Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104017743/bm1572sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104017743/bm1572I-Esup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104017743/bm1572I-Zsup3.hkl |
CCDC references: 254926; 254927
Propenoic acid derivatives (I—Z) and (I—E) were obtained by the reaction between equimolar quantities (1.0 mmol) of maleic anhydride and 2-aminophenol dissolved in tetrahydrofuran (THF). Ac2O (0.1 mmol) was added as catalyst, and after heating at 323–328 K for 2 h, isomer (I—Z) was obtained. Under the same conditions, but heating at 343 K for 3 h, isomer (I—E) was obtained. In both cases, THF was removed by evaporation and the resulting solid was treated with aqueous HCl (5%) until precipitation was complete. After washing three times with deionized water and drying, the product was recrystallized from ethanol solutions to give crystals suitable for X-ray analysis in approximately 70% yield. For (I—E), m.p. 500–502 K; IR (KBr, cm−1): ν 1710 (COO), 1527 (C=N); 1H NMR: δ 13.2 (b, 1H, OH), 7.84 (d, 1H, 3J = 8.6 Hz, H4), 7.77 (d, 1H, 3J = 8.6 Hz, H7), 7.52 (dd, 1H, 3J = 8.6 Hz, H6), 7.45 (d, 1H, 3J = 15.8 Hz, H10), 7.44 (dd, 1H, 3J = 8.6 Hz, H5), 6.92 (d, 1H, 3J = 15.8 and 15.8 Hz, H11); 13C NMR: δ 166.0 (C12), 159.9 (C2), 150.1 (C8), 141.4 (C-9), 129.3 (C11), 128.2 (C10), 126.9 (C6), 125.2 (C5), 120.5 (C4), 111.1 (C7). For (I—Z), m.p. 396–397 K; IR (KBr, cm−1): ν 1707 (COO), 1527 (C=N); 1H NMR: δ 13.2 (b, 1H, OH), 7.8 (dd, 1H, 3J = 8.5 Hz, 4J = 1.2 Hz, H4), 7.7 (dd, 1H, 3J = 8.0 Hz, 4J = 1.3 Hz, H7), 7.4 (ddd, 1H, 3J = 8.6 Hz, 4J = 1.3 Hz, H6), 7.5 (ddd, 1H, 3J = 8.6 Hz, 4J = 1.3 Hz, H5), 6.88 (d, 1H, 3J = 12.0 Hz, H10), 6.66 (d, 1H, 3J = 12.0 Hz, H11); 13C NMR: δ 167.0 (C12), 159.6 (C2), 149.8 (C8), 140.1 (C9), 132.3 (C11), 120.0 (C10), 126.3 (C6), 125.1 (C5), 120.1 (C4), 111.0 (C7).
All H atoms were refined as riding on their parent atoms using SHELXL97 (Sheldrick, 1997) defaults [O—H = 0.82 Å, C—H = 0.9298–0.9301 Å and Uiso(H) = 1.2Ueq(C,O)] ##AUTHOR: Specify the X—H distances applied, and also the treatment of the Uiso values for H atoms. Here is an example from a different structure: # The NH H atoms were refined freely. Methyl H atoms attached to # sp2 centres were located from difference Fourier syntheses and # refined as part of rigid rotating groups with C—H distances fixed # at 0.96 Å and Uiso(H) = 1.5Ueq(C). Other hydrogen atoms were # introduced at geometrically calculated positions and refined using # a riding model with fixed C—H bond lengths of 0.95 Å (sp2 C—H) # or 0.99 Å (methylenes), and with Uiso(H) = 1.2Ueq(C).
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1992) for I-E; SMART (Bruker, 2000) for I-Z. Cell refinement: CAD-4 EXPRESS for I-E; SMART for I-Z. Data reduction: JANA98 (Vaclav, 1998) for I-E; SAINT (Bruker, 2000) for I-Z. For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997). Molecular graphics: WinGX (Farrugia, 1999) for I-E; SHELXTL (Bruker, 2000) for I-Z. Software used to prepare material for publication: SHELXL97 for I-E; SHELXL97 and WinGX2003 (Farrugia, 1999) for I-Z.
C10H7NO3 | F(000) = 392 |
Mr = 189.17 | Dx = 1.449 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 24 reflections |
a = 5.882 (1) Å | θ = 10–11° |
b = 19.694 (1) Å | µ = 0.11 mm−1 |
c = 7.4910 (1) Å | T = 293 K |
β = 91.715 (10)° | Block, yellow |
V = 867.37 (15) Å3 | 0.50 × 0.50 × 0.40 mm |
Z = 4 |
Enraf–Nonius CAD-4 diffractometer | 1554 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.011 |
Graphite monochromator | θmax = 28.0°, θmin = 2.9° |
Detector resolution: 3 pixels mm-1 | h = −7→7 |
ω/2θ scans | k = 0→25 |
2082 measured reflections | l = 0→9 |
2082 independent reflections |
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)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.124 | H-atom parameters constrained |
S = 1.15 | w = 1/[σ2(Fo2) + (0.058P)2 + 0.105P] where P = (Fo2 + 2Fc2)/3 |
2082 reflections | (Δ/σ)max = 0.001 |
128 parameters | Δρmax = 0.19 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C10H7NO3 | V = 867.37 (15) Å3 |
Mr = 189.17 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 5.882 (1) Å | µ = 0.11 mm−1 |
b = 19.694 (1) Å | T = 293 K |
c = 7.4910 (1) Å | 0.50 × 0.50 × 0.40 mm |
β = 91.715 (10)° |
Enraf–Nonius CAD-4 diffractometer | 1554 reflections with I > 2σ(I) |
2082 measured reflections | Rint = 0.011 |
2082 independent reflections |
R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
wR(F2) = 0.124 | H-atom parameters constrained |
S = 1.15 | Δρmax = 0.19 e Å−3 |
2082 reflections | Δρmin = −0.18 e Å−3 |
128 parameters |
Experimental. Diffractometer operator Susana Rojas Lima scanwidth_degrees 0.7 low_scanspeed_degrees/min 16.1 high_scanspeed_degrees/min 60 Background measurement: Moving crystal and moving counter at the beginning and end of scan, each for 25% of total scan area. Crystal mounted on a glass fiber. Melting points were measured on a Gallen-Kamp MFB-595 apparatus and are uncorrected. IR spectra were recorded as KBr discs using a Perkin-Elmer 16 F PC IR spectrophotometer. 1H and 13C NMR spectra were recorded with a Jeol Eclipse (1H, 270.17; 13 C, 67.94 MHz) instrument in CDCl3 solutions, using SiMe4 as internal reference and following standard techniques. |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'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. |
x | y | z | Uiso*/Ueq | ||
O1' | 0.19143 (16) | 0.07791 (5) | 0.12194 (13) | 0.0441 (3) | |
O1A | −0.29352 (19) | 0.26311 (5) | −0.11302 (17) | 0.0577 (4) | |
O1B | −0.0045 (2) | 0.32487 (6) | −0.00237 (17) | 0.0641 (4) | |
N3' | 0.50902 (19) | 0.12704 (6) | 0.23255 (15) | 0.0422 (4) | |
C1 | −0.0947 (3) | 0.27108 (7) | −0.0281 (2) | 0.0441 (4) | |
C2 | 0.0031 (3) | 0.20497 (7) | 0.02673 (19) | 0.0457 (4) | |
C2' | 0.3106 (2) | 0.13587 (7) | 0.15533 (18) | 0.0403 (4) | |
C3 | 0.2083 (2) | 0.19981 (7) | 0.10092 (19) | 0.0439 (4) | |
C4' | 0.7046 (3) | 0.01690 (8) | 0.3240 (2) | 0.0499 (5) | |
C5' | 0.6701 (3) | −0.05243 (9) | 0.3223 (2) | 0.0565 (5) | |
C6' | 0.4693 (3) | −0.08116 (8) | 0.2545 (2) | 0.0576 (5) | |
C7' | 0.2940 (3) | −0.04194 (8) | 0.1836 (2) | 0.0523 (5) | |
C8' | 0.3332 (2) | 0.02687 (7) | 0.18488 (17) | 0.0411 (4) | |
C9' | 0.5296 (2) | 0.05681 (7) | 0.25275 (18) | 0.0401 (4) | |
H1A | −0.33657 | 0.29971 | −0.15382 | 0.0693* | |
H2 | −0.08278 | 0.16580 | 0.00838 | 0.0548* | |
H3 | 0.29201 | 0.23937 | 0.11937 | 0.0526* | |
H4' | 0.83836 | 0.03594 | 0.37056 | 0.0599* | |
H5' | 0.78435 | −0.08075 | 0.36770 | 0.0677* | |
H6' | 0.45266 | −0.12810 | 0.25704 | 0.0691* | |
H7' | 0.15924 | −0.06075 | 0.13820 | 0.0627* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1' | 0.0382 (5) | 0.0384 (5) | 0.0550 (6) | −0.0016 (4) | −0.0122 (4) | −0.0024 (4) |
O1A | 0.0458 (6) | 0.0433 (6) | 0.0825 (8) | −0.0007 (5) | −0.0233 (5) | 0.0109 (5) |
O1B | 0.0646 (7) | 0.0390 (6) | 0.0869 (8) | −0.0044 (5) | −0.0257 (6) | −0.0010 (5) |
N3' | 0.0362 (6) | 0.0403 (6) | 0.0495 (7) | −0.0010 (5) | −0.0084 (5) | −0.0012 (5) |
C1 | 0.0426 (7) | 0.0389 (7) | 0.0503 (8) | 0.0006 (6) | −0.0076 (6) | 0.0009 (5) |
C2 | 0.0443 (7) | 0.0372 (7) | 0.0548 (8) | −0.0006 (6) | −0.0106 (6) | 0.0005 (6) |
C2' | 0.0367 (7) | 0.0388 (7) | 0.0449 (7) | −0.0019 (5) | −0.0059 (5) | −0.0031 (5) |
C3 | 0.0425 (7) | 0.0374 (7) | 0.0513 (7) | −0.0008 (5) | −0.0070 (6) | −0.0017 (6) |
C4' | 0.0416 (7) | 0.0554 (9) | 0.0524 (8) | 0.0069 (6) | −0.0047 (6) | 0.0051 (7) |
C5' | 0.0588 (10) | 0.0547 (9) | 0.0560 (9) | 0.0185 (8) | 0.0029 (7) | 0.0098 (7) |
C6' | 0.0729 (11) | 0.0396 (8) | 0.0604 (9) | 0.0056 (7) | 0.0057 (8) | 0.0027 (7) |
C7' | 0.0559 (9) | 0.0414 (8) | 0.0593 (9) | −0.0047 (7) | −0.0033 (7) | −0.0046 (6) |
C8' | 0.0413 (7) | 0.0392 (7) | 0.0425 (7) | 0.0019 (5) | −0.0033 (5) | −0.0021 (5) |
C9' | 0.0375 (7) | 0.0420 (7) | 0.0407 (6) | 0.0016 (5) | −0.0025 (5) | −0.0001 (5) |
O1'—C2' | 1.3588 (17) | C4'—C5' | 1.380 (2) |
O1'—C8' | 1.3800 (16) | C5'—C6' | 1.392 (2) |
O1A—C1 | 1.324 (2) | C6'—C7' | 1.382 (2) |
O1B—C1 | 1.1978 (19) | C7'—C8' | 1.375 (2) |
O1A—H1A | 0.8200 | C8'—C9' | 1.3804 (18) |
N3'—C2' | 1.2987 (17) | C2—H2 | 0.9300 |
N3'—C9' | 1.3962 (18) | C3—H3 | 0.9298 |
C1—C2 | 1.477 (2) | C4'—H4' | 0.9300 |
C2—C3 | 1.318 (2) | C5'—H5' | 0.9299 |
C2'—C3 | 1.4489 (19) | C6'—H6' | 0.9299 |
C4'—C9' | 1.389 (2) | C7'—H7' | 0.9301 |
O1A···C2i | 3.317 (2) | C5'···O1Bix | 3.372 (2) |
O1A···N3'ii | 2.6995 (16) | C5'···C4'viii | 3.566 (2) |
O1B···C3i | 3.295 (2) | C6'···C2'vii | 3.536 (2) |
O1B···C2'i | 3.3004 (19) | C6'···C4'viii | 3.579 (2) |
O1B···C5'iii | 3.372 (2) | C7'···C8'vii | 3.589 (2) |
O1'···H2 | 2.4978 | C7'···C9'vii | 3.471 (2) |
O1'···H7'iv | 2.8152 | C8'···C7'vii | 3.589 (2) |
O1B···H5'iii | 2.4640 | C9'···C7'vii | 3.471 (2) |
O1B···H3 | 2.5717 | C9'···C5'viii | 3.427 (2) |
N3'···O1Av | 2.6995 (16) | C2'···H1Av | 2.7898 |
N3'···H1Av | 1.8932 | C7'···H2iv | 3.0749 |
C1···C2i | 3.433 (2) | C9'···H1Av | 3.0102 |
C1···C3i | 3.395 (2) | H1A···N3'ii | 1.8932 |
C2···O1Avi | 3.317 (2) | H1A···C2'ii | 2.7898 |
C2···C1vi | 3.433 (2) | H1A···C9'ii | 3.0102 |
C2'···C6'vii | 3.536 (2) | H2···O1' | 2.4978 |
C2'···O1Bvi | 3.3004 (19) | H2···C7'iv | 3.0749 |
C3···O1Bvi | 3.295 (2) | H2···H7'iv | 2.3788 |
C3···C1vi | 3.395 (2) | H3···O1B | 2.5717 |
C4'···C5'viii | 3.566 (2) | H5'···O1Bix | 2.4640 |
C4'···C6'viii | 3.579 (2) | H7'···O1'iv | 2.8152 |
C5'···C9'viii | 3.427 (2) | H7'···H2iv | 2.3788 |
C2'—O1'—C8' | 104.23 (10) | O1'—C8'—C7' | 128.04 (12) |
C1—O1A—H1A | 109.47 | N3'—C9'—C8' | 108.32 (11) |
C2'—N3'—C9' | 104.76 (11) | C4'—C9'—C8' | 120.15 (13) |
O1A—C1—C2 | 111.12 (12) | N3'—C9'—C4' | 131.53 (12) |
O1B—C1—C2 | 124.61 (16) | C1—C2—H2 | 119.00 |
O1A—C1—O1B | 124.25 (14) | C3—C2—H2 | 119.01 |
C1—C2—C3 | 121.98 (14) | C2—C3—H3 | 118.19 |
O1'—C2'—C3 | 118.08 (11) | C2'—C3—H3 | 118.22 |
N3'—C2'—C3 | 127.00 (12) | C5'—C4'—H4' | 121.65 |
O1'—C2'—N3' | 114.92 (12) | C9'—C4'—H4' | 121.66 |
C2—C3—C2' | 123.59 (13) | C4'—C5'—H5' | 119.04 |
C5'—C4'—C9' | 116.69 (15) | C6'—C5'—H5' | 119.06 |
C4'—C5'—C6' | 121.90 (16) | C5'—C6'—H6' | 119.04 |
C5'—C6'—C7' | 121.90 (15) | C7'—C6'—H6' | 119.07 |
C6'—C7'—C8' | 115.17 (15) | C6'—C7'—H7' | 122.41 |
O1'—C8'—C9' | 107.77 (12) | C8'—C7'—H7' | 122.42 |
C7'—C8'—C9' | 124.20 (13) | ||
C8'—O1'—C2'—N3' | −0.41 (15) | N3'—C2'—C3—C2 | −178.33 (14) |
C2'—O1'—C8'—C7' | 180.00 (17) | C5'—C4'—C9'—N3' | −179.50 (14) |
C2'—O1'—C8'—C9' | 0.04 (14) | C5'—C4'—C9'—C8' | 0.0 (2) |
C8'—O1'—C2'—C3 | 178.85 (11) | C9'—C4'—C5'—C6' | −0.7 (2) |
C9'—N3'—C2'—O1' | 0.59 (15) | C4'—C5'—C6'—C7' | 0.6 (2) |
C2'—N3'—C9'—C4' | 179.06 (15) | C5'—C6'—C7'—C8' | 0.1 (2) |
C2'—N3'—C9'—C8' | −0.52 (15) | C6'—C7'—C8'—C9' | −0.8 (2) |
C9'—N3'—C2'—C3 | −178.60 (13) | C6'—C7'—C8'—O1' | 179.29 (13) |
O1A—C1—C2—C3 | 174.58 (14) | O1'—C8'—C9'—C4' | −179.35 (12) |
O1B—C1—C2—C3 | −4.1 (3) | C7'—C8'—C9'—N3' | −179.64 (13) |
C1—C2—C3—C2' | −179.56 (13) | C7'—C8'—C9'—C4' | 0.7 (2) |
O1'—C2'—C3—C2 | 2.5 (2) | O1'—C8'—C9'—N3' | 0.29 (14) |
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) x−1, −y+1/2, z−1/2; (iii) −x+1, y+1/2, −z+1/2; (iv) −x, −y, −z; (v) x+1, −y+1/2, z+1/2; (vi) x, −y+1/2, z+1/2; (vii) −x+1, −y, −z; (viii) −x+1, −y, −z+1; (ix) −x+1, y−1/2, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1A—H1A···N3′ii | 0.82 | 1.89 | 2.6995 (16) | 167 |
C2—H2···O1′ | 0.93 | 2.50 | 2.8196 (18) | 100 |
C5′—H5′···O1Bix | 0.93 | 2.46 | 3.372 (2) | 165 |
Symmetry codes: (ii) x−1, −y+1/2, z−1/2; (ix) −x+1, y−1/2, −z+1/2. |
C10H7NO3 | F(000) = 784 |
Mr = 189.17 | Dx = 1.414 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 1010 reflections |
a = 9.8191 (19) Å | θ = 1.6–32.0° |
b = 9.905 (2) Å | µ = 0.11 mm−1 |
c = 18.320 (4) Å | T = 293 K |
β = 94.037 (4)° | Block, yellow |
V = 1777.4 (6) Å3 | 0.36 × 0.21 × 0.19 mm |
Z = 8 |
Bruker SMART area-detector diffractometer | Rint = 0.035 |
Graphite monochromator | θmax = 27.5°, θmin = 2.2° |
ϕ and ω scans | h = −12→12 |
9736 measured reflections | k = −12→12 |
2013 independent reflections | l = −23→23 |
1559 reflections with I > 2σ(I) |
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)] = 0.053 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H-atom parameters constrained |
S = 1.05 | w = 1/[σ2(Fo2) + (0.045P)2 + 1.031P] where P = (Fo2 + 2Fc2)/3 |
2013 reflections | (Δ/σ)max < 0.001 |
128 parameters | Δρmax = 0.23 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C10H7NO3 | V = 1777.4 (6) Å3 |
Mr = 189.17 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 9.8191 (19) Å | µ = 0.11 mm−1 |
b = 9.905 (2) Å | T = 293 K |
c = 18.320 (4) Å | 0.36 × 0.21 × 0.19 mm |
β = 94.037 (4)° |
Bruker SMART area-detector diffractometer | 1559 reflections with I > 2σ(I) |
9736 measured reflections | Rint = 0.035 |
2013 independent reflections |
R[F2 > 2σ(F2)] = 0.053 | 0 restraints |
wR(F2) = 0.127 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.23 e Å−3 |
2013 reflections | Δρmin = −0.18 e Å−3 |
128 parameters |
Experimental. Diffractometer operator H. Höpfl scanwidth_degrees 0.7 low_scanspeed_degrees/min 16.1 high_scanspeed_degrees/min 60 Background measurement: Moving crystal and moving counter at the beginning and end of scan, each for 25% of total scan area. Crystal mounted on a glass fiber. |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'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. |
x | y | z | Uiso*/Ueq | ||
O1' | 0.22231 (13) | 0.47504 (12) | 0.05292 (7) | 0.0486 (4) | |
O1A | 0.48568 (14) | 0.57351 (13) | 0.13708 (8) | 0.0615 (5) | |
O1B | 0.33365 (18) | 0.71816 (15) | 0.17534 (9) | 0.0801 (6) | |
N3' | 0.11006 (14) | 0.28418 (15) | 0.07418 (9) | 0.0482 (5) | |
C1 | 0.3773 (2) | 0.60559 (19) | 0.17063 (10) | 0.0488 (6) | |
C2 | 0.3145 (2) | 0.4896 (2) | 0.20736 (10) | 0.0538 (7) | |
C2' | 0.18735 (18) | 0.38027 (17) | 0.10189 (10) | 0.0455 (6) | |
C3 | 0.2335 (2) | 0.39429 (19) | 0.17792 (10) | 0.0522 (6) | |
C4' | 0.0151 (2) | 0.2510 (2) | −0.05751 (13) | 0.0645 (8) | |
C5' | 0.0144 (2) | 0.3112 (3) | −0.12498 (14) | 0.0748 (9) | |
C6' | 0.0841 (2) | 0.4301 (3) | −0.13600 (12) | 0.0710 (9) | |
C7' | 0.1591 (2) | 0.4950 (2) | −0.08002 (11) | 0.0599 (7) | |
C8' | 0.15859 (18) | 0.43348 (19) | −0.01291 (10) | 0.0463 (6) | |
C9' | 0.08944 (18) | 0.31515 (19) | −0.00027 (11) | 0.0481 (6) | |
H1A | 0.51842 | 0.64177 | 0.12002 | 0.0738* | |
H2 | 0.33476 | 0.48313 | 0.25759 | 0.0645* | |
H3 | 0.20327 | 0.32945 | 0.20973 | 0.0627* | |
H4' | −0.03199 | 0.17117 | −0.05044 | 0.0774* | |
H5' | −0.03436 | 0.27086 | −0.16452 | 0.0898* | |
H6' | 0.08024 | 0.46736 | −0.18269 | 0.0852* | |
H7' | 0.20654 | 0.57467 | −0.08721 | 0.0719* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1' | 0.0533 (7) | 0.0395 (7) | 0.0540 (8) | −0.0028 (5) | 0.0104 (6) | 0.0039 (5) |
O1A | 0.0614 (9) | 0.0454 (8) | 0.0803 (10) | −0.0028 (7) | 0.0232 (7) | 0.0067 (7) |
O1B | 0.0997 (12) | 0.0521 (9) | 0.0929 (12) | 0.0068 (8) | 0.0371 (10) | −0.0028 (8) |
N3' | 0.0427 (8) | 0.0393 (8) | 0.0640 (10) | 0.0004 (7) | 0.0142 (7) | −0.0005 (7) |
C1 | 0.0562 (11) | 0.0468 (11) | 0.0433 (10) | −0.0030 (9) | 0.0037 (8) | −0.0051 (8) |
C2 | 0.0600 (12) | 0.0590 (12) | 0.0433 (10) | 0.0000 (10) | 0.0105 (8) | 0.0050 (9) |
C2' | 0.0442 (9) | 0.0373 (9) | 0.0565 (11) | 0.0019 (8) | 0.0150 (8) | 0.0044 (8) |
C3 | 0.0569 (11) | 0.0472 (10) | 0.0545 (11) | −0.0013 (9) | 0.0173 (9) | 0.0093 (9) |
C4' | 0.0487 (11) | 0.0621 (13) | 0.0823 (16) | 0.0029 (10) | 0.0025 (10) | −0.0165 (12) |
C5' | 0.0585 (13) | 0.0961 (19) | 0.0682 (15) | 0.0169 (13) | −0.0067 (11) | −0.0203 (13) |
C6' | 0.0613 (14) | 0.0942 (19) | 0.0571 (13) | 0.0239 (13) | 0.0019 (10) | 0.0049 (12) |
C7' | 0.0568 (12) | 0.0618 (13) | 0.0619 (12) | 0.0130 (10) | 0.0093 (10) | 0.0107 (10) |
C8' | 0.0419 (9) | 0.0449 (10) | 0.0527 (11) | 0.0097 (8) | 0.0070 (8) | −0.0013 (8) |
C9' | 0.0392 (9) | 0.0466 (10) | 0.0596 (12) | 0.0088 (8) | 0.0105 (8) | −0.0040 (9) |
O1'—C2' | 1.359 (2) | C4'—C5' | 1.372 (4) |
O1'—C8' | 1.382 (2) | C5'—C6' | 1.384 (4) |
O1A—C1 | 1.305 (2) | C6'—C7' | 1.379 (3) |
O1B—C1 | 1.200 (2) | C7'—C8' | 1.373 (3) |
O1A—H1A | 0.8199 | C8'—C9' | 1.382 (3) |
N3'—C2' | 1.298 (2) | C2—H2 | 0.9299 |
N3'—C9' | 1.399 (3) | C3—H3 | 0.9298 |
C1—C2 | 1.487 (3) | C4'—H4' | 0.9296 |
C2—C3 | 1.324 (3) | C5'—H5' | 0.9299 |
C2'—C3 | 1.441 (3) | C6'—H6' | 0.9299 |
C4'—C9' | 1.389 (3) | C7'—H7' | 0.9304 |
O1'···O1A | 3.075 (2) | C5'···C2'i | 3.490 (3) |
O1'···C1 | 2.859 (2) | C5'···C3i | 3.398 (3) |
O1'···C4'i | 3.411 (2) | C6'···C2'vi | 3.355 (3) |
O1A···O1' | 3.075 (2) | C7'···O1Biv | 3.338 (3) |
O1A···N3'ii | 2.715 (2) | C7'···N3'vi | 3.438 (3) |
O1B···C3iii | 3.310 (3) | C7'···C9'vi | 3.487 (3) |
O1B···C7'iv | 3.338 (3) | C8'···C9'vi | 3.503 (3) |
O1A···H2v | 2.6748 | C8'···C8'vi | 3.445 (3) |
O1B···H3iii | 2.4264 | C8'···N3'i | 3.380 (2) |
O1B···H7'iv | 2.6237 | C8'···C9'i | 3.487 (3) |
N3'···C7'vi | 3.438 (3) | C9'···C8'i | 3.487 (3) |
N3'···O1Avii | 2.715 (2) | C9'···C7'vi | 3.487 (3) |
N3'···C8'i | 3.380 (2) | C9'···C8'vi | 3.503 (3) |
N3'···H1Avii | 1.9003 | C9'···C9'i | 3.406 (3) |
C1···O1' | 2.859 (2) | C9'···C2'i | 3.548 (3) |
C2'···C6'vi | 3.355 (3) | C2'···H1Avii | 2.9189 |
C2'···C9'i | 3.548 (3) | C9'···H1Avii | 2.9169 |
C2'···C4'i | 3.350 (3) | H1A···N3'ii | 1.9003 |
C2'···C5'i | 3.490 (3) | H1A···C2'ii | 2.9189 |
C3···O1Bviii | 3.310 (3) | H1A···C9'ii | 2.9169 |
C3···C5'i | 3.398 (3) | H2···O1Av | 2.6748 |
C4'···C2'i | 3.350 (3) | H3···O1Bviii | 2.4264 |
C4'···O1'i | 3.411 (2) | H7'···O1Biv | 2.6237 |
C2'—O1'—C8' | 104.51 (13) | O1'—C8'—C7' | 128.29 (17) |
C1—O1A—H1A | 109.47 | N3'—C9'—C8' | 108.07 (16) |
C2'—N3'—C9' | 105.13 (15) | C4'—C9'—C8' | 119.99 (18) |
O1A—C1—C2 | 113.76 (16) | N3'—C9'—C4' | 131.94 (18) |
O1B—C1—C2 | 121.59 (18) | C1—C2—H2 | 115.75 |
O1A—C1—O1B | 124.57 (18) | C3—C2—H2 | 115.74 |
C1—C2—C3 | 128.51 (17) | C2—C3—H3 | 116.50 |
O1'—C2'—C3 | 119.65 (15) | C2'—C3—H3 | 116.54 |
N3'—C2'—C3 | 125.74 (17) | C5'—C4'—H4' | 121.61 |
O1'—C2'—N3' | 114.59 (16) | C9'—C4'—H4' | 121.61 |
C2—C3—C2' | 126.97 (17) | C4'—C5'—H5' | 118.99 |
C5'—C4'—C9' | 116.8 (2) | C6'—C5'—H5' | 119.00 |
C4'—C5'—C6' | 122.0 (2) | C5'—C6'—H6' | 118.90 |
C5'—C6'—C7' | 122.1 (2) | C7'—C6'—H6' | 118.96 |
C6'—C7'—C8' | 115.08 (19) | C6'—C7'—H7' | 122.46 |
O1'—C8'—C9' | 107.70 (16) | C8'—C7'—H7' | 122.47 |
C7'—C8'—C9' | 124.01 (18) | ||
C8'—O1'—C2'—N3' | 0.4 (2) | N3'—C2'—C3—C2 | 178.51 (19) |
C2'—O1'—C8'—C7' | 178.88 (19) | C5'—C4'—C9'—N3' | 178.7 (2) |
C2'—O1'—C8'—C9' | −0.49 (19) | C5'—C4'—C9'—C8' | −0.3 (3) |
C8'—O1'—C2'—C3 | −178.08 (16) | C9'—C4'—C5'—C6' | 0.0 (3) |
C9'—N3'—C2'—O1' | −0.1 (2) | C4'—C5'—C6'—C7' | 0.4 (4) |
C2'—N3'—C9'—C4' | −179.3 (2) | C5'—C6'—C7'—C8' | −0.4 (3) |
C2'—N3'—C9'—C8' | −0.17 (19) | C6'—C7'—C8'—C9' | 0.1 (3) |
C9'—N3'—C2'—C3 | 178.23 (17) | C6'—C7'—C8'—O1' | −179.18 (18) |
O1A—C1—C2—C3 | −79.5 (3) | O1'—C8'—C9'—C4' | 179.66 (16) |
O1B—C1—C2—C3 | 103.7 (3) | C7'—C8'—C9'—N3' | −178.98 (17) |
C1—C2—C3—C2' | 0.4 (3) | C7'—C8'—C9'—C4' | 0.3 (3) |
O1'—C2'—C3—C2 | −3.2 (3) | O1'—C8'—C9'—N3' | 0.4 (2) |
Symmetry codes: (i) −x+1/2, −y+1/2, −z; (ii) x+1/2, y+1/2, z; (iii) −x+1/2, y+1/2, −z+1/2; (iv) −x+1/2, −y+3/2, −z; (v) −x+1, y, −z+1/2; (vi) −x, −y+1, −z; (vii) x−1/2, y−1/2, z; (viii) −x+1/2, y−1/2, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1A—H1A···N3′ii | 0.82 | 1.90 | 2.715 (2) | 172 |
C3—H3···O1Bviii | 0.93 | 2.43 | 3.310 (3) | 159 |
Symmetry codes: (ii) x+1/2, y+1/2, z; (viii) −x+1/2, y−1/2, −z+1/2. |
Experimental details
(I-E) | (I-Z) | |
Crystal data | ||
Chemical formula | C10H7NO3 | C10H7NO3 |
Mr | 189.17 | 189.17 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, C2/c |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 5.882 (1), 19.694 (1), 7.4910 (1) | 9.8191 (19), 9.905 (2), 18.320 (4) |
β (°) | 91.715 (10) | 94.037 (4) |
V (Å3) | 867.37 (15) | 1777.4 (6) |
Z | 4 | 8 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.11 | 0.11 |
Crystal size (mm) | 0.50 × 0.50 × 0.40 | 0.36 × 0.21 × 0.19 |
Data collection | ||
Diffractometer | Enraf–Nonius CAD-4 diffractometer | Bruker SMART area-detector diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2082, 2082, 1554 | 9736, 2013, 1559 |
Rint | 0.011 | 0.035 |
(sin θ/λ)max (Å−1) | 0.660 | 0.650 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.124, 1.15 | 0.053, 0.127, 1.05 |
No. of reflections | 2082 | 2013 |
No. of parameters | 128 | 128 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.19, −0.18 | 0.23, −0.18 |
Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1992), SMART (Bruker, 2000), CAD-4 EXPRESS, SMART, JANA98 (Vaclav, 1998), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), WinGX (Farrugia, 1999), SHELXTL (Bruker, 2000), SHELXL97 and WinGX2003 (Farrugia, 1999).
O1'—C2' | 1.3588 (17) | O1B—C1 | 1.1978 (19) |
O1'—C8' | 1.3800 (16) | N3'—C2' | 1.2987 (17) |
O1A—C1 | 1.324 (2) | N3'—C9' | 1.3962 (18) |
C2'—O1'—C8' | 104.23 (10) | N3'—C2'—C3 | 127.00 (12) |
C2'—N3'—C9' | 104.76 (11) | O1'—C2'—N3' | 114.92 (12) |
O1A—C1—C2 | 111.12 (12) | O1'—C8'—C9' | 107.77 (12) |
O1B—C1—C2 | 124.61 (16) | N3'—C9'—C8' | 108.32 (11) |
O1A—C1—O1B | 124.25 (14) | N3'—C9'—C4' | 131.53 (12) |
O1'—C2'—C3 | 118.08 (11) | ||
O1'—C2'—C3—C2 | 2.5 (2) | N3'—C2'—C3—C2 | −178.33 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1A—H1A···N3'i | 0.82 | 1.89 | 2.6995 (16) | 167 |
C2—H2···O1' | 0.93 | 2.50 | 2.8196 (18) | 100 |
C5'—H5'···O1Bii | 0.93 | 2.46 | 3.372 (2) | 165 |
Symmetry codes: (i) x−1, −y+1/2, z−1/2; (ii) −x+1, y−1/2, −z+1/2. |
O1'—C2' | 1.359 (2) | O1B—C1 | 1.200 (2) |
O1'—C8' | 1.382 (2) | N3'—C2' | 1.298 (2) |
O1A—C1 | 1.305 (2) | N3'—C9' | 1.399 (3) |
C2'—O1'—C8' | 104.51 (13) | O1'—C2'—C3 | 119.65 (15) |
C2'—N3'—C9' | 105.13 (15) | N3'—C2'—C3 | 125.74 (17) |
O1A—C1—C2 | 113.76 (16) | O1'—C2'—N3' | 114.59 (16) |
O1B—C1—C2 | 121.59 (18) | O1'—C8'—C7' | 128.29 (17) |
O1A—C1—O1B | 124.57 (18) | N3'—C9'—C4' | 131.94 (18) |
O1A—C1—C2—C3 | −79.5 (3) | O1'—C2'—C3—C2 | −3.2 (3) |
O1B—C1—C2—C3 | 103.7 (3) | N3'—C2'—C3—C2 | 178.51 (19) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1A—H1A···N3'i | 0.82 | 1.90 | 2.715 (2) | 172 |
C3—H3···O1Bii | 0.93 | 2.43 | 3.310 (3) | 159 |
Symmetry codes: (i) x+1/2, y+1/2, z; (ii) −x+1/2, y−1/2, −z+1/2. |
γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system (CNS). It operates through three different classes of receptors, consisting of the ionotropic GABAA and GABAC receptors, and the G-protein coupled receptor GABAB (Chebib & Johnston, 2000). Hypoactivity of the GABA neuronal function has been associated with neurological disorders such as epilepsy, Huntington's chorea, anxiety, sleep disorders and pain. AUTHOR: are you saying that pain is a neurological disorder? Can you be more specific? In contrast, GABA mediated hyperactivity has been suggested to be an important component of schizophrenic symptoms (Frølund et al., 2002). In order to pharmacologically characterize these receptors, recent studies on the synthesis and characterization of several GABA agonists (Chambers et al., 2003; Frølund et al., 1995) and antagonists (Frølund et al., 2002) have been undertaken. GABA is a conformationally flexible molecule, capable of adopting receptor subtype-specific conformations; in this context, we report the results of structural analyses of the E and Z geometric isomers of 3-(benzoxazolyl)-2-propenoic acid [(I—E) and (I—Z), respectively], which are analogues of GABA.
A one-pot synthesis was carried out by mixing equimolar quantities of maleic anhydride with o-aminophenol in THF. Careful regulation of the temperature to 323 K, using Ac2O as catalyst, yielded isomer (I—Z); isomer (I—E) was obtained when the temperature was raised to 343 K and an excess of Ac2O was used. It appears that isomer (I—Z) is the kinetic product and isomer (I—E) is the thermodynamic product, since the former is observed by thin-layer chromatography in the early stages of the reaction. The molecular structures of isomers (I—E) and (I—Z) are shown in Figs. 1 and 2, respectively, while selected geometric parameters are given in Table 1 and Table 3, respectively. The bond lengths and angles are very similar in the two isomers, as is the anti disposition of the double bond and the imine groups. However, the carboxy and benzoxazole groups are on opposite sides in (I—E) and on the same side in (I—Z).
AUTHOR: At some point, do you want to mention briefly the intramolecular C—H···O contact? The carboxy group in (I—E) is coplanar with the double bond, whereas in (I—Z) these groups are almost orthogonal [O1B—C1—C2—C3 = −4.1 (2) and 103.7 (3)°, respectively], in agreement with the conformation reported for other Z-propenoic acids (Stomberg et al., 1995). This conformational difference between the isomers determines the observed crystal packing structure (see below). Isomer (I—E) forms supramolecular sheets in the (102) plane through both strong (Steiner, 2002), and weak (Desiraju, 1996) hydrogen-bonding interactions. The hydrogen-bonding geometry for isomer (I—E) is listed in Table 2. The carboxylic acid donor and pyridine-like N-atom acceptor form a strong O1A—H1A···N3'i interaction [symmetry code: (i) x − 1, 1/2 − y, −1/2 + z], which is complemented by the weak C5'—H5'···O1Bii interaction [symmetry code: (ii) 1 − x, y − 1/2, 1/2 − z] between an aromatic H-atom donor and a carbonyl O-atom acceptor (Fig. 3).
Centrosymmetric sheets pack via π–π stacking interactions (Hunter et al., 1991; Singh & Thornton, 1990) between oxazole and benzenoid rings along the c axis. The mean intercentroid and interplanar distances [3.7070 (10) {or 3.707 (1)?} and 3.435 (s.u.?) Å, respectively] at the (1 − x, −y, −z) symmetry position, (iii), indicate a face-to-face π–π stacking arrangement, whereas the distances [4.4487 (11) and 3.38 (2) Å] at the (1 − x, −y, 1 − z) symmetry position, (iv), indicate a parallel displaced π–π stacking arrangement. The former arrangement is overwhelmingly preferred in the stacking of electron-rich and electron deficient aromatic rings, such as benzene and hexafluorobenzene, whose 1:1 complex has mean intercentroid and interplanar distances of 3.7 and 3.4 Å, respectively (Williams, 1993). The electron-deficient carbonyl C atom is located 3.42 (2) Å from the electron-rich double bond of the neighbouring molecule [symmetry code: (v) x, 1/2 − y, −1/2 + z], forming an angle of 68 (1)° with it (Fig. 3). This distance is as short as the sum of the van der Waals radii of two C atoms (3.4 Å; Hunter et al., 1991), and the carbonyl group is parallel but slightly slipped [displaced?] relative to the double bond. Therefore, this interaction can be considered as a paralled displaced olefin-type π–π stacking interaction (Kim et al., 2000), which should be an important contributor to the slippage of the hydrogen-bonded supramolecular sheets of isomer (I—E).
Molecules of (I—Z) are linked by a strong hydrogen-bonding interaction [O1A—H1A···N3'i; symmetry code: (i) 1/2 + x, 1/2 + y, z], between the carboxylic acid donor and pyridine-like N-atom acceptor, and a weak interaction [C3—H3···O1Bii; symmetry code: (ii) 1/2 − x, y − 1/2, 1/2 − z], involving a vinyl H-atom donor and the carbonyl O-atom acceptor (Fig. 4). As a consequence, a twisted eight-membered chain is formed, whose topological motif is described by the C(8)[C(7) C(5)] graph-set descriptor (Bernstein et al., 1995). This interaction is allowed because of the almost perpendicular conformation between the carboxy and the double-bond groups. The hydrogen-bonding geometry for isomer (I—Z) is listed in Table 4.
Centrosymmetric molecules of isomer (I—Z) also form π–π stacks, two almost perpendicular sets of columns developing in the [230] and [230] directions (Fig. 4). The mean intercentroid and interplanar distances between the oxazole [3.4727 (13) and 3.378 (s.u.?)Å; symmetry code: (iii) −x, 1 − y, −z] and benzenoid rings [3.5631 (14) and 3.310 (s.u.?) Å; symmetry code: (iv) 1/2 − x, 1/2 − y, −z] are also in the range expected for a face-to-face geometry (Hunter et al., 1991; Singh & Thornton, 1990), with less slippage than observed for isomer (I—E).