Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801004445/cv6009sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801004445/cv6009Isup2.hkl |
CCDC reference: 162818
Key indicators
- Single-crystal X-ray study
- T = 296 K
- Mean (C-C) = 0.005 Å
- R factor = 0.054
- wR factor = 0.158
- Data-to-parameter ratio = 18.4
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Alert Level C:
PLAT_369 Alert C Long C(sp2)-C(sp2) Bond C(1) - C(2) = 1.53 Ang.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check
To a pyridine solution (2 ml) of 4-isopropyltropolone (164 mg, 1.0 mmol) was added drop by drop an aqueous solution of a diazotized 4-ethoxycarbonylaniline (248 mg, 1.5 mmol) at 273 to 278 K with stirring for 2 h. After the solution was diluted with water (10 ml), the precipitate was filtrered and dried. An ethanol solution of the precipitate was refluxed for 4 h and cooled to yield the title compound (I) (142 mg, 42%) by filtration (Mori et al., 1989). The single crystals of (I) were obtained by recrystallization from chloroform.
All H atoms were located at ideal positions and restrained with Uiso held fixed to 1.2Ueq of the parent atoms.
Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Xtal_GX (Hall & du Boulay, 1995); software used to prepare material for publication: SHELXL97.
C19H18N2O4 | Dx = 1.305 Mg m−3 |
Mr = 338.35 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pbca | Cell parameters from 16 reflections |
a = 19.028 (3) Å | θ = 9.2–17.9° |
b = 19.166 (3) Å | µ = 0.09 mm−1 |
c = 9.4466 (5) Å | T = 296 K |
V = 3445.1 (7) Å3 | Prism, red |
Z = 8 | 0.33 × 0.27 × 0.13 mm |
F(000) = 1424 |
Enraf-Nonius CAD-4 diffractometer | 1280 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.000 |
Graphite monochromator | θmax = 28.0°, θmin = 2.6° |
ω–2θ scans | h = 0→25 |
Absorption correction: ψ scan (North et al., 1968) | k = −25→0 |
Tmin = 0.969, Tmax = 0.998 | l = 0→12 |
4149 measured reflections | 3 standard reflections every 120 min |
4149 independent reflections | intensity decay: 0.5% |
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)] = 0.054 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.158 | H-atom parameters constrained |
S = 0.89 | w = 1/[σ2(Fo2) + (0.0539P)2] where P = (Fo2 + 2Fc2)/3 |
4149 reflections | (Δ/σ)max = 0.001 |
226 parameters | Δρmax = 0.20 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
C19H18N2O4 | V = 3445.1 (7) Å3 |
Mr = 338.35 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 19.028 (3) Å | µ = 0.09 mm−1 |
b = 19.166 (3) Å | T = 296 K |
c = 9.4466 (5) Å | 0.33 × 0.27 × 0.13 mm |
Enraf-Nonius CAD-4 diffractometer | 1280 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.000 |
Tmin = 0.969, Tmax = 0.998 | 3 standard reflections every 120 min |
4149 measured reflections | intensity decay: 0.5% |
4149 independent reflections |
R[F2 > 2σ(F2)] = 0.054 | 0 restraints |
wR(F2) = 0.158 | H-atom parameters constrained |
S = 0.89 | Δρmax = 0.20 e Å−3 |
4149 reflections | Δρmin = −0.24 e Å−3 |
226 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. |
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 | ||
N1 | 0.88831 (14) | 0.14229 (13) | 0.0112 (3) | 0.0469 (7) | |
N2 | 0.86161 (13) | 0.08041 (12) | 0.0463 (3) | 0.0435 (7) | |
O1 | 0.75989 (15) | 0.38435 (12) | 0.2298 (3) | 0.0966 (10) | |
O2 | 0.72097 (12) | 0.28665 (12) | 0.4086 (3) | 0.0699 (8) | |
O3 | 1.01239 (14) | −0.15229 (13) | −0.3384 (3) | 0.0802 (9) | |
O4 | 0.94270 (12) | −0.21630 (13) | −0.1981 (3) | 0.0688 (8) | |
C1 | 0.7870 (2) | 0.32710 (17) | 0.2157 (4) | 0.0602 (11) | |
C2 | 0.75567 (18) | 0.26834 (17) | 0.3058 (4) | 0.0526 (9) | |
C3 | 0.76344 (17) | 0.19528 (16) | 0.2746 (4) | 0.0517 (9) | |
H3 | 0.7350 | 0.1657 | 0.3275 | 0.062* | |
C4 | 0.80545 (16) | 0.16337 (15) | 0.1810 (3) | 0.0411 (8) | |
C5 | 0.85689 (16) | 0.19151 (15) | 0.0873 (3) | 0.0426 (8) | |
C6 | 0.87661 (17) | 0.26265 (15) | 0.0660 (4) | 0.0534 (9) | |
H6 | 0.9144 | 0.2702 | 0.0056 | 0.064* | |
C7 | 0.8474 (2) | 0.31988 (16) | 0.1223 (4) | 0.0598 (10) | |
H7 | 0.8691 | 0.3616 | 0.0977 | 0.072* | |
C8 | 0.80673 (16) | 0.08491 (14) | 0.1579 (3) | 0.0417 (8) | |
C9 | 0.73500 (16) | 0.05919 (15) | 0.1045 (4) | 0.0533 (9) | |
H9A | 0.7367 | 0.0096 | 0.0904 | 0.080* | |
H9B | 0.7240 | 0.0818 | 0.0166 | 0.080* | |
H9C | 0.6995 | 0.0701 | 0.1733 | 0.080* | |
C10 | 0.83016 (18) | 0.04850 (15) | 0.2944 (3) | 0.0556 (10) | |
H10A | 0.8311 | −0.0010 | 0.2795 | 0.083* | |
H10B | 0.7977 | 0.0593 | 0.3691 | 0.083* | |
H10C | 0.8763 | 0.0644 | 0.3200 | 0.083* | |
C11 | 0.88638 (16) | 0.02091 (15) | −0.0251 (3) | 0.0401 (8) | |
C12 | 0.86496 (17) | −0.04586 (15) | 0.0119 (3) | 0.0470 (9) | |
H12 | 0.8323 | −0.0520 | 0.0841 | 0.056* | |
C13 | 0.89192 (17) | −0.10316 (16) | −0.0580 (3) | 0.0472 (8) | |
H13 | 0.8776 | −0.1476 | −0.0312 | 0.057* | |
C14 | 0.93974 (16) | −0.09575 (17) | −0.1668 (4) | 0.0483 (8) | |
C15 | 0.95942 (17) | −0.02876 (18) | −0.2044 (4) | 0.0576 (10) | |
H15 | 0.9912 | −0.0227 | −0.2781 | 0.069* | |
C16 | 0.93345 (16) | 0.02937 (17) | −0.1359 (4) | 0.0532 (9) | |
H16 | 0.9474 | 0.0738 | −0.1638 | 0.064* | |
C17 | 0.96954 (19) | −0.1561 (2) | −0.2448 (4) | 0.0588 (10) | |
C18 | 0.9630 (2) | −0.27980 (19) | −0.2713 (4) | 0.0785 (13) | |
H18A | 1.0137 | −0.2814 | −0.2820 | 0.094* | |
H18B | 0.9420 | −0.2808 | −0.3648 | 0.094* | |
C19 | 0.93878 (19) | −0.34069 (18) | −0.1878 (4) | 0.0796 (13) | |
H19A | 0.9520 | −0.3829 | −0.2355 | 0.119* | |
H19B | 0.8886 | −0.3390 | −0.1782 | 0.119* | |
H19C | 0.9601 | −0.3396 | −0.0957 | 0.119* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0529 (18) | 0.0388 (15) | 0.0489 (17) | −0.0065 (14) | 0.0043 (15) | 0.0014 (14) |
N2 | 0.0482 (16) | 0.0353 (15) | 0.0472 (18) | −0.0002 (13) | 0.0113 (14) | 0.0002 (14) |
O1 | 0.109 (2) | 0.0492 (16) | 0.131 (3) | 0.0277 (15) | −0.001 (2) | 0.0067 (17) |
O2 | 0.0709 (17) | 0.0655 (16) | 0.0734 (18) | 0.0176 (13) | −0.0015 (15) | −0.0229 (15) |
O3 | 0.0790 (19) | 0.0847 (19) | 0.077 (2) | 0.0077 (15) | 0.0273 (17) | −0.0220 (16) |
O4 | 0.0736 (17) | 0.0551 (16) | 0.0776 (19) | 0.0036 (13) | 0.0131 (15) | −0.0263 (15) |
C1 | 0.072 (3) | 0.038 (2) | 0.070 (3) | 0.0117 (19) | −0.020 (2) | −0.005 (2) |
C2 | 0.050 (2) | 0.051 (2) | 0.057 (2) | 0.0113 (16) | −0.014 (2) | −0.015 (2) |
C3 | 0.051 (2) | 0.047 (2) | 0.058 (2) | −0.0047 (17) | 0.006 (2) | −0.0025 (18) |
C4 | 0.0421 (18) | 0.0397 (18) | 0.042 (2) | 0.0014 (16) | −0.0009 (17) | 0.0016 (17) |
C5 | 0.042 (2) | 0.0393 (19) | 0.046 (2) | −0.0035 (16) | −0.0019 (18) | 0.0035 (17) |
C6 | 0.061 (2) | 0.043 (2) | 0.057 (2) | −0.0079 (17) | −0.0037 (19) | 0.0033 (18) |
C7 | 0.074 (3) | 0.040 (2) | 0.066 (3) | −0.007 (2) | −0.012 (2) | 0.0039 (19) |
C8 | 0.0471 (19) | 0.0381 (18) | 0.040 (2) | 0.0010 (16) | 0.0089 (17) | 0.0014 (16) |
C9 | 0.050 (2) | 0.0447 (19) | 0.065 (2) | −0.0102 (16) | 0.0072 (19) | −0.0059 (18) |
C10 | 0.073 (2) | 0.049 (2) | 0.046 (2) | −0.0006 (18) | 0.0039 (19) | 0.0044 (18) |
C11 | 0.041 (2) | 0.0419 (19) | 0.037 (2) | 0.0050 (16) | 0.0009 (16) | −0.0014 (16) |
C12 | 0.050 (2) | 0.047 (2) | 0.044 (2) | 0.0015 (17) | 0.0059 (17) | 0.0010 (17) |
C13 | 0.054 (2) | 0.0411 (19) | 0.046 (2) | 0.0034 (16) | −0.0055 (19) | −0.0017 (17) |
C14 | 0.046 (2) | 0.052 (2) | 0.047 (2) | 0.0071 (17) | 0.0009 (19) | −0.0089 (19) |
C15 | 0.052 (2) | 0.066 (2) | 0.055 (2) | −0.0014 (18) | 0.014 (2) | −0.008 (2) |
C16 | 0.056 (2) | 0.049 (2) | 0.054 (2) | −0.0008 (18) | 0.013 (2) | −0.0028 (18) |
C17 | 0.050 (2) | 0.066 (3) | 0.061 (3) | 0.003 (2) | −0.003 (2) | −0.020 (2) |
C18 | 0.086 (3) | 0.064 (3) | 0.085 (3) | 0.012 (2) | −0.003 (3) | −0.043 (3) |
C19 | 0.070 (3) | 0.058 (2) | 0.110 (4) | 0.009 (2) | 0.009 (3) | −0.026 (3) |
N1—C5 | 1.328 (3) | C9—H9B | 0.9600 |
N1—N2 | 1.332 (3) | C9—H9C | 0.9600 |
N2—C8 | 1.486 (4) | C10—H10A | 0.9600 |
N2—C11 | 1.406 (3) | C10—H10B | 0.9600 |
O1—C1 | 1.220 (4) | C10—H10C | 0.9600 |
O2—C2 | 1.225 (4) | C11—C16 | 1.387 (4) |
O3—C17 | 1.205 (4) | C11—C12 | 1.388 (4) |
O4—C17 | 1.337 (4) | C12—C13 | 1.380 (4) |
O4—C18 | 1.452 (3) | C12—H12 | 0.9300 |
C1—C2 | 1.533 (5) | C13—C14 | 1.380 (4) |
C1—C7 | 1.455 (5) | C13—H13 | 0.9300 |
C2—C3 | 1.439 (4) | C14—C15 | 1.384 (4) |
C3—C4 | 1.340 (4) | C14—C17 | 1.484 (5) |
C3—H3 | 0.9300 | C15—C16 | 1.380 (4) |
C4—C5 | 1.426 (4) | C15—H15 | 0.9300 |
C4—C8 | 1.520 (4) | C16—H16 | 0.9300 |
C5—C6 | 1.428 (4) | C18—C19 | 1.482 (5) |
C6—C7 | 1.339 (4) | C18—H18A | 0.9700 |
C6—H6 | 0.9300 | C18—H18B | 0.9700 |
C7—H7 | 0.9300 | C19—H19A | 0.9600 |
C8—C9 | 1.536 (4) | C19—H19B | 0.9600 |
C8—C10 | 1.533 (4) | C19—H19C | 0.9600 |
C9—H9A | 0.9600 | ||
C5—N1—N2 | 109.0 (2) | C8—C10—H10B | 109.5 |
N1—N2—C11 | 118.4 (2) | H10A—C10—H10B | 109.5 |
N1—N2—C8 | 113.1 (2) | C8—C10—H10C | 109.5 |
C11—N2—C8 | 128.5 (2) | H10A—C10—H10C | 109.5 |
C17—O4—C18 | 117.7 (3) | H10B—C10—H10C | 109.5 |
O1—C1—C7 | 119.1 (4) | C16—C11—C12 | 119.2 (3) |
O1—C1—C2 | 115.8 (4) | C16—C11—N2 | 118.9 (3) |
C7—C1—C2 | 125.1 (3) | C12—C11—N2 | 121.9 (3) |
O2—C2—C3 | 119.8 (3) | C13—C12—C11 | 120.3 (3) |
O2—C2—C1 | 116.1 (3) | C13—C12—H12 | 119.9 |
C3—C2—C1 | 124.2 (3) | C11—C12—H12 | 119.9 |
C4—C3—C2 | 129.9 (3) | C12—C13—C14 | 121.3 (3) |
C4—C3—H3 | 115.1 | C12—C13—H13 | 119.3 |
C2—C3—H3 | 115.1 | C14—C13—H13 | 119.3 |
C3—C4—C5 | 130.3 (3) | C13—C14—C15 | 117.7 (3) |
C3—C4—C8 | 123.8 (3) | C13—C14—C17 | 122.8 (3) |
C5—C4—C8 | 105.9 (3) | C15—C14—C17 | 119.5 (3) |
N1—C5—C4 | 112.1 (3) | C16—C15—C14 | 122.2 (3) |
N1—C5—C6 | 118.9 (3) | C16—C15—H15 | 118.9 |
C4—C5—C6 | 129.0 (3) | C14—C15—H15 | 118.9 |
C7—C6—C5 | 128.1 (3) | C15—C16—C11 | 119.4 (3) |
C7—C6—H6 | 116.0 | C15—C16—H16 | 120.3 |
C5—C6—H6 | 116.0 | C11—C16—H16 | 120.3 |
C6—C7—C1 | 130.2 (3) | O3—C17—O4 | 123.6 (3) |
C6—C7—H7 | 114.9 | O3—C17—C14 | 125.1 (4) |
C1—C7—H7 | 114.9 | O4—C17—C14 | 111.3 (3) |
N2—C8—C4 | 99.8 (2) | O4—C18—C19 | 108.9 (3) |
N2—C8—C10 | 111.5 (2) | O4—C18—H18A | 109.9 |
C4—C8—C10 | 109.5 (3) | C19—C18—H18A | 109.9 |
N2—C8—C9 | 111.9 (3) | O4—C18—H18B | 109.9 |
C4—C8—C9 | 110.5 (2) | C19—C18—H18B | 109.9 |
C10—C8—C9 | 112.8 (3) | H18A—C18—H18B | 108.3 |
C8—C9—H9A | 109.5 | C18—C19—H19A | 109.5 |
C8—C9—H9B | 109.5 | C18—C19—H19B | 109.5 |
H9A—C9—H9B | 109.5 | H19A—C19—H19B | 109.5 |
C8—C9—H9C | 109.5 | C18—C19—H19C | 109.5 |
H9A—C9—H9C | 109.5 | H19A—C19—H19C | 109.5 |
H9B—C9—H9C | 109.5 | H19B—C19—H19C | 109.5 |
C8—C10—H10A | 109.5 | ||
C5—N1—N2—C11 | 178.3 (3) | C3—C4—C8—N2 | −179.7 (3) |
C5—N1—N2—C8 | −0.6 (3) | C5—C4—C8—N2 | −0.7 (3) |
O1—C1—C2—O2 | −19.3 (5) | C3—C4—C8—C10 | −62.6 (4) |
C7—C1—C2—O2 | 157.8 (3) | C5—C4—C8—C10 | 116.4 (3) |
O1—C1—C2—C3 | 159.3 (3) | C3—C4—C8—C9 | 62.3 (4) |
C7—C1—C2—C3 | −23.6 (5) | C5—C4—C8—C9 | −118.7 (3) |
O2—C2—C3—C4 | −170.4 (3) | C8—N2—C11—C16 | 173.8 (3) |
C1—C2—C3—C4 | 11.1 (6) | N1—N2—C11—C12 | 175.4 (3) |
C2—C3—C4—C5 | 2.5 (6) | N1—N2—C11—C16 | −4.8 (4) |
C2—C3—C4—C8 | −178.7 (3) | C8—N2—C11—C12 | −6.0 (5) |
N2—N1—C5—C4 | 0.0 (4) | C16—C11—C12—C13 | 2.0 (5) |
N2—N1—C5—C6 | −179.2 (3) | N2—C11—C12—C13 | −178.2 (3) |
C3—C4—C5—N1 | 179.4 (3) | C11—C12—C13—C14 | −0.9 (5) |
C8—C4—C5—N1 | 0.4 (3) | C12—C13—C14—C15 | −0.5 (5) |
C3—C4—C5—C6 | −1.4 (6) | C12—C13—C14—C17 | −179.7 (3) |
C8—C4—C5—C6 | 179.6 (3) | C13—C14—C15—C16 | 0.7 (5) |
N1—C5—C6—C7 | 173.7 (3) | C17—C14—C15—C16 | 179.9 (3) |
C4—C5—C6—C7 | −5.4 (6) | C14—C15—C16—C11 | 0.4 (5) |
C5—C6—C7—C1 | −2.2 (6) | C12—C11—C16—C15 | −1.7 (5) |
O1—C1—C7—C6 | −164.0 (4) | N2—C11—C16—C15 | 178.4 (3) |
C2—C1—C7—C6 | 19.0 (6) | C18—O4—C17—O3 | −4.3 (5) |
N1—N2—C8—C4 | 0.8 (3) | C18—O4—C17—C14 | 175.6 (3) |
C11—N2—C8—C4 | −177.9 (3) | C13—C14—C17—O3 | −178.4 (3) |
N1—N2—C8—C9 | 117.7 (3) | C15—C14—C17—O3 | 2.4 (5) |
N1—N2—C8—C10 | −114.9 (3) | C13—C14—C17—O4 | 1.6 (5) |
C11—N2—C8—C10 | 66.4 (4) | C15—C14—C17—O4 | −177.6 (3) |
C11—N2—C8—C9 | −61.0 (4) | C17—O4—C18—C19 | 169.5 (3) |
Experimental details
Crystal data | |
Chemical formula | C19H18N2O4 |
Mr | 338.35 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 296 |
a, b, c (Å) | 19.028 (3), 19.166 (3), 9.4466 (5) |
V (Å3) | 3445.1 (7) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.33 × 0.27 × 0.13 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.969, 0.998 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4149, 4149, 1280 |
Rint | 0.000 |
(sin θ/λ)max (Å−1) | 0.660 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.158, 0.89 |
No. of reflections | 4149 |
No. of parameters | 226 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.24 |
Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, MolEN (Fair, 1990), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), Xtal_GX (Hall & du Boulay, 1995), SHELXL97.
N1—C5 | 1.328 (3) | C2—C3 | 1.439 (4) |
N1—N2 | 1.332 (3) | C3—C4 | 1.340 (4) |
N2—C8 | 1.486 (4) | C4—C5 | 1.426 (4) |
N2—C11 | 1.406 (3) | C4—C8 | 1.520 (4) |
O1—C1 | 1.220 (4) | C5—C6 | 1.428 (4) |
O2—C2 | 1.225 (4) | C6—C7 | 1.339 (4) |
C1—C2 | 1.533 (5) | C8—C9 | 1.536 (4) |
C1—C7 | 1.455 (5) | C8—C10 | 1.533 (4) |
O1—C1—C2—O2 | −19.3 (5) | C18—O4—C17—C14 | 175.6 (3) |
N1—N2—C8—C9 | 117.7 (3) | C13—C14—C17—O3 | −178.4 (3) |
N1—N2—C8—C10 | −114.9 (3) | C13—C14—C17—O4 | 1.6 (5) |
N1—N2—C11—C12 | 175.4 (3) | C17—O4—C18—C19 | 169.5 (3) |
N1—N2—C11—C16 | −4.8 (4) |
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Hinopurpurins (2-aryl-2,3-dihydro-3,3-dimethyl-5,6-cycloheptapyrazoledione) are known to be stable dyes (Mori et al., 1989). The title compound, 4-ethoxycarbonylphenylhinopurpurin, (I), showed a remarkably large negative halochromism; 484 nm in ethyl acetate, 517, 566, and 600 (sh) nm in trifluoroacetic acid, and 455 nm in concentrated sulfuric acid. However, the crystal structures of hinopurpurins have not ever been elucidated. We now report the structure of (I) to elucidate the properties as a dye.
The C—C and C═C bond lengths of the seven-membered ring show apparent bond alternation. The C1═O1 [1.220 (4) Å] and C2═O2 [1.225 (4) Å] bond lengths are similar to that (1.259 Å) of tropone (Barrow et al., 1973). The N1—N2 [1.332 (3) Å] and N1═C5 [1.328 (3) Å] bond lengths are close to those [1.343 Å for N—N and 1.322 Å for N═C] of pyrazole (la Cour & Rasmussen, 1973).
The deviations of each atom from the least-squares plane of the seven-membered ring are -0.134 (4) Å for C1, 0.097 (4) Å for C2, 0.025 (4) Å for C3, -0.041 (4) Å for C4, -0.014 (4) Å for C5, 0.064 (4) Å for C6, and 0.032 (4) Å for C7. The diketone structure (A) (least-squares plane defined by C1, C2, O1 and O2) intersects the seven-membered ring (B) (defined by atoms C1–C7) at an angle of 15.5 (1)°. The dihydropyrazole ring (C) (defined by atoms N1, N2, C4, C5 and C8) is almost coplanar with the seven-membered ring (B), the benzene ring (D), the carboxy group (E) (defined by atoms C17, O3 and O4). The dihedral angles between planes B and C, between C and D, and between C and E are 4.1 (1), 5.3 (1) and 4.3 (4)°, respectively.