.0013 (3) | 0.0015 (3) |
| C3 | 0.0124 (4) | 0.0097 (4) | 0.0101 (4) | −0.0008 (3) | −0.0008 (3) | 0.0013 (3) |
| N30 | 0.0146 (4) | 0.0112 (4) | 0.0140 (4) | −0.0040 (3) | −0.0032 (3) | 0.0001 (3) |
| C30 | 0.0118 (4) | 0.0118 (4) | 0.0130 (4) | −0.0034 (3) | 0.0011 (3) | −0.0014 (3) |
| O30 | 0.0179 (4) | 0.0138 (3) | 0.0191 (4) | −0.0021 (3) | −0.0057 (3) | −0.0003 (3) |
| C31 | 0.0150 (4) | 0.0123 (4) | 0.0183 (4) | −0.0045 (3) | −0.0019 (3) | −0.0020 (3) |
| F31 | 0.0372 (4) | 0.0108 (3) | 0.0269 (4) | −0.0040 (3) | −0.0086 (3) | 0.0032 (3) |
| F32 | 0.0349 (4) | 0.0206 (4) | 0.0266 (4) | −0.0092 (3) | 0.0119 (3) | −0.0122 (3) |
| F33 | 0.0187 (3) | 0.0194 (3) | 0.0449 (5) | −0.0090 (3) | −0.0077 (3) | −0.0046 (3) |
| O4 | 0.0146 (3) | 0.0101 (3) | 0.0121 (3) | −0.0035 (2) | −0.0029 (2) | 0.0007 (2) |
| C5 | 0.0125 (4) | 0.0092 (4) | 0.0123 (4) | −0.0026 (3) | 0.0003 (3) | −0.0017 (3) |
| C6 | 0.0152 (4) | 0.0093 (4) | 0.0151 (4) | −0.0005 (3) | −0.0002 (3) | 0.0011 (3) |
| C61 | 0.0281 (5) | 0.0136 (5) | 0.0151 (5) | −0.0055 (4) | −0.0046 (4) | 0.0037 (4) |
| C7 | 0.0176 (4) | 0.0108 (4) | 0.0192 (5) | −0.0045 (3) | 0.0027 (4) | −0.0007 (3) |
| C8 | 0.0172 (4) | 0.0140 (4) | 0.0200 (5) | −0.0065 (3) | −0.0001 (4) | −0.0028 (4) |
| C9 | 0.0146 (4) | 0.0150 (4) | 0.0149 (4) | −0.0045 (3) | −0.0008 (3) | −0.0025 (3) |
| C10 | 0.0116 (4) | 0.0118 (4) | 0.0124 (4) | −0.0014 (3) | −0.0011 (3) | 0.0005 (3) |
| O10 | 0.0203 (4) | 0.0189 (4) | 0.0165 (4) | −0.0056 (3) | −0.0072 (3) | 0.0006 (3) |
| C11 | 0.0165 (4) | 0.0142 (4) | 0.0126 (4) | −0.0017 (3) | −0.0018 (3) | 0.0018 (3) |
| F11 | 0.0165 (3) | 0.0200 (3) | 0.0206 (3) | −0.0065 (2) | −0.0002 (2) | 0.0030 (2) |
| F12 | 0.0236 (3) | 0.0121 (3) | 0.0207 (3) | 0.0007 (2) | 0.0006 (3) | −0.0017 (2) |
| F13 | 0.0278 (4) | 0.0203 (3) | 0.0187 (3) | −0.0051 (3) | −0.0095 (3) | 0.0081 (3) |
| N1—C5 | 1.3539 (13) | C6—C7 | 1.3904 (15) |
| N1—C9 | 1.3654 (13) | C6—C61 | 1.4994 (15) |
| N1—C2 | 1.4188 (13) | C61—H611 | 0.9800 |
| C2—C3 | 1.4060 (14) | C61—H612 | 0.9800 |
| C2—C10 | 1.4269 (13) | C61—H613 | 0.9800 |
| C3—N30 | 1.3048 (13) | C7—C8 | 1.4027 (15) |
| C3—O4 | 1.3930 (12) | C7—H7 | 0.9500 |
| N30—C30 | 1.3512 (13) | C8—C9 | 1.3731 (15) |
| C30—O30 | 1.2190 (13) | C8—H8 | 0.9500 |
| C30—C31 | 1.5486 (15) | C9—H9 | 0.9500 |
| C31—F33 | 1.3300 (12) | C10—O10 | 1.2250 (13) |
| C31—F32 | 1.3346 (13) | C10—C11 | 1.5525 (15) |
| C31—F31 | 1.3350 (13) | C11—F11 | 1.3314 (13) |
| O4—C5 | 1.3418 (12) | C11—F13 | 1.3330 (12) |
| C5—C6 | 1.3858 (14) | C11—F12 | 1.3350 (13) |
| C5···O30i | 2.9573 (14) | C2···O30i | 3.1842 (15) |
| N1···O30i | 3.1464 (14) | ||
| C5—N1—C9 | 120.67 (9) | C7—C6—C61 | 124.81 (9) |
| C5—N1—C2 | 107.92 (8) | C6—C61—H611 | 109.5 |
| C9—N1—C2 | 131.37 (9) | C6—C61—H612 | 109.5 |
| C3—C2—N1 | 105.57 (8) | H611—C61—H612 | 109.5 |
| C3—C2—C10 | 133.05 (9) | C6—C61—H613 | 109.5 |
| N1—C2—C10 | 121.34 (9) | H611—C61—H613 | 109.5 |
| N30—C3—O4 | 122.04 (9) | H612—C61—H613 | 109.5 |
| N30—C3—C2 | 130.07 (9) | C6—C7—C8 | 121.19 (9) |
| O4—C3—C2 | 107.85 (8) | C6—C7—H7 | 119.4 |
| C3—N30—C30 | 120.87 (9) | C8—C7—H7 | 119.4 |
| O30—C30—N30 | 130.63 (10) | C9—C8—C7 | 120.87 (10) |
| O30—C30—C31 | 116.50 (9) | C9—C8—H8 | 119.6 |
| N30—C30—C31 | 112.87 (9) | C7—C8—H8 | 119.6 |
| F33—C31—F32 | 107.08 (9) | N1—C9—C8 | 118.14 (10) |
| F33—C31—F31 | 107.14 (9) | N1—C9—H9 | 120.9 |
| F32—C31—F31 | 107.10 (9) | C8—C9—H9 | 120.9 |
| F33—C31—C30 | 111.25 (9) | O10—C10—C2 | 123.73 (10) |
| F32—C31—C30 | 109.40 (9) | O10—C10—C11 | 117.61 (9) |
| F31—C31—C30 | 114.52 (9) | C2—C10—C11 | 118.66 (9) |
| C5—O4—C3 | 108.08 (8) | F11—C11—F13 | 107.55 (8) |
| O4—C5—N1 | 110.48 (8) | F11—C11—F12 | 108.62 (9) |
| O4—C5—C6 | 125.43 (9) | F13—C11—F12 | 107.90 (9) |
| N1—C5—C6 | 124.09 (9) | F11—C11—C10 | 112.01 (9) |
| C5—C6—C7 | 115.04 (10) | F13—C11—C10 | 109.26 (9) |
| C5—C6—C61 | 120.12 (9) | F12—C11—C10 | 111.35 (8) |
| C5—N1—C2—C3 | −0.33 (11) | C2—N1—C5—O4 | 2.26 (11) |
| C9—N1—C2—C3 | −177.92 (10) | C9—N1—C5—C6 | −0.22 (15) |
| C5—N1—C2—C10 | 177.68 (9) | C2—N1—C5—C6 | −178.13 (9) |
| C9—N1—C2—C10 | 0.08 (16) | O4—C5—C6—C7 | 179.38 (9) |
| N1—C2—C3—N30 | 175.92 (10) | N1—C5—C6—C7 | −0.18 (14) |
| C10—C2—C3—N30 | −1.75 (19) | O4—C5—C6—C61 | −2.32 (15) |
| N1—C2—C3—O4 | −1.62 (10) | N1—C5—C6—C61 | 178.12 (9) |
| C10—C2—C3—O4 | −179.29 (10) | C5—C6—C7—C8 | 0.32 (15) |
| O4—C3—N30—C30 | −10.94 (15) | C61—C6—C7—C8 | −177.89 (10) |
| C2—C3—N30—C30 | 171.82 (10) | C6—C7—C8—C9 | −0.07 (16) |
| C3—N30—C30—O30 | −22.33 (17) | C5—N1—C9—C8 | 0.47 (14) |
| C3—N30—C30—C31 | 157.68 (9) | C2—N1—C9—C8 | 177.81 (10) |
| O30—C30—C31—F33 | −37.38 (13) | C7—C8—C9—N1 | −0.33 (15) |
| N30—C30—C31—F33 | 142.61 (9) | C3—C2—C10—O10 | −174.34 (11) |
| O30—C30—C31—F32 | 80.73 (12) | N1—C2—C10—O10 | 8.29 (16) |
| N30—C30—C31—F32 | −99.28 (11) | C3—C2—C10—C11 | 6.48 (17) |
| O30—C30—C31—F31 | −159.06 (10) | N1—C2—C10—C11 | −170.89 (9) |
| N30—C30—C31—F31 | 20.94 (12) | O10—C10—C11—F11 | 116.61 (10) |
| N30—C3—O4—C5 | −174.77 (9) | C2—C10—C11—F11 | −64.16 (12) |
| C2—C3—O4—C5 | 3.01 (10) | O10—C10—C11—F13 | −2.45 (13) |
| C3—O4—C5—N1 | −3.29 (10) | C2—C10—C11—F13 | 176.78 (9) |
| C3—O4—C5—C6 | 177.10 (9) | O10—C10—C11—F12 | −121.54 (10) |
| C9—N1—C5—O4 | −179.84 (8) | C2—C10—C11—F12 | 57.70 (12) |
| Symmetry code: (i) x+1, y, z. |
Experimental details
| Crystal data | |
| Chemical formula | C12H6F6N2O3 |
| Mr | 340.19 |
| Crystal system, space group | Triclinic, P1 |
| Temperature (K) | 100 |
| a, b, c (Å) | 4.7470 (9), 10.020 (2), 13.121 (3) |
| α, β, γ (°) | 87.07 (2), 85.54 (2), 79.16 (2) |
| V (Å3) | 610.7 (2) |
| Z | 2 |
| Radiation type | Mo Kα |
| µ (mm−1) | 0.19 |
| Crystal size (mm) | 0.5 × 0.2 × 0.1 |
| Data collection | |
| Diffractometer | Stoe IPDS |
| Absorption correction | – |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 3647, 3561, 3033 |
| Rint | 0.026 |
| (sin θ/λ)max (Å−1) | 0.703 |
| Refinement | |
| R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.110, 1.01 |
| No. of reflections | 3561 |
| No. of parameters | 209 |
| H-atom treatment | H-atom parameters constrained |
| Δρmax, Δρmin (e Å−3) | 0.35, −0.40 |
Computer programs: X-AREA (Stoe & Cie, 2002), X-AREA, X-RED32 (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
| C5···O30i | 2.9573 (14) | C2···O30i | 3.1842 (15) |
| N1···O30i | 3.1464 (14) |
| Symmetry code: (i) x+1, y, z. |
Earlier (Rybakov et al., 2002, 2006, 2007; Babaev et al., 2004, 2005), we described successful synthesis of new class of mesoionic compounds. Here we the title compound, (I), which belongs to this class.
The structure of the title compound is shown on Fig. 1. The main structural feature of this molecule is the difference in lengths of two C—O bonds in the oxazole ring, C3—O4 and C5—O4 of 1.3930 (12) and 1.3418 (12) Å, respectively. Additionally, the bond N1—C2 is longer than other two C—N bonds in the bicycle. These facts may demonstrate the separation of charges in the mesoionic system into two parts: N1 atom of the pyridine-2-one-like positively charged fragment and a negatively charged C2—C3—N30—C30—O30 unit. This conclusion also confirmed by relatively short interatomic contacts C2···O30i = 3.1842 (15) Å Å, N1···O30i = 3.1464 (14) Å and C5···O30i = 2.9573 (14)Å [symmetry code: (i) x + 1, y, z]. Interestingly, the group C10═O10 seems to make a smaller contribution to the delocalization of the negative charge, since C10═O10 bond length is relatively long [1.2293(10 Å].