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The X-ray crystal structure of the title compound, C
12H
16N
2O
2, has been determined and its structure correlated with its anticonvulsant activity in mice and rats. In each of the two molecules of the asymmetric unit, the two rings are linked by an intramolecular C—H
N hydrogen bond.
Supporting information
CCDC reference: 280424
Key indicators
- Single-crystal X-ray study
- T = 294 K
- Mean (C-C) = 0.005 Å
- R factor = 0.059
- wR factor = 0.148
- Data-to-parameter ratio = 11.3
checkCIF/PLATON results
No syntax errors found
Alert level A
PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ............ 58.93 Deg.
| Author Response: see _publ_section_exptl_refinement
see _publ_section_exptl_refinement
|
Alert level B
THETM01_ALERT_3_B The value of sine(theta_max)/wavelength is less than 0.575
Calculated sin(theta_max)/wavelength = 0.5556
PLAT023_ALERT_3_B Resolution (too) Low [sin(th)/Lambda < 0.6]..... 58.93 Deg.
Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.96
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C5A
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C5B
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.08
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.16
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 5
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety C12A
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 24
1 ALERT level A = In general: serious problem
2 ALERT level B = Potentially serious problem
8 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
4 ALERT type 2 Indicator that the structure model may be wrong or deficient
5 ALERT type 3 Indicator that the structure quality may be low
2 ALERT type 4 Improvement, methodology, query or suggestion
Following the procedure used in the synthesis of 5-methyl-3-(5-methylisoxazol-3-yl)cyclohex-2-enone (Hanson et al., 2006), 5,5-dimethylcyclohexane-1,3-dione (27 mmol) and 3-amino-5-methylisoxazole (33 mmol) produced light-yellow crystals of (II) (yield 3.1 g, 51%; m.p. 477–480 K). Spectroscopic analysis: 1H NMR (DMSO-d6, δ, p.p.m.): 1.0 (6H, s, gem CH3), 2.0 (2H, s, C4 CH2), 2.5 (2H, s, C6 CH2), 3.3 (3H, s, isoxazole CH3), 6.0 (1H, s, ═CH), 6.2 (1H, s, isoxazole CH═), 9.4 (1H, br s, NH). 13C NMR (DMSO-d6, δ, p.p.m.): 5.0, 27.3, 42.0, 41.9, 43.4, 45.5, 47.2, 97.1, 102.3, 105.3, 155.3, 197.1; IR (KBr, ν, cm−1): 3340.5 (NH), 3143.7 (5-methylisoxazole stretch), 1678.6 (C═O).
Diffraction data were collected out to d = 0.8. However, data for d < 0.9 were very weak (less than 1σ) and were thus omitted from the refinement. In view of the importance of this compound in comparison and in contrast with that in the previous paper (Hanson et al., 2006), it was felt that it warranted publication in spite of these limitations. All H atoms were initially located in a difference Fourier map. The methyl H atoms were then constrained to an ideal geometry, with C—H distances of 0.98 Å and Uiso(H) = 1.5Ueq(C), but each group was allowed to rotate freely about its C—C bond. The position of the amine H atom was idealized, with an N—H distance of 0.86 Å and Uiso(H) = 1.2Ueq(N). All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C—H distances in the range 0.95–1.00 Å and Uiso(H) = 1.2Ueq(C).
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: SHELXTL (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
5,5-Dimethyl-3-(5-methylisoxazol-3-yl)cyclohex-2-enone
top
Crystal data top
C12H16N2O2 | Z = 4 |
Mr = 220.27 | F(000) = 472 |
Triclinic, P1 | Dx = 1.210 Mg m−3 |
Hall symbol: -P 1 | Cu Kα radiation, λ = 1.54178 Å |
a = 6.2647 (4) Å | Cell parameters from 36 reflections |
b = 12.2138 (10) Å | θ = 4.2–30.6° |
c = 16.459 (2) Å | µ = 0.68 mm−1 |
α = 101.137 (12)° | T = 294 K |
β = 93.566 (9)° | Lath, colourless |
γ = 100.306 (7)° | 0.50 × 0.12 × 0.08 mm |
V = 1209.6 (2) Å3 | |
Data collection top
Bruker P4 diffractometer | Rint = 0.043 |
Radiation source: fine-focus sealed tube | θmax = 58.9°, θmin = 2.8° |
Graphite monochromator | h = −6→1 |
2θ/ω scans | k = −13→13 |
4192 measured reflections | l = −18→17 |
3342 independent reflections | 3 standard reflections every 97 reflections |
2017 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)] = 0.059 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.148 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0588P)2] where P = (Fo2 + 2Fc2)/3 |
3342 reflections | (Δ/σ)max = 0.001 |
295 parameters | Δρmax = 0.15 e Å−3 |
0 restraints | Δρmin = −0.21 e Å−3 |
Crystal data top
C12H16N2O2 | γ = 100.306 (7)° |
Mr = 220.27 | V = 1209.6 (2) Å3 |
Triclinic, P1 | Z = 4 |
a = 6.2647 (4) Å | Cu Kα radiation |
b = 12.2138 (10) Å | µ = 0.68 mm−1 |
c = 16.459 (2) Å | T = 294 K |
α = 101.137 (12)° | 0.50 × 0.12 × 0.08 mm |
β = 93.566 (9)° | |
Data collection top
Bruker P4 diffractometer | Rint = 0.043 |
4192 measured reflections | θmax = 58.9° |
3342 independent reflections | 3 standard reflections every 97 reflections |
2017 reflections with I > 2σ(I) | intensity decay: none |
Refinement top
R[F2 > 2σ(F2)] = 0.059 | 0 restraints |
wR(F2) = 0.148 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.15 e Å−3 |
3342 reflections | Δρmin = −0.21 e Å−3 |
295 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 | x | y | z | Uiso*/Ueq | |
O1A | 0.9358 (4) | 0.6454 (2) | 0.34741 (17) | 0.0779 (9) | |
O2A | 0.0714 (4) | 0.57646 (19) | 0.13600 (16) | 0.0635 (7) | |
O1B | 0.0544 (5) | 0.1584 (2) | 0.16727 (18) | 0.0903 (10) | |
O2B | 0.6299 (4) | −0.0220 (2) | 0.40106 (16) | 0.0746 (8) | |
N1A | 0.3314 (4) | 0.3734 (2) | 0.20183 (17) | 0.0537 (8) | |
H1AA | 0.2853 | 0.3009 | 0.1888 | 0.064* | |
N2A | 0.2521 (5) | 0.5483 (2) | 0.1781 (2) | 0.0649 (9) | |
N1B | 0.1230 (5) | −0.1531 (2) | 0.29288 (18) | 0.0602 (9) | |
H1BA | 0.0532 | −0.2200 | 0.2943 | 0.072* | |
N2B | 0.4456 (5) | −0.0190 (2) | 0.3476 (2) | 0.0731 (10) | |
C1A | 0.5233 (5) | 0.4092 (3) | 0.2528 (2) | 0.0449 (9) | |
C2A | 0.6292 (5) | 0.5178 (3) | 0.2765 (2) | 0.0497 (9) | |
H2AA | 0.5708 | 0.5750 | 0.2586 | 0.060* | |
C3A | 0.8311 (6) | 0.5468 (3) | 0.3290 (2) | 0.0544 (10) | |
C4A | 0.9177 (6) | 0.4549 (3) | 0.3609 (2) | 0.0577 (10) | |
H4AA | 0.9896 | 0.4863 | 0.4165 | 0.069* | |
H4AB | 1.0269 | 0.4311 | 0.3258 | 0.069* | |
C5A | 0.7460 (6) | 0.3502 (3) | 0.3638 (2) | 0.0561 (10) | |
C6A | 0.6109 (6) | 0.3138 (3) | 0.2795 (2) | 0.0549 (10) | |
H6AA | 0.7005 | 0.2839 | 0.2379 | 0.066* | |
H6AB | 0.4899 | 0.2531 | 0.2821 | 0.066* | |
C7A | 0.5984 (7) | 0.3792 (4) | 0.4320 (3) | 0.0909 (15) | |
H7AA | 0.6839 | 0.4023 | 0.4850 | 0.136* | |
H7AB | 0.4886 | 0.3135 | 0.4322 | 0.136* | |
H7AC | 0.5299 | 0.4401 | 0.4215 | 0.136* | |
C8A | 0.8595 (7) | 0.2552 (3) | 0.3808 (3) | 0.0965 (17) | |
H8AA | 0.9408 | 0.2783 | 0.4348 | 0.145* | |
H8AB | 0.9569 | 0.2397 | 0.3392 | 0.145* | |
H8AC | 0.7523 | 0.1878 | 0.3793 | 0.145* | |
C9A | 0.2015 (5) | 0.4381 (3) | 0.1684 (2) | 0.0454 (9) | |
C10A | −0.0008 (5) | 0.3910 (3) | 0.1215 (2) | 0.0502 (9) | |
H10A | −0.0677 | 0.3147 | 0.1064 | 0.060* | |
C11A | −0.0754 (6) | 0.4798 (3) | 0.1034 (2) | 0.0492 (9) | |
C12A | −0.2771 (6) | 0.4935 (3) | 0.0585 (2) | 0.0626 (11) | |
H12A | −0.3685 | 0.4202 | 0.0377 | 0.094* | |
H12B | −0.2408 | 0.5295 | 0.0129 | 0.094* | |
H12C | −0.3531 | 0.5398 | 0.0958 | 0.094* | |
C1B | 0.0214 (6) | −0.0961 (3) | 0.2438 (2) | 0.0503 (9) | |
C2B | 0.1014 (6) | 0.0093 (3) | 0.2320 (2) | 0.0583 (10) | |
H2BA | 0.2380 | 0.0473 | 0.2579 | 0.070* | |
C3B | −0.0181 (6) | 0.0635 (3) | 0.1812 (2) | 0.0617 (11) | |
C4B | −0.2466 (6) | 0.0040 (3) | 0.1453 (2) | 0.0655 (11) | |
H4BA | −0.2831 | 0.0300 | 0.0950 | 0.079* | |
H4BB | −0.3481 | 0.0252 | 0.1849 | 0.079* | |
C5B | −0.2748 (6) | −0.1243 (3) | 0.1247 (2) | 0.0548 (10) | |
C6B | −0.1969 (6) | −0.1619 (3) | 0.2024 (2) | 0.0566 (10) | |
H6BA | −0.3041 | −0.1544 | 0.2421 | 0.068* | |
H6BB | −0.1891 | −0.2418 | 0.1875 | 0.068* | |
C7B | −0.1446 (7) | −0.1622 (4) | 0.0526 (3) | 0.0824 (13) | |
H7BA | −0.1978 | −0.1391 | 0.0039 | 0.124* | |
H7BB | −0.1609 | −0.2436 | 0.0414 | 0.124* | |
H7BC | 0.0066 | −0.1280 | 0.0670 | 0.124* | |
C8B | −0.5160 (6) | −0.1777 (3) | 0.0998 (3) | 0.0806 (13) | |
H8BA | −0.5621 | −0.1594 | 0.0481 | 0.121* | |
H8BB | −0.6013 | −0.1483 | 0.1423 | 0.121* | |
H8BC | −0.5359 | −0.2588 | 0.0933 | 0.121* | |
C9B | 0.3223 (6) | −0.1193 (3) | 0.3409 (2) | 0.0534 (10) | |
C10B | 0.4146 (6) | −0.1879 (3) | 0.3867 (2) | 0.0619 (11) | |
H10B | 0.3562 | −0.2620 | 0.3906 | 0.074* | |
C11B | 0.6029 (6) | −0.1244 (3) | 0.4231 (2) | 0.0616 (11) | |
C12B | 0.7823 (6) | −0.1417 (3) | 0.4793 (2) | 0.0774 (13) | |
H12D | 0.7750 | −0.2217 | 0.4758 | 0.116* | |
H12E | 0.7684 | −0.1059 | 0.5355 | 0.116* | |
H12F | 0.9199 | −0.1087 | 0.4631 | 0.116* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1A | 0.0716 (19) | 0.0522 (16) | 0.099 (2) | −0.0191 (14) | −0.0265 (16) | 0.0294 (14) |
O2A | 0.0549 (16) | 0.0486 (14) | 0.0872 (19) | 0.0089 (13) | −0.0170 (15) | 0.0228 (13) |
O1B | 0.095 (2) | 0.0466 (15) | 0.121 (2) | −0.0166 (15) | −0.0359 (19) | 0.0419 (16) |
O2B | 0.0630 (18) | 0.0604 (16) | 0.094 (2) | −0.0093 (14) | −0.0262 (16) | 0.0313 (15) |
N1A | 0.0477 (18) | 0.0378 (15) | 0.070 (2) | −0.0042 (14) | −0.0161 (16) | 0.0173 (14) |
N2A | 0.055 (2) | 0.0491 (18) | 0.088 (2) | 0.0024 (15) | −0.0224 (18) | 0.0247 (17) |
N1B | 0.059 (2) | 0.0408 (16) | 0.077 (2) | −0.0074 (15) | −0.0093 (18) | 0.0261 (15) |
N2B | 0.059 (2) | 0.059 (2) | 0.096 (3) | −0.0069 (17) | −0.021 (2) | 0.0276 (18) |
C1A | 0.042 (2) | 0.0407 (19) | 0.051 (2) | 0.0020 (16) | −0.0065 (18) | 0.0142 (16) |
C2A | 0.049 (2) | 0.0406 (19) | 0.059 (2) | 0.0035 (17) | −0.0063 (19) | 0.0179 (17) |
C3A | 0.051 (2) | 0.048 (2) | 0.060 (2) | −0.0074 (18) | −0.002 (2) | 0.0188 (18) |
C4A | 0.050 (2) | 0.056 (2) | 0.062 (2) | −0.0058 (18) | −0.015 (2) | 0.0210 (19) |
C5A | 0.052 (2) | 0.053 (2) | 0.060 (2) | −0.0059 (18) | −0.015 (2) | 0.0243 (18) |
C6A | 0.055 (2) | 0.0423 (19) | 0.063 (2) | 0.0023 (17) | −0.015 (2) | 0.0143 (17) |
C7A | 0.087 (3) | 0.113 (4) | 0.070 (3) | −0.009 (3) | 0.002 (3) | 0.043 (3) |
C8A | 0.100 (4) | 0.058 (3) | 0.127 (4) | 0.005 (2) | −0.053 (3) | 0.041 (3) |
C9A | 0.040 (2) | 0.043 (2) | 0.054 (2) | 0.0066 (16) | −0.0028 (18) | 0.0173 (16) |
C10A | 0.047 (2) | 0.047 (2) | 0.054 (2) | −0.0005 (17) | −0.0064 (19) | 0.0156 (17) |
C11A | 0.045 (2) | 0.052 (2) | 0.051 (2) | 0.0056 (18) | −0.0025 (18) | 0.0166 (18) |
C12A | 0.055 (2) | 0.073 (3) | 0.064 (2) | 0.020 (2) | −0.009 (2) | 0.021 (2) |
C1B | 0.047 (2) | 0.0400 (19) | 0.062 (2) | 0.0006 (17) | −0.0024 (19) | 0.0164 (17) |
C2B | 0.055 (2) | 0.042 (2) | 0.076 (3) | −0.0007 (18) | −0.008 (2) | 0.0193 (19) |
C3B | 0.063 (3) | 0.042 (2) | 0.077 (3) | 0.0015 (19) | −0.011 (2) | 0.0172 (19) |
C4B | 0.057 (3) | 0.050 (2) | 0.088 (3) | 0.0080 (19) | −0.011 (2) | 0.019 (2) |
C5B | 0.049 (2) | 0.0424 (19) | 0.069 (3) | 0.0024 (17) | −0.006 (2) | 0.0110 (18) |
C6B | 0.050 (2) | 0.044 (2) | 0.071 (3) | −0.0047 (17) | 0.000 (2) | 0.0157 (18) |
C7B | 0.082 (3) | 0.082 (3) | 0.076 (3) | 0.010 (3) | 0.001 (3) | 0.008 (2) |
C8B | 0.056 (3) | 0.071 (3) | 0.106 (3) | −0.004 (2) | −0.019 (3) | 0.021 (2) |
C9B | 0.054 (2) | 0.043 (2) | 0.058 (2) | −0.0051 (18) | −0.006 (2) | 0.0149 (17) |
C10B | 0.060 (3) | 0.049 (2) | 0.075 (3) | −0.0047 (19) | −0.006 (2) | 0.0271 (19) |
C11B | 0.063 (3) | 0.056 (2) | 0.067 (3) | 0.004 (2) | −0.005 (2) | 0.027 (2) |
C12B | 0.069 (3) | 0.080 (3) | 0.082 (3) | 0.003 (2) | −0.012 (2) | 0.032 (2) |
Geometric parameters (Å, º) top
O1A—C3A | 1.235 (4) | C9A—C10A | 1.407 (4) |
O2A—C11A | 1.354 (4) | C10A—C11A | 1.331 (4) |
O2A—N2A | 1.419 (3) | C10A—H10A | 0.9300 |
O1B—C3B | 1.236 (4) | C11A—C12A | 1.475 (4) |
O2B—C11B | 1.353 (4) | C12A—H12A | 0.9600 |
O2B—N2B | 1.418 (4) | C12A—H12B | 0.9600 |
N1A—C1A | 1.373 (4) | C12A—H12C | 0.9600 |
N1A—C9A | 1.391 (4) | C1B—C2B | 1.351 (4) |
N1A—H1AA | 0.8600 | C1B—C6B | 1.503 (4) |
N2A—C9A | 1.302 (4) | C2B—C3B | 1.418 (5) |
N1B—C1B | 1.362 (4) | C2B—H2BA | 0.9300 |
N1B—C9B | 1.386 (4) | C3B—C4B | 1.512 (5) |
N1B—H1BA | 0.8600 | C4B—C5B | 1.513 (4) |
N2B—C9B | 1.306 (4) | C4B—H4BA | 0.9700 |
C1A—C2A | 1.344 (4) | C4B—H4BB | 0.9700 |
C1A—C6A | 1.499 (4) | C5B—C6B | 1.520 (4) |
C2A—C3A | 1.435 (4) | C5B—C7B | 1.528 (5) |
C2A—H2AA | 0.9300 | C5B—C8B | 1.531 (5) |
C3A—C4A | 1.496 (4) | C6B—H6BA | 0.9700 |
C4A—C5A | 1.527 (4) | C6B—H6BB | 0.9700 |
C4A—H4AA | 0.9700 | C7B—H7BA | 0.9600 |
C4A—H4AB | 0.9700 | C7B—H7BB | 0.9600 |
C5A—C6A | 1.524 (4) | C7B—H7BC | 0.9600 |
C5A—C8A | 1.526 (5) | C8B—H8BA | 0.9600 |
C5A—C7A | 1.527 (5) | C8B—H8BB | 0.9600 |
C6A—H6AA | 0.9700 | C8B—H8BC | 0.9600 |
C6A—H6AB | 0.9700 | C9B—C10B | 1.403 (5) |
C7A—H7AA | 0.9600 | C10B—C11B | 1.326 (5) |
C7A—H7AB | 0.9600 | C10B—H10B | 0.9300 |
C7A—H7AC | 0.9600 | C11B—C12B | 1.482 (5) |
C8A—H8AA | 0.9600 | C12B—H12D | 0.9600 |
C8A—H8AB | 0.9600 | C12B—H12E | 0.9600 |
C8A—H8AC | 0.9600 | C12B—H12F | 0.9600 |
| | | |
C11A—O2A—N2A | 109.0 (2) | C11A—C12A—H12B | 109.5 |
C11B—O2B—N2B | 109.0 (3) | H12A—C12A—H12B | 109.5 |
C1A—N1A—C9A | 128.9 (3) | C11A—C12A—H12C | 109.5 |
C1A—N1A—H1AA | 115.5 | H12A—C12A—H12C | 109.5 |
C9A—N1A—H1AA | 115.5 | H12B—C12A—H12C | 109.5 |
C9A—N2A—O2A | 103.8 (3) | C2B—C1B—N1B | 125.3 (3) |
C1B—N1B—C9B | 129.6 (3) | C2B—C1B—C6B | 121.3 (3) |
C1B—N1B—H1BA | 115.2 | N1B—C1B—C6B | 113.4 (3) |
C9B—N1B—H1BA | 115.2 | C1B—C2B—C3B | 121.6 (3) |
C9B—N2B—O2B | 103.7 (3) | C1B—C2B—H2BA | 119.2 |
C2A—C1A—N1A | 124.9 (3) | C3B—C2B—H2BA | 119.2 |
C2A—C1A—C6A | 121.7 (3) | O1B—C3B—C2B | 122.8 (3) |
N1A—C1A—C6A | 113.3 (3) | O1B—C3B—C4B | 118.9 (3) |
C1A—C2A—C3A | 120.8 (3) | C2B—C3B—C4B | 118.2 (3) |
C1A—C2A—H2AA | 119.6 | C3B—C4B—C5B | 113.3 (3) |
C3A—C2A—H2AA | 119.6 | C3B—C4B—H4BA | 108.9 |
O1A—C3A—C2A | 121.4 (3) | C5B—C4B—H4BA | 108.9 |
O1A—C3A—C4A | 119.5 (3) | C3B—C4B—H4BB | 108.9 |
C2A—C3A—C4A | 119.1 (3) | C5B—C4B—H4BB | 108.9 |
C3A—C4A—C5A | 114.8 (3) | H4BA—C4B—H4BB | 107.7 |
C3A—C4A—H4AA | 108.6 | C4B—C5B—C6B | 107.8 (3) |
C5A—C4A—H4AA | 108.6 | C4B—C5B—C7B | 110.6 (3) |
C3A—C4A—H4AB | 108.6 | C6B—C5B—C7B | 110.6 (3) |
C5A—C4A—H4AB | 108.6 | C4B—C5B—C8B | 109.7 (3) |
H4AA—C4A—H4AB | 107.5 | C6B—C5B—C8B | 109.4 (3) |
C6A—C5A—C8A | 110.2 (3) | C7B—C5B—C8B | 108.7 (3) |
C6A—C5A—C7A | 109.6 (3) | C1B—C6B—C5B | 114.4 (3) |
C8A—C5A—C7A | 109.9 (3) | C1B—C6B—H6BA | 108.6 |
C6A—C5A—C4A | 107.6 (3) | C5B—C6B—H6BA | 108.6 |
C8A—C5A—C4A | 109.3 (3) | C1B—C6B—H6BB | 108.6 |
C7A—C5A—C4A | 110.2 (3) | C5B—C6B—H6BB | 108.6 |
C1A—C6A—C5A | 113.0 (3) | H6BA—C6B—H6BB | 107.6 |
C1A—C6A—H6AA | 109.0 | C5B—C7B—H7BA | 109.5 |
C5A—C6A—H6AA | 109.0 | C5B—C7B—H7BB | 109.5 |
C1A—C6A—H6AB | 109.0 | H7BA—C7B—H7BB | 109.5 |
C5A—C6A—H6AB | 109.0 | C5B—C7B—H7BC | 109.5 |
H6AA—C6A—H6AB | 107.8 | H7BA—C7B—H7BC | 109.5 |
C5A—C7A—H7AA | 109.5 | H7BB—C7B—H7BC | 109.5 |
C5A—C7A—H7AB | 109.5 | C5B—C8B—H8BA | 109.5 |
H7AA—C7A—H7AB | 109.5 | C5B—C8B—H8BB | 109.5 |
C5A—C7A—H7AC | 109.5 | H8BA—C8B—H8BB | 109.5 |
H7AA—C7A—H7AC | 109.5 | C5B—C8B—H8BC | 109.5 |
H7AB—C7A—H7AC | 109.5 | H8BA—C8B—H8BC | 109.5 |
C5A—C8A—H8AA | 109.5 | H8BB—C8B—H8BC | 109.5 |
C5A—C8A—H8AB | 109.5 | N2B—C9B—N1B | 122.9 (3) |
H8AA—C8A—H8AB | 109.5 | N2B—C9B—C10B | 112.7 (3) |
C5A—C8A—H8AC | 109.5 | N1B—C9B—C10B | 124.3 (3) |
H8AA—C8A—H8AC | 109.5 | C11B—C10B—C9B | 105.2 (3) |
H8AB—C8A—H8AC | 109.5 | C11B—C10B—H10B | 127.4 |
N2A—C9A—N1A | 123.8 (3) | C9B—C10B—H10B | 127.4 |
N2A—C9A—C10A | 113.0 (3) | C10B—C11B—O2B | 109.4 (3) |
N1A—C9A—C10A | 123.2 (3) | C10B—C11B—C12B | 134.7 (3) |
C11A—C10A—C9A | 104.8 (3) | O2B—C11B—C12B | 116.0 (3) |
C11A—C10A—H10A | 127.6 | C11B—C12B—H12D | 109.5 |
C9A—C10A—H10A | 127.6 | C11B—C12B—H12E | 109.5 |
C10A—C11A—O2A | 109.4 (3) | H12D—C12B—H12E | 109.5 |
C10A—C11A—C12A | 134.2 (3) | C11B—C12B—H12F | 109.5 |
O2A—C11A—C12A | 116.4 (3) | H12D—C12B—H12F | 109.5 |
C11A—C12A—H12A | 109.5 | H12E—C12B—H12F | 109.5 |
| | | |
C11A—O2A—N2A—C9A | −0.3 (4) | N2A—O2A—C11A—C12A | 178.8 (3) |
C11B—O2B—N2B—C9B | −0.3 (4) | C9B—N1B—C1B—C2B | 0.3 (6) |
C9A—N1A—C1A—C2A | −4.1 (6) | C9B—N1B—C1B—C6B | −179.1 (3) |
C9A—N1A—C1A—C6A | 177.3 (3) | N1B—C1B—C2B—C3B | −178.5 (4) |
N1A—C1A—C2A—C3A | −178.9 (3) | C6B—C1B—C2B—C3B | 0.9 (6) |
C6A—C1A—C2A—C3A | −0.4 (5) | C1B—C2B—C3B—O1B | −177.5 (4) |
C1A—C2A—C3A—O1A | 176.0 (4) | C1B—C2B—C3B—C4B | 4.6 (6) |
C1A—C2A—C3A—C4A | −3.1 (5) | O1B—C3B—C4B—C5B | 148.6 (4) |
O1A—C3A—C4A—C5A | 157.6 (4) | C2B—C3B—C4B—C5B | −33.5 (5) |
C2A—C3A—C4A—C5A | −23.3 (5) | C3B—C4B—C5B—C6B | 53.5 (4) |
C3A—C4A—C5A—C6A | 49.3 (4) | C3B—C4B—C5B—C7B | −67.6 (4) |
C3A—C4A—C5A—C8A | 169.0 (3) | C3B—C4B—C5B—C8B | 172.5 (3) |
C3A—C4A—C5A—C7A | −70.1 (4) | C2B—C1B—C6B—C5B | 22.5 (5) |
C2A—C1A—C6A—C5A | 29.8 (5) | N1B—C1B—C6B—C5B | −158.0 (3) |
N1A—C1A—C6A—C5A | −151.5 (3) | C4B—C5B—C6B—C1B | −48.2 (4) |
C8A—C5A—C6A—C1A | −171.0 (3) | C7B—C5B—C6B—C1B | 72.8 (4) |
C7A—C5A—C6A—C1A | 67.9 (4) | C8B—C5B—C6B—C1B | −167.4 (3) |
C4A—C5A—C6A—C1A | −51.9 (4) | O2B—N2B—C9B—N1B | −179.5 (3) |
O2A—N2A—C9A—N1A | −178.3 (3) | O2B—N2B—C9B—C10B | −0.1 (4) |
O2A—N2A—C9A—C10A | 0.7 (4) | C1B—N1B—C9B—N2B | 2.1 (6) |
C1A—N1A—C9A—N2A | 3.6 (6) | C1B—N1B—C9B—C10B | −177.3 (4) |
C1A—N1A—C9A—C10A | −175.3 (3) | N2B—C9B—C10B—C11B | 0.4 (5) |
N2A—C9A—C10A—C11A | −0.9 (4) | N1B—C9B—C10B—C11B | 179.9 (4) |
N1A—C9A—C10A—C11A | 178.1 (3) | C9B—C10B—C11B—O2B | −0.6 (5) |
C9A—C10A—C11A—O2A | 0.6 (4) | C9B—C10B—C11B—C12B | −179.8 (4) |
C9A—C10A—C11A—C12A | −178.2 (4) | N2B—O2B—C11B—C10B | 0.6 (4) |
N2A—O2A—C11A—C10A | −0.2 (4) | N2B—O2B—C11B—C12B | −180.0 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1AA···O1B | 0.86 | 2.01 | 2.811 (3) | 154 |
N1B—H1BA···O1Ai | 0.86 | 2.05 | 2.862 (3) | 157 |
C2A—H2AA···N2A | 0.93 | 2.26 | 2.900 (4) | 125 |
C2B—H2BA···N2B | 0.93 | 2.26 | 2.898 (5) | 125 |
C10A—H10A···O1B | 0.93 | 2.53 | 3.148 (4) | 124 |
Symmetry code: (i) x−1, y−1, z. |
Experimental details
Crystal data |
Chemical formula | C12H16N2O2 |
Mr | 220.27 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 294 |
a, b, c (Å) | 6.2647 (4), 12.2138 (10), 16.459 (2) |
α, β, γ (°) | 101.137 (12), 93.566 (9), 100.306 (7) |
V (Å3) | 1209.6 (2) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.68 |
Crystal size (mm) | 0.50 × 0.12 × 0.08 |
|
Data collection |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4192, 3342, 2017 |
Rint | 0.043 |
θmax (°) | 58.9 |
(sin θ/λ)max (Å−1) | 0.556 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.059, 0.148, 1.02 |
No. of reflections | 3342 |
No. of parameters | 295 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.15, −0.21 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1AA···O1B | 0.86 | 2.01 | 2.811 (3) | 154 |
N1B—H1BA···O1Ai | 0.86 | 2.05 | 2.862 (3) | 157 |
C2A—H2AA···N2A | 0.93 | 2.26 | 2.900 (4) | 125 |
C2B—H2BA···N2B | 0.93 | 2.26 | 2.898 (5) | 125 |
C10A—H10A···O1B | 0.93 | 2.53 | 3.148 (4) | 124 |
Symmetry code: (i) x−1, y−1, z. |
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Our research on the anticonvulsant activity of the enaminones has been augmented by X-ray analysis (Kubicki & Codding, 1993; Laws et al., 1998; Foster et al., 1999; Kubicki et al., 2000; Eddington et al., 2002; Anderson et al., 2006; Hanson et al., 2006). Recently, our investigation has led to the evaluation of various isoxazoles, from which 5-methyl-3-(5-methylisoxazol-3-yl)cyclohex-2-enone, (I) (Hanson et al., 2006), and the title compound, (II), have emerged. Although structurally similar to (I) (Hanson et al., 2006), compound (II) was exclusively MES (maximal electroshock seizure evaluation) active and more toxic (3/7 animals protected at 100 mg kg−1 at 30 min, 4/5 animals protected at 300 mg kg−1 at 30 min and at 4 h; toxicity evaluation: 2/8 toxic at 100 mg kg−1 at 30 min, 3/4 toxic at 300 mg kg−1 at 30 min and 1/2 toxic at 300 mg kg−1 at 4 h). Single-crystal X-ray analyses carried out on (I) (Hanson et al., 2006) and (II) (this work) point to the importance of intramolecular hydrogen bonding.
The structure of (II) is shown in Fig. 1. There are two structurally similar molecules, A and B, in the asymmetric unit. In agreement with our previous studies, hydrogen bonding occurs between the vinyl H atom and the aromatic/heterocyclic ring system (Fig. 2). In (II), this bonding occurs between the H atoms on atoms C2A and C2B and the lone pairs on atoms N2A and N2B on the isoxazole rings. Geometric parameters for this compound are similar to those observed in other related enaminones (Kubicki & Codding, 1993; Laws et al., 1998; Foster et al., 1999; Kubicki et al., 2002 Or 2000?; Eddington et al., 2002; Anderson et al., 2006; Hanson et al., 2006).
Compared with the packing arrangement in (I) (Hanson et al., 2006), a more complicated structural configuration occurs in the dimethyl analogue, (II). This compound is assembled as a head-to-tail dimer, exhibiting both intramolecular hydrogen bonding (C2B···N2B and N2A···C2A) and intermolecular hydrogen bonding with the carbonyl O atom (atom O1B and the isoxazole H atom on atom C10A, and the H atom on the secondary amine atom N1A), producing a pocket between these molecules. Furthermore, this clathrate conformation effectively blocks access to the proposed active site by virtue of the dimethyl substituents at both ends of the pocket. Pauling (1961, 1964a,b) proposed a molecular theory of general anesthesia, which involved the formation of minute hydrate crystals of the clathrate type that would interfere with nerve impulses. In the structure of (II), a clathrate has, in fact, been shown to occur which, if present in solution, could explain the toxicity of (II).