The title compound, C
14H
8N
4O
6, a new 1,2,5-oxadiazole
N-oxide derivative, was formed by dimerization of 4-nitrobenzaldehyde oxime. The compound crystallizes with two independent molecules per asymmetric unit. The
N-oxide O atom is disordered over two sites in each molecule; site occupancy factors are 0.57/0.43 and 0.5/0.5. The mean planes through the two benzene rings are inclined to the planar 1,2,3-oxadiazole ring by 25.03 (11) and 41.64 (11)° in one molecule, and 22.58 (11) and 42.66 (11)° in the other molecule, the smaller angle being for the ring on the oxide side of the oxadiazole ring in each case. In the crystal structure, the individual molecules form centrosymmetric dimers linked
via C—H
O hydrogen bonds. The dimers of one molecule are then linked to those of the other molecule
via C—H
O hydrogen bonds, forming a three-dimensional network.
Supporting information
CCDC reference: 677643
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.003 Å
- Disorder in main residue
- R factor = 0.060
- wR factor = 0.133
- Data-to-parameter ratio = 16.2
checkCIF/PLATON results
No syntax errors found
Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for O21B - N22 .. 8.69 su
PLAT432_ALERT_2_B Short Inter X...Y Contact O21B .. C22 .. 2.77 Ang.
PLAT432_ALERT_2_B Short Inter X...Y Contact C2 .. O1B .. 2.72 Ang.
Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for O2 - N1 .. 6.72 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for O22 - N21 .. 6.33 su
PLAT301_ALERT_3_C Main Residue Disorder ......................... 4.00 Perc.
PLAT432_ALERT_2_C Short Inter X...Y Contact C3 .. O1B .. 3.01 Ang.
0 ALERT level A = In general: serious problem
3 ALERT level B = Potentially serious problem
4 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
6 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
0 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
checkCIF publication errors
Alert level A
PUBL024_ALERT_1_A The number of authors is greater than 5.
Please specify the role of each of the co-authors
for your paper.
| Author Response: ...There are two groups in Moroccoo involved in this research and
the title compound has been produced by them on various occasions.
|
1 ALERT level A = Data missing that is essential or data in wrong format
0 ALERT level G = General alerts. Data that may be required is missing
The reaction of 4-nitrobenzaldehyde oxime with pure NaOCl, in a 2:1 molar ratio,
in CHCl3 (but never CH2Cl2) gives an almost quantitative yield of (II)
(95%), on stirring at room temperature for 16 h. Yellow block-like crystals
suitable for X-ray analysis were obtained by slow evaporation of an ethanol
solution of (II).
The N-oxide O-atom is disordered over two sites in each molecule (1 & 2); the
occupancies were finally fixed at O1a/O1b = 0.57/0.43 and
O31a/O31b = 0.5/0.5. The hydrogen atoms could all be located
from difference Fourier maps. They were included in calculated positons and
treated as riding atoms with C—H distances = 0.95 Å and Uiso(H) =
1.2Ueq(parent C-atom).
Data collection: X-AREA (Stoe & Cie, 2006); cell refinement: X-AREA (Stoe & Cie, 2006); data reduction: X-RED32 (Stoe & Cie, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
3,4-Bis(4-nitrophenyl)-1,2,5-oxadiazole 2-oxide
top
Crystal data top
C14H8N4O6 | F(000) = 1344 |
Mr = 328.24 | Dx = 1.599 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 22316 reflections |
a = 17.3977 (11) Å | θ = 1.4–29.6° |
b = 7.2813 (4) Å | µ = 0.13 mm−1 |
c = 21.5341 (13) Å | T = 173 K |
β = 91.667 (5)° | Block, yellow |
V = 2726.7 (3) Å3 | 0.40 × 0.35 × 0.30 mm |
Z = 8 | |
Data collection top
Stoe IPDS-2 diffractometer | 5558 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.054 |
Graphite monochromator | θmax = 29.3°, θmin = 1.9° |
Detector resolution: 6.67 pixels mm-1 | h = −23→23 |
ϕ and ω scans | k = −9→9 |
29047 measured reflections | l = −29→27 |
7339 independent reflections | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.060 | H-atom parameters constrained |
wR(F2) = 0.133 | w = 1/[σ2(Fo2) + (0.0291P)2 + 1.6814P] where P = (Fo2 + 2Fc2)/3 |
S = 1.15 | (Δ/σ)max = 0.001 |
7339 reflections | Δρmax = 0.22 e Å−3 |
452 parameters | Δρmin = −0.17 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0064 (7) |
Crystal data top
C14H8N4O6 | V = 2726.7 (3) Å3 |
Mr = 328.24 | Z = 8 |
Monoclinic, P21/c | Mo Kα radiation |
a = 17.3977 (11) Å | µ = 0.13 mm−1 |
b = 7.2813 (4) Å | T = 173 K |
c = 21.5341 (13) Å | 0.40 × 0.35 × 0.30 mm |
β = 91.667 (5)° | |
Data collection top
Stoe IPDS-2 diffractometer | 5558 reflections with I > 2σ(I) |
29047 measured reflections | Rint = 0.054 |
7339 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.060 | 0 restraints |
wR(F2) = 0.133 | H-atom parameters constrained |
S = 1.15 | Δρmax = 0.22 e Å−3 |
7339 reflections | Δρmin = −0.17 e Å−3 |
452 parameters | |
Special details top
Geometry. Bond distances, angles etc. have been calculated using the rounded
fractional coordinates. All su's are estimated from the variances of the
(full) variance-covariance matrix. The cell e.s.d.'s are taken into account in
the estimation of distances, angles and torsion angles |
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 | Occ. (<1) |
O1A | −0.20064 (15) | 1.0812 (5) | 0.33132 (14) | 0.0569 (10) | 0.570 |
O1B | −0.0065 (2) | 1.3687 (5) | 0.26989 (17) | 0.0467 (12) | 0.430 |
O2 | −0.11135 (10) | 1.2492 (2) | 0.29646 (8) | 0.0559 (6) | |
O3 | 0.34176 (9) | 0.9789 (2) | 0.41298 (8) | 0.0532 (6) | |
O4 | 0.35733 (9) | 1.0989 (3) | 0.32312 (9) | 0.0613 (6) | |
O5 | −0.16080 (10) | 0.2648 (3) | 0.48002 (10) | 0.0649 (7) | |
O6 | −0.03872 (10) | 0.2186 (2) | 0.47351 (8) | 0.0533 (6) | |
N1 | −0.13345 (11) | 1.0918 (3) | 0.32958 (9) | 0.0482 (6) | |
N2 | −0.03118 (11) | 1.2504 (3) | 0.29531 (9) | 0.0458 (6) | |
N3 | 0.31689 (10) | 1.0437 (2) | 0.36429 (9) | 0.0408 (5) | |
N4 | −0.09605 (11) | 0.3130 (3) | 0.46617 (8) | 0.0435 (6) | |
C1 | −0.07019 (11) | 1.0052 (3) | 0.34783 (9) | 0.0374 (6) | |
C2 | −0.00587 (12) | 1.1062 (3) | 0.32676 (9) | 0.0376 (6) | |
C3 | 0.07736 (11) | 1.0830 (3) | 0.33666 (9) | 0.0350 (6) | |
C4 | 0.10802 (12) | 1.0318 (3) | 0.39460 (9) | 0.0384 (6) | |
C5 | 0.18658 (11) | 1.0173 (3) | 0.40352 (10) | 0.0378 (6) | |
C6 | 0.23332 (11) | 1.0561 (3) | 0.35481 (10) | 0.0359 (6) | |
C7 | 0.20455 (12) | 1.1079 (3) | 0.29709 (10) | 0.0403 (6) | |
C8 | 0.12612 (12) | 1.1209 (3) | 0.28824 (10) | 0.0403 (6) | |
C9 | −0.07511 (11) | 0.8297 (3) | 0.38100 (9) | 0.0359 (6) | |
C10 | −0.14024 (12) | 0.7885 (3) | 0.41433 (10) | 0.0442 (7) | |
C11 | −0.14705 (12) | 0.6194 (3) | 0.44269 (11) | 0.0449 (7) | |
C12 | −0.08802 (12) | 0.4955 (3) | 0.43814 (9) | 0.0384 (6) | |
C13 | −0.02201 (11) | 0.5341 (3) | 0.40691 (10) | 0.0382 (6) | |
C14 | −0.01649 (11) | 0.7014 (3) | 0.37723 (9) | 0.0373 (6) | |
O21A | 0.29246 (18) | 1.1020 (5) | 0.16767 (16) | 0.0578 (13) | 0.500 |
O21B | 0.49456 (18) | 1.3863 (4) | 0.22893 (14) | 0.0461 (10) | 0.500 |
O22 | 0.38508 (9) | 1.2667 (2) | 0.20230 (8) | 0.0542 (6) | |
O23 | 0.85144 (9) | 1.0823 (3) | 0.17637 (9) | 0.0620 (7) | |
O24 | 0.82849 (10) | 0.9729 (3) | 0.08579 (9) | 0.0597 (6) | |
O25 | 0.31736 (10) | 0.2800 (2) | 0.02256 (9) | 0.0582 (6) | |
O26 | 0.44007 (10) | 0.2367 (2) | 0.02397 (8) | 0.0537 (6) | |
N21 | 0.36029 (11) | 1.1097 (3) | 0.17004 (9) | 0.0464 (6) | |
N22 | 0.46569 (11) | 1.2675 (3) | 0.20255 (9) | 0.0445 (6) | |
N23 | 0.80723 (10) | 1.0366 (2) | 0.13458 (9) | 0.0420 (6) | |
N24 | 0.38324 (11) | 0.3300 (3) | 0.03385 (8) | 0.0425 (6) | |
C21 | 0.42189 (11) | 1.0222 (3) | 0.15133 (9) | 0.0367 (6) | |
C22 | 0.48800 (11) | 1.1233 (3) | 0.17116 (9) | 0.0366 (6) | |
C23 | 0.57059 (11) | 1.0973 (3) | 0.16113 (9) | 0.0351 (6) | |
C24 | 0.59670 (11) | 1.0453 (3) | 0.10327 (9) | 0.0378 (6) | |
C25 | 0.67416 (12) | 1.0243 (3) | 0.09420 (10) | 0.0384 (6) | |
C26 | 0.72470 (11) | 1.0581 (3) | 0.14354 (10) | 0.0361 (6) | |
C27 | 0.70047 (12) | 1.1111 (3) | 0.20112 (10) | 0.0396 (6) | |
C28 | 0.62323 (12) | 1.1303 (3) | 0.20988 (9) | 0.0391 (6) | |
C29 | 0.41346 (11) | 0.8464 (3) | 0.11884 (9) | 0.0359 (6) | |
C30 | 0.34415 (12) | 0.8024 (3) | 0.08826 (10) | 0.0449 (7) | |
C31 | 0.33437 (12) | 0.6338 (3) | 0.06037 (11) | 0.0452 (7) | |
C32 | 0.39471 (12) | 0.5119 (3) | 0.06177 (9) | 0.0380 (6) | |
C33 | 0.46440 (11) | 0.5523 (3) | 0.09033 (10) | 0.0387 (6) | |
C34 | 0.47300 (11) | 0.7196 (3) | 0.11986 (10) | 0.0375 (6) | |
H4 | 0.07490 | 1.00690 | 0.42790 | 0.0460* | |
H7 | 0.23810 | 1.13390 | 0.26420 | 0.0480* | |
H8 | 0.10510 | 1.15590 | 0.24880 | 0.0480* | |
H10 | −0.18010 | 0.87690 | 0.41760 | 0.0530* | |
H11 | −0.19170 | 0.58940 | 0.46490 | 0.0540* | |
H13 | 0.01880 | 0.44760 | 0.40580 | 0.0460* | |
H14 | 0.02770 | 0.72880 | 0.35410 | 0.0450* | |
H5 | 0.20810 | 0.98100 | 0.44270 | 0.0450* | |
H24 | 0.56090 | 1.02430 | 0.06990 | 0.0450* | |
H25 | 0.69240 | 0.98750 | 0.05500 | 0.0460* | |
H27 | 0.73660 | 1.13390 | 0.23410 | 0.0480* | |
H28 | 0.60550 | 1.16630 | 0.24940 | 0.0470* | |
H30 | 0.30350 | 0.88940 | 0.08670 | 0.0540* | |
H31 | 0.28670 | 0.60220 | 0.04050 | 0.0540* | |
H33 | 0.50570 | 0.46700 | 0.08970 | 0.0460* | |
H34 | 0.52010 | 0.74810 | 0.14110 | 0.0450* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1A | 0.0354 (14) | 0.080 (2) | 0.0549 (17) | 0.0116 (14) | −0.0039 (12) | 0.0144 (15) |
O1B | 0.054 (2) | 0.042 (2) | 0.044 (2) | 0.0035 (16) | 0.0018 (16) | 0.0160 (16) |
O2 | 0.0530 (10) | 0.0577 (11) | 0.0558 (10) | 0.0170 (8) | −0.0162 (8) | 0.0003 (8) |
O3 | 0.0414 (8) | 0.0630 (11) | 0.0547 (10) | 0.0061 (8) | −0.0064 (7) | 0.0046 (8) |
O4 | 0.0396 (9) | 0.0799 (13) | 0.0647 (11) | −0.0101 (8) | 0.0077 (8) | 0.0087 (10) |
O5 | 0.0531 (10) | 0.0581 (11) | 0.0836 (13) | −0.0183 (9) | 0.0061 (9) | 0.0106 (10) |
O6 | 0.0598 (10) | 0.0446 (9) | 0.0553 (10) | 0.0018 (8) | −0.0015 (8) | 0.0031 (7) |
N1 | 0.0411 (10) | 0.0575 (12) | 0.0454 (10) | 0.0076 (9) | −0.0081 (8) | −0.0004 (9) |
N2 | 0.0463 (10) | 0.0458 (11) | 0.0445 (10) | 0.0058 (8) | −0.0100 (8) | 0.0011 (9) |
N3 | 0.0367 (9) | 0.0356 (9) | 0.0501 (10) | −0.0017 (7) | −0.0009 (8) | −0.0050 (8) |
N4 | 0.0467 (10) | 0.0430 (10) | 0.0406 (9) | −0.0107 (8) | −0.0025 (8) | −0.0041 (8) |
C1 | 0.0344 (10) | 0.0432 (11) | 0.0342 (10) | 0.0044 (8) | −0.0047 (7) | −0.0030 (8) |
C2 | 0.0396 (10) | 0.0394 (11) | 0.0334 (10) | 0.0023 (8) | −0.0049 (8) | −0.0012 (8) |
C3 | 0.0350 (10) | 0.0319 (10) | 0.0379 (10) | −0.0039 (8) | −0.0036 (8) | 0.0014 (8) |
C4 | 0.0388 (10) | 0.0399 (11) | 0.0365 (10) | −0.0040 (8) | −0.0007 (8) | 0.0027 (8) |
C5 | 0.0382 (10) | 0.0376 (11) | 0.0374 (10) | −0.0017 (8) | −0.0044 (8) | 0.0020 (8) |
C6 | 0.0342 (9) | 0.0285 (9) | 0.0450 (11) | −0.0025 (8) | −0.0009 (8) | −0.0034 (8) |
C7 | 0.0403 (11) | 0.0396 (11) | 0.0412 (11) | −0.0049 (9) | 0.0033 (8) | 0.0022 (9) |
C8 | 0.0417 (11) | 0.0397 (11) | 0.0393 (11) | −0.0041 (9) | −0.0030 (8) | 0.0051 (9) |
C9 | 0.0310 (9) | 0.0428 (11) | 0.0337 (9) | −0.0030 (8) | −0.0030 (7) | −0.0022 (8) |
C10 | 0.0351 (10) | 0.0493 (13) | 0.0485 (12) | 0.0030 (9) | 0.0047 (9) | 0.0019 (10) |
C11 | 0.0355 (10) | 0.0519 (13) | 0.0475 (12) | −0.0038 (9) | 0.0056 (9) | 0.0012 (10) |
C12 | 0.0394 (10) | 0.0391 (11) | 0.0364 (10) | −0.0069 (8) | −0.0036 (8) | −0.0023 (8) |
C13 | 0.0344 (10) | 0.0379 (10) | 0.0419 (11) | −0.0026 (8) | −0.0033 (8) | −0.0048 (9) |
C14 | 0.0331 (10) | 0.0404 (11) | 0.0383 (10) | −0.0041 (8) | 0.0005 (8) | −0.0037 (8) |
O21A | 0.0357 (16) | 0.078 (3) | 0.060 (2) | 0.0089 (16) | 0.0076 (14) | −0.0136 (18) |
O21B | 0.0495 (17) | 0.0430 (17) | 0.0459 (17) | −0.0024 (14) | 0.0008 (13) | −0.0184 (14) |
O22 | 0.0515 (9) | 0.0603 (11) | 0.0514 (9) | 0.0154 (8) | 0.0136 (7) | −0.0062 (8) |
O23 | 0.0375 (8) | 0.0833 (14) | 0.0650 (11) | −0.0078 (9) | −0.0038 (8) | −0.0061 (10) |
O24 | 0.0454 (9) | 0.0716 (12) | 0.0628 (11) | 0.0054 (8) | 0.0119 (8) | −0.0120 (9) |
O25 | 0.0519 (10) | 0.0559 (11) | 0.0669 (11) | −0.0174 (8) | 0.0022 (8) | −0.0114 (9) |
O26 | 0.0573 (10) | 0.0465 (9) | 0.0572 (10) | 0.0029 (8) | 0.0022 (8) | −0.0064 (8) |
N21 | 0.0406 (10) | 0.0574 (12) | 0.0414 (10) | 0.0057 (9) | 0.0070 (7) | −0.0025 (9) |
N22 | 0.0470 (10) | 0.0452 (11) | 0.0416 (10) | 0.0037 (8) | 0.0085 (8) | −0.0041 (8) |
N23 | 0.0386 (9) | 0.0359 (9) | 0.0516 (11) | −0.0028 (7) | 0.0045 (8) | 0.0039 (8) |
N24 | 0.0481 (10) | 0.0408 (10) | 0.0386 (9) | −0.0057 (8) | 0.0037 (8) | 0.0020 (8) |
C21 | 0.0334 (9) | 0.0439 (11) | 0.0331 (9) | 0.0015 (8) | 0.0041 (7) | −0.0002 (8) |
C22 | 0.0372 (10) | 0.0397 (11) | 0.0331 (9) | 0.0008 (8) | 0.0050 (7) | −0.0004 (8) |
C23 | 0.0371 (10) | 0.0309 (10) | 0.0375 (10) | −0.0038 (8) | 0.0036 (8) | −0.0006 (8) |
C24 | 0.0379 (10) | 0.0374 (10) | 0.0380 (10) | −0.0030 (8) | 0.0015 (8) | −0.0029 (8) |
C25 | 0.0414 (11) | 0.0367 (10) | 0.0375 (10) | −0.0023 (8) | 0.0058 (8) | −0.0039 (8) |
C26 | 0.0371 (10) | 0.0280 (9) | 0.0433 (11) | −0.0036 (8) | 0.0040 (8) | 0.0021 (8) |
C27 | 0.0402 (11) | 0.0384 (11) | 0.0401 (11) | −0.0061 (9) | −0.0022 (8) | −0.0006 (9) |
C28 | 0.0422 (11) | 0.0397 (11) | 0.0354 (10) | −0.0053 (9) | 0.0036 (8) | −0.0030 (8) |
C29 | 0.0319 (9) | 0.0415 (11) | 0.0343 (9) | −0.0019 (8) | 0.0038 (7) | 0.0012 (8) |
C30 | 0.0357 (10) | 0.0499 (13) | 0.0488 (12) | 0.0062 (9) | −0.0046 (9) | −0.0042 (10) |
C31 | 0.0338 (10) | 0.0525 (13) | 0.0488 (12) | −0.0026 (9) | −0.0064 (9) | −0.0063 (10) |
C32 | 0.0395 (10) | 0.0400 (11) | 0.0346 (10) | −0.0054 (8) | 0.0041 (8) | 0.0006 (8) |
C33 | 0.0324 (9) | 0.0385 (11) | 0.0454 (11) | −0.0013 (8) | 0.0045 (8) | 0.0032 (9) |
C34 | 0.0291 (9) | 0.0412 (11) | 0.0421 (11) | −0.0049 (8) | 0.0005 (8) | 0.0026 (9) |
Geometric parameters (Å, º) top
O1A—N1 | 1.173 (3) | C10—C11 | 1.381 (3) |
O1B—N2 | 1.113 (4) | C11—C12 | 1.373 (3) |
O2—N2 | 1.396 (3) | C12—C13 | 1.377 (3) |
O2—N1 | 1.409 (3) | C13—C14 | 1.380 (3) |
O3—N3 | 1.218 (2) | C4—H4 | 0.9500 |
O4—N3 | 1.216 (3) | C5—H5 | 0.9500 |
O5—N4 | 1.225 (3) | C7—H7 | 0.9500 |
O6—N4 | 1.218 (3) | C8—H8 | 0.9500 |
O21A—N21 | 1.181 (4) | C10—H10 | 0.9500 |
O21B—N22 | 1.143 (4) | C11—H11 | 0.9500 |
O22—N21 | 1.399 (3) | C13—H13 | 0.9500 |
O22—N22 | 1.402 (2) | C14—H14 | 0.9500 |
O23—N23 | 1.213 (3) | C21—C22 | 1.421 (3) |
O24—N23 | 1.216 (3) | C21—C29 | 1.464 (3) |
O25—N24 | 1.220 (3) | C22—C23 | 1.471 (3) |
O26—N24 | 1.223 (3) | C23—C24 | 1.391 (3) |
N1—C1 | 1.318 (3) | C23—C28 | 1.394 (3) |
N2—C2 | 1.318 (3) | C24—C25 | 1.376 (3) |
N3—C6 | 1.465 (3) | C25—C26 | 1.381 (3) |
N4—C12 | 1.468 (3) | C26—C27 | 1.376 (3) |
N21—C21 | 1.320 (3) | C27—C28 | 1.370 (3) |
N22—C22 | 1.314 (3) | C29—C30 | 1.394 (3) |
N23—C26 | 1.463 (3) | C29—C34 | 1.387 (3) |
N24—C32 | 1.466 (3) | C30—C31 | 1.375 (3) |
C1—C9 | 1.468 (3) | C31—C32 | 1.374 (3) |
C1—C2 | 1.424 (3) | C32—C33 | 1.375 (3) |
C2—C3 | 1.467 (3) | C33—C34 | 1.380 (3) |
C3—C8 | 1.391 (3) | C24—H24 | 0.9500 |
C3—C4 | 1.393 (3) | C25—H25 | 0.9500 |
C4—C5 | 1.379 (3) | C27—H27 | 0.9500 |
C5—C6 | 1.375 (3) | C28—H28 | 0.9500 |
C6—C7 | 1.379 (3) | C30—H30 | 0.9500 |
C7—C8 | 1.376 (3) | C31—H31 | 0.9500 |
C9—C10 | 1.392 (3) | C33—H33 | 0.9500 |
C9—C14 | 1.387 (3) | C34—H34 | 0.9500 |
| | | |
N1—O2—N2 | 107.55 (16) | C6—C5—H5 | 121.00 |
N21—O22—N22 | 107.40 (16) | C8—C7—H7 | 121.00 |
O1A—N1—O2 | 110.9 (2) | C6—C7—H7 | 121.00 |
O2—N1—C1 | 107.59 (17) | C7—C8—H8 | 120.00 |
O1A—N1—C1 | 141.5 (3) | C3—C8—H8 | 120.00 |
O2—N2—C2 | 107.76 (18) | C11—C10—H10 | 120.00 |
O1B—N2—O2 | 114.4 (2) | C9—C10—H10 | 120.00 |
O1B—N2—C2 | 137.8 (3) | C10—C11—H11 | 121.00 |
O3—N3—O4 | 123.86 (18) | C12—C11—H11 | 121.00 |
O3—N3—C6 | 118.05 (17) | C14—C13—H13 | 121.00 |
O4—N3—C6 | 118.09 (18) | C12—C13—H13 | 121.00 |
O5—N4—C12 | 117.3 (2) | C13—C14—H14 | 120.00 |
O6—N4—C12 | 118.49 (18) | C9—C14—H14 | 120.00 |
O5—N4—O6 | 124.2 (2) | N21—C21—C22 | 108.40 (19) |
O22—N21—C21 | 107.74 (17) | N21—C21—C29 | 119.80 (18) |
O21A—N21—O22 | 110.7 (2) | C22—C21—C29 | 131.73 (18) |
O21A—N21—C21 | 141.6 (3) | N22—C22—C21 | 108.67 (18) |
O21B—N22—C22 | 136.8 (2) | N22—C22—C23 | 118.87 (19) |
O22—N22—C22 | 107.77 (17) | C21—C22—C23 | 132.43 (19) |
O21B—N22—O22 | 115.5 (2) | C22—C23—C24 | 120.81 (17) |
O23—N23—O24 | 122.91 (19) | C22—C23—C28 | 119.36 (18) |
O23—N23—C26 | 118.45 (18) | C24—C23—C28 | 119.80 (18) |
O24—N23—C26 | 118.64 (18) | C23—C24—C25 | 120.27 (18) |
O25—N24—O26 | 124.0 (2) | C24—C25—C26 | 118.37 (19) |
O26—N24—C32 | 118.17 (18) | N23—C26—C25 | 119.00 (19) |
O25—N24—C32 | 117.85 (18) | N23—C26—C27 | 118.45 (18) |
N1—C1—C9 | 120.10 (18) | C25—C26—C27 | 122.55 (19) |
C2—C1—C9 | 131.46 (18) | C26—C27—C28 | 118.70 (19) |
N1—C1—C2 | 108.35 (19) | C23—C28—C27 | 120.30 (19) |
N2—C2—C3 | 118.68 (19) | C21—C29—C30 | 119.99 (18) |
C1—C2—C3 | 132.49 (19) | C21—C29—C34 | 120.66 (18) |
N2—C2—C1 | 108.73 (18) | C30—C29—C34 | 119.3 (2) |
C4—C3—C8 | 119.90 (18) | C29—C30—C31 | 120.4 (2) |
C2—C3—C4 | 120.76 (18) | C30—C31—C32 | 118.8 (2) |
C2—C3—C8 | 119.28 (18) | N24—C32—C31 | 118.67 (19) |
C3—C4—C5 | 119.83 (19) | N24—C32—C33 | 118.98 (19) |
C4—C5—C6 | 118.94 (19) | C31—C32—C33 | 122.3 (2) |
N3—C6—C5 | 119.18 (19) | C32—C33—C34 | 118.50 (19) |
N3—C6—C7 | 118.37 (18) | C29—C34—C33 | 120.61 (18) |
C5—C6—C7 | 122.45 (19) | C23—C24—H24 | 120.00 |
C6—C7—C8 | 118.45 (19) | C25—C24—H24 | 120.00 |
C3—C8—C7 | 120.4 (2) | C24—C25—H25 | 121.00 |
C1—C9—C10 | 119.91 (18) | C26—C25—H25 | 121.00 |
C1—C9—C14 | 120.30 (18) | C26—C27—H27 | 121.00 |
C10—C9—C14 | 119.7 (2) | C28—C27—H27 | 121.00 |
C9—C10—C11 | 120.1 (2) | C23—C28—H28 | 120.00 |
C10—C11—C12 | 118.7 (2) | C27—C28—H28 | 120.00 |
C11—C12—C13 | 122.5 (2) | C29—C30—H30 | 120.00 |
N4—C12—C13 | 118.45 (19) | C31—C30—H30 | 120.00 |
N4—C12—C11 | 119.03 (19) | C30—C31—H31 | 121.00 |
C12—C13—C14 | 118.47 (19) | C32—C31—H31 | 121.00 |
C9—C14—C13 | 120.40 (18) | C32—C33—H33 | 121.00 |
C3—C4—H4 | 120.00 | C34—C33—H33 | 121.00 |
C5—C4—H4 | 120.00 | C29—C34—H34 | 120.00 |
C4—C5—H5 | 121.00 | C33—C34—H34 | 120.00 |
| | | |
N2—O2—N1—O1A | −178.8 (2) | C4—C3—C8—C7 | 0.1 (3) |
N2—O2—N1—C1 | 0.7 (2) | C2—C3—C4—C5 | −177.6 (2) |
N1—O2—N2—C2 | −1.4 (2) | C3—C4—C5—C6 | 0.8 (3) |
N22—O22—N21—O21A | −179.3 (2) | C4—C5—C6—C7 | −0.5 (3) |
N22—O22—N21—C21 | −0.7 (2) | C4—C5—C6—N3 | 179.06 (19) |
N21—O22—N22—O21B | −178.0 (2) | C5—C6—C7—C8 | 0.0 (3) |
N21—O22—N22—C22 | 1.5 (2) | N3—C6—C7—C8 | −179.54 (19) |
O2—N1—C1—C9 | −176.89 (17) | C6—C7—C8—C3 | 0.2 (3) |
O1A—N1—C1—C2 | 179.5 (4) | C14—C9—C10—C11 | −1.1 (3) |
O1A—N1—C1—C9 | 2.4 (5) | C1—C9—C14—C13 | −178.11 (19) |
O2—N1—C1—C2 | 0.1 (2) | C1—C9—C10—C11 | 176.3 (2) |
O2—N2—C2—C3 | −175.41 (17) | C10—C9—C14—C13 | −0.7 (3) |
O2—N2—C2—C1 | 1.4 (2) | C9—C10—C11—C12 | 1.1 (3) |
O3—N3—C6—C5 | 8.3 (3) | C10—C11—C12—N4 | −177.74 (19) |
O3—N3—C6—C7 | −172.13 (19) | C10—C11—C12—C13 | 0.7 (3) |
O4—N3—C6—C5 | −171.6 (2) | C11—C12—C13—C14 | −2.4 (3) |
O4—N3—C6—C7 | 8.0 (3) | N4—C12—C13—C14 | 175.99 (18) |
O5—N4—C12—C11 | 16.0 (3) | C12—C13—C14—C9 | 2.4 (3) |
O6—N4—C12—C11 | −164.9 (2) | N21—C21—C22—N22 | 1.4 (2) |
O6—N4—C12—C13 | 16.7 (3) | N21—C21—C22—C23 | −176.5 (2) |
O5—N4—C12—C13 | −162.5 (2) | C29—C21—C22—N22 | −175.4 (2) |
O22—N21—C21—C22 | −0.4 (2) | C29—C21—C22—C23 | 6.8 (4) |
O21A—N21—C21—C22 | 177.6 (4) | N21—C21—C29—C30 | 23.0 (3) |
O21A—N21—C21—C29 | −5.2 (5) | N21—C21—C29—C34 | −154.8 (2) |
O22—N21—C21—C29 | 176.84 (17) | C22—C21—C29—C30 | −160.6 (2) |
O21B—N22—C22—C23 | −4.2 (4) | C22—C21—C29—C34 | 21.6 (3) |
O21B—N22—C22—C21 | 177.6 (3) | N22—C22—C23—C24 | −135.9 (2) |
O22—N22—C22—C21 | −1.7 (2) | N22—C22—C23—C28 | 42.3 (3) |
O22—N22—C22—C23 | 176.42 (17) | C21—C22—C23—C24 | 41.7 (3) |
O24—N23—C26—C25 | −6.9 (3) | C21—C22—C23—C28 | −140.1 (2) |
O23—N23—C26—C25 | 173.5 (2) | C22—C23—C24—C25 | 179.0 (2) |
O23—N23—C26—C27 | −6.6 (3) | C28—C23—C24—C25 | 0.8 (3) |
O24—N23—C26—C27 | 173.0 (2) | C22—C23—C28—C27 | −178.5 (2) |
O25—N24—C32—C33 | 162.4 (2) | C24—C23—C28—C27 | −0.2 (3) |
O25—N24—C32—C31 | −15.3 (3) | C23—C24—C25—C26 | −0.7 (3) |
O26—N24—C32—C31 | 165.6 (2) | C24—C25—C26—N23 | −179.92 (19) |
O26—N24—C32—C33 | −16.7 (3) | C24—C25—C26—C27 | 0.2 (3) |
N1—C1—C2—N2 | −1.0 (2) | N23—C26—C27—C28 | −179.59 (19) |
N1—C1—C9—C14 | 152.1 (2) | C25—C26—C27—C28 | 0.3 (3) |
C2—C1—C9—C10 | 158.6 (2) | C26—C27—C28—C23 | −0.3 (3) |
C2—C1—C9—C14 | −24.1 (3) | C21—C29—C30—C31 | −176.6 (2) |
C9—C1—C2—C3 | −8.2 (4) | C34—C29—C30—C31 | 1.2 (3) |
N1—C1—C2—C3 | 175.2 (2) | C21—C29—C34—C33 | 178.61 (19) |
C9—C1—C2—N2 | 175.6 (2) | C30—C29—C34—C33 | 0.8 (3) |
N1—C1—C9—C10 | −25.2 (3) | C29—C30—C31—C32 | −1.7 (3) |
N2—C2—C3—C4 | 135.9 (2) | C30—C31—C32—N24 | 177.95 (19) |
N2—C2—C3—C8 | −41.2 (3) | C30—C31—C32—C33 | 0.3 (3) |
C1—C2—C3—C4 | −40.1 (3) | N24—C32—C33—C34 | −175.98 (19) |
C1—C2—C3—C8 | 142.9 (2) | C31—C32—C33—C34 | 1.7 (3) |
C8—C3—C4—C5 | −0.6 (3) | C32—C33—C34—C29 | −2.2 (3) |
C2—C3—C8—C7 | 177.2 (2) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C5—H5···O5i | 0.95 | 2.59 | 3.283 (3) | 130 |
C7—H7···O21A | 0.95 | 2.32 | 3.218 (4) | 157 |
C10—H10···O1A | 0.95 | 2.40 | 2.955 (4) | 117 |
C14—H14···O23ii | 0.95 | 2.46 | 3.244 (3) | 139 |
C25—H25···O25iii | 0.95 | 2.57 | 3.358 (3) | 141 |
C27—H27···O1Aiv | 0.95 | 2.36 | 3.254 (4) | 156 |
C28—H28···O21B | 0.95 | 2.54 | 2.951 (4) | 106 |
C30—H30···O21A | 0.95 | 2.34 | 2.929 (4) | 119 |
C31—H31···O5v | 0.95 | 2.52 | 3.261 (3) | 135 |
C34—H34···O4ii | 0.95 | 2.50 | 3.284 (3) | 140 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+1, −y+1, −z; (iv) x+1, y, z; (v) −x, y+1/2, −z+1/2. |
Experimental details
Crystal data |
Chemical formula | C14H8N4O6 |
Mr | 328.24 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 17.3977 (11), 7.2813 (4), 21.5341 (13) |
β (°) | 91.667 (5) |
V (Å3) | 2726.7 (3) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.13 |
Crystal size (mm) | 0.40 × 0.35 × 0.30 |
|
Data collection |
Diffractometer | Stoe IPDS2 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 29047, 7339, 5558 |
Rint | 0.054 |
(sin θ/λ)max (Å−1) | 0.688 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.060, 0.133, 1.15 |
No. of reflections | 7339 |
No. of parameters | 452 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.17 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C5—H5···O5i | 0.95 | 2.59 | 3.283 (3) | 130 |
C14—H14···O23ii | 0.95 | 2.46 | 3.244 (3) | 139 |
C25—H25···O25iii | 0.95 | 2.57 | 3.358 (3) | 141 |
C27—H27···O1Aiv | 0.95 | 2.36 | 3.254 (4) | 156 |
C31—H31···O5v | 0.95 | 2.52 | 3.261 (3) | 135 |
C34—H34···O4ii | 0.95 | 2.50 | 3.284 (3) | 140 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+1, −y+1, −z; (iv) x+1, y, z; (v) −x, y+1/2, −z+1/2. |
In the course of our research aimed at the synthesis of new efficient antitubercular agents containing simple pharmacophore sites of the type X—C—C—Y we turned our attention to the spiro-isoxazolines which posses a rigid (O=C—C—O) pharmacophore. These compounds display interesting biological properties, such as herbicidal, plant-growth regulatory and antitumor activities (Howe & Shelton, 1990; Smietana et al., 1999). The preparation of the spiro-isoxazolines, in which we are interested, normally involves the reaction of a nitriloxyde [(E)-4-nitrobenzaldehyde oxime, (I)] with an isothiochromanone in a solution of hydrogen peroxyde (Kerbal et al., 1990). We have noted many times the formation of a by-product during this reaction. Finally this compound has been isolated and examined crystallographically. It was found to be a new 1,2,5-oxadiazole N-oxide derivative, (II).
The molecular structure of compound (II) is shown in Fig. 1. The compound crystallizes with two independent molecules (1 & 2) per asymmetric unit. The 1,2,5-oxadiazole units are disordered with two alternative positions for the N-oxide O-atom [atom O1a/O1b in molecule 1, and atom O21a/O21b in molecule 2]. There are some short intramolecular C···O contacts in the two molecules involving the disordered atoms; O1b and neighbouring C-atoms C2 and C3, and atom O21b with atom C22. A search of the Cambridge Crystallographic Data Base (Version 1.8, last update May 2007: Allen, 2002) indicates that such short interactions are not unusual. The 1,2,5-oxadiazole ring is planar [to within 0.008 and 0.009 Å, in molecules 1 and 2, respectively] and the bond distances and angles are similar to those in the diphenyl analoque 3,4-Diphenylfurazan N-oxide, (III) [Sillitoe & Harding, 1978)]. They do not indicate the presence of delocalized electron density as in the dichlorophenyl analoque 4,5-bis(2,6-Dichlorophenyl)-1-oxide-2-oxa-1,3-diazole, (IV) [Easton et al., 1995] or a D-mannose-derived furoxan [Baker et al., 2002]. The C?N bonds being significantly shorter than the C—C or O—N bonds. The remainder of the bond distances in (II) are within normal limits (Allen et al., 1987). The best planes through the phenyl rings are inclined to the best plane through the 1,2,5-oxadiazole ring by 25.03 (11) and 41.64 (11)° in molecule 1, and 22.58 (11) and 42.66 (11)° in molecule 2. This is quite different to the situation in (III), where the same dihedral angles are 16.7 and 59.6°, or in (IV), where the same dihedral angles are 63.1 (3) and 65.6 (5)°.
In the crystal structure of (II) the individual molecules are linked to their symmetry related molecule via C—H···O hydrogen bonds to form centrosynmetric dimers. These dimers are in turn linked by other C—H···O hydrogen bonds to form a three-dimensional network. Details of the hydrogen bonding are given in Table 1 and Fig. 2.
The formation of compound (II) is similar to that described by Baker et al. (2002), who have studied in detail the synthesis and X-ray structure of 3,4-dipyranosyl-1,2,5-oxadiazole 2-oxide. Similarly we found that the reaction of 4-nitrobenzaldehyde oxime with pure NaOCl in CHCl3, but never CH2Cl2, gives an almost quantitative yield of (II) (95%), on simply stirring at room temperature for 16 h.