Acta Cryst. (2009). E65, o238 [ doi:10.1107/S1600536808043912 ]
The asymmetric unit of the title compound, C16H20N4, contains two half-molecules, which are completed by crystallographic inversion symmetry. The pyridazine rings are conjugated and the cyclohexane rings adopt envelope conformations.
The title compound was prepared by the reaction of 3,4,6,7-tetrahydro- 3,3,6,6,9-pentamethyl-2H-xanthene-1,8(5H,9H)-dione (2 mmol) and hydrazine hydrate (8 mmol, 80%) in ethanol (8 ml), stirring at 353 K (yield; 88%, m.p. 562-563 K). Crystals suitable for X-ray analysis were obtained from an ethanol solution by slow evaporation.
H atoms were positioned geometrically, with C-H = 0.97 and 0.96 Å for methylene and methyl H and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and x = 1.2 for methylene H atoms.
Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./hk2606fig1thm.gif)
| Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry code (A): -x, -y, -z]. |
| C16H20N4 | F(000) = 576 |
| Mr = 268.36 | Dx = 1.243 Mg m−3 |
| Monoclinic, P21/n | Melting point = 562–563 K |
| Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71073 Å |
| a = 12.819 (4) Å | Cell parameters from 1230 reflections |
| b = 8.441 (3) Å | θ = 2.3–23.2° |
| c = 13.310 (4) Å | µ = 0.08 mm−1 |
| β = 95.462 (5)° | T = 298 K |
| V = 1433.7 (8) Å3 | Block, pale yellow |
| Z = 4 | 0.33 × 0.28 × 0.21 mm |
| Bruker SMART CCD area-detector diffractometer | 2518 independent reflections |
| Radiation source: fine-focus sealed tube | 1416 reflections with I > 2σ(I) |
| graphite | Rint = 0.048 |
| φ and ω scans | θmax = 25.0°, θmin = 2.1° |
| Absorption correction: multi-scan (SADABS; Bruker, 1998) | h = −15→15 |
| Tmin = 0.975, Tmax = 0.984 | k = −9→10 |
| 7218 measured reflections | l = −15→14 |
| 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)] = 0.052 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.179 | H-atom parameters constrained |
| S = 1.04 | w = 1/[σ2(Fo2) + 0.3048P] where P = (Fo2 + 2Fc2)/3 |
| 2518 reflections | (Δ/σ)max < 0.001 |
| 185 parameters | Δρmax = 0.18 e Å−3 |
| 0 restraints | Δρmin = −0.20 e Å−3 |
| C16H20N4 | V = 1433.7 (8) Å3 |
| Mr = 268.36 | Z = 4 |
| Monoclinic, P21/n | Mo Kα radiation |
| a = 12.819 (4) Å | µ = 0.08 mm−1 |
| b = 8.441 (3) Å | T = 298 K |
| c = 13.310 (4) Å | 0.33 × 0.28 × 0.21 mm |
| β = 95.462 (5)° |
| Bruker SMART CCD area-detector diffractometer | 2518 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 1998) | 1416 reflections with I > 2σ(I) |
| Tmin = 0.975, Tmax = 0.984 | Rint = 0.048 |
| 7218 measured reflections | θmax = 25.0° |
| R[F2 > 2σ(F2)] = 0.052 | H-atom parameters constrained |
| wR(F2) = 0.179 | Δρmax = 0.18 e Å−3 |
| S = 1.04 | Δρmin = −0.20 e Å−3 |
| 2518 reflections | Absolute structure: ? |
| 185 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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 | 1.11488 (18) | 0.2369 (3) | 0.00759 (19) | 0.0510 (7) | |
| N2 | 1.16426 (18) | 0.1239 (3) | −0.04672 (19) | 0.0513 (7) | |
| N3 | 0.50653 (19) | 0.2577 (3) | −0.08920 (17) | 0.0469 (6) | |
| N4 | 0.56253 (19) | 0.1517 (3) | −0.14224 (17) | 0.0470 (6) | |
| C1 | 1.0250 (2) | 0.2044 (3) | 0.04438 (19) | 0.0394 (7) | |
| C2 | 0.97626 (18) | 0.0553 (3) | 0.02796 (18) | 0.0350 (7) | |
| C3 | 1.1205 (2) | −0.0146 (3) | −0.06568 (19) | 0.0408 (7) | |
| C4 | 1.1709 (2) | −0.1336 (3) | −0.1275 (2) | 0.0522 (8) | |
| H4A | 1.2463 | −0.1185 | −0.1187 | 0.063* | |
| H4B | 1.1479 | −0.1161 | −0.1982 | 0.063* | |
| C5 | 0.9742 (2) | 0.3236 (4) | 0.1053 (2) | 0.0483 (8) | |
| H5A | 0.9906 | 0.4287 | 0.0819 | 0.058* | |
| H5B | 1.0030 | 0.3146 | 0.1752 | 0.058* | |
| C6 | 0.8543 (2) | 0.3047 (3) | 0.0998 (2) | 0.0456 (7) | |
| C7 | 0.8054 (2) | 0.3422 (4) | −0.0065 (2) | 0.0602 (9) | |
| H7A | 0.8324 | 0.2704 | −0.0536 | 0.090* | |
| H7B | 0.8224 | 0.4490 | −0.0237 | 0.090* | |
| H7C | 0.7307 | 0.3308 | −0.0091 | 0.090* | |
| C8 | 0.8112 (3) | 0.4183 (4) | 0.1746 (3) | 0.0705 (10) | |
| H8A | 0.7364 | 0.4078 | 0.1711 | 0.106* | |
| H8B | 0.8290 | 0.5251 | 0.1582 | 0.106* | |
| H8C | 0.8411 | 0.3935 | 0.2416 | 0.106* | |
| C9 | 0.4617 (2) | 0.2110 (3) | −0.00971 (19) | 0.0380 (7) | |
| C10 | 0.47112 (19) | 0.0524 (3) | 0.02548 (18) | 0.0361 (7) | |
| C11 | 0.5739 (2) | 0.0028 (3) | −0.11235 (19) | 0.0386 (7) | |
| C12 | 0.6346 (2) | −0.1106 (3) | −0.1700 (2) | 0.0460 (8) | |
| H12A | 0.7083 | −0.1023 | −0.1463 | 0.055* | |
| H12B | 0.6267 | −0.0816 | −0.2408 | 0.055* | |
| C13 | 0.3987 (2) | 0.3244 (3) | 0.0462 (2) | 0.0443 (7) | |
| H13A | 0.3267 | 0.3235 | 0.0162 | 0.053* | |
| H13B | 0.4261 | 0.4306 | 0.0394 | 0.053* | |
| C14 | 0.4010 (2) | 0.2827 (3) | 0.1591 (2) | 0.0448 (8) | |
| C15 | 0.5115 (3) | 0.3042 (4) | 0.2106 (2) | 0.0646 (10) | |
| H15A | 0.5326 | 0.4127 | 0.2047 | 0.097* | |
| H15B | 0.5590 | 0.2368 | 0.1790 | 0.097* | |
| H15C | 0.5124 | 0.2767 | 0.2807 | 0.097* | |
| C16 | 0.3261 (3) | 0.3920 (4) | 0.2079 (2) | 0.0652 (10) | |
| H16A | 0.3267 | 0.3663 | 0.2782 | 0.098* | |
| H16B | 0.2566 | 0.3788 | 0.1754 | 0.098* | |
| H16C | 0.3480 | 0.5000 | 0.2010 | 0.098* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| N1 | 0.0418 (15) | 0.0440 (15) | 0.0675 (17) | −0.0085 (12) | 0.0070 (13) | −0.0044 (13) |
| N2 | 0.0442 (14) | 0.0409 (15) | 0.0702 (17) | −0.0060 (12) | 0.0122 (12) | −0.0011 (13) |
| N3 | 0.0583 (16) | 0.0392 (14) | 0.0445 (14) | −0.0001 (12) | 0.0117 (12) | 0.0062 (11) |
| N4 | 0.0593 (16) | 0.0392 (15) | 0.0442 (14) | −0.0027 (12) | 0.0133 (12) | 0.0036 (11) |
| C1 | 0.0385 (16) | 0.0370 (17) | 0.0416 (16) | −0.0029 (13) | −0.0025 (13) | 0.0016 (13) |
| C2 | 0.0322 (15) | 0.0314 (15) | 0.0402 (16) | −0.0019 (11) | −0.0026 (12) | 0.0033 (11) |
| C3 | 0.0413 (16) | 0.0387 (17) | 0.0424 (16) | −0.0017 (14) | 0.0045 (13) | 0.0057 (13) |
| C4 | 0.0490 (18) | 0.050 (2) | 0.0595 (19) | 0.0021 (15) | 0.0164 (15) | 0.0029 (15) |
| C5 | 0.0491 (18) | 0.0458 (18) | 0.0488 (17) | −0.0039 (15) | −0.0014 (14) | −0.0070 (14) |
| C6 | 0.0457 (17) | 0.0406 (17) | 0.0507 (17) | 0.0024 (14) | 0.0067 (14) | −0.0028 (14) |
| C7 | 0.055 (2) | 0.052 (2) | 0.071 (2) | 0.0062 (16) | −0.0062 (16) | 0.0042 (17) |
| C8 | 0.068 (2) | 0.061 (2) | 0.084 (3) | 0.0038 (19) | 0.0189 (19) | −0.0165 (19) |
| C9 | 0.0411 (16) | 0.0354 (17) | 0.0370 (15) | −0.0034 (13) | 0.0004 (12) | 0.0020 (13) |
| C10 | 0.0367 (15) | 0.0380 (17) | 0.0331 (15) | −0.0046 (12) | 0.0008 (11) | 0.0016 (11) |
| C11 | 0.0412 (16) | 0.0380 (17) | 0.0366 (15) | −0.0045 (13) | 0.0033 (12) | 0.0039 (13) |
| C12 | 0.0470 (17) | 0.0492 (19) | 0.0429 (16) | 0.0018 (14) | 0.0091 (13) | 0.0031 (14) |
| C13 | 0.0459 (17) | 0.0349 (16) | 0.0518 (17) | −0.0025 (13) | 0.0030 (13) | 0.0026 (14) |
| C14 | 0.0489 (18) | 0.0416 (18) | 0.0438 (16) | 0.0031 (14) | 0.0053 (14) | −0.0027 (13) |
| C15 | 0.064 (2) | 0.061 (2) | 0.065 (2) | −0.0014 (18) | −0.0099 (17) | −0.0108 (18) |
| C16 | 0.081 (2) | 0.060 (2) | 0.057 (2) | 0.0161 (19) | 0.0187 (18) | −0.0003 (17) |
| N1—C1 | 1.322 (3) | C8—H8A | 0.9600 |
| N1—N2 | 1.386 (3) | C8—H8B | 0.9600 |
| N2—C3 | 1.311 (3) | C8—H8C | 0.9600 |
| N3—C9 | 1.312 (3) | C9—C10 | 1.420 (4) |
| N3—N4 | 1.382 (3) | C9—C13 | 1.495 (4) |
| N4—C11 | 1.323 (4) | C10—C10ii | 1.373 (5) |
| C1—C2 | 1.413 (3) | C10—C11ii | 1.419 (3) |
| C1—C5 | 1.482 (4) | C11—C10ii | 1.419 (3) |
| C2—C2i | 1.371 (5) | C11—C12 | 1.491 (4) |
| C2—C3i | 1.423 (3) | C12—C14ii | 1.534 (4) |
| C3—C2i | 1.423 (3) | C12—H12A | 0.9700 |
| C3—C4 | 1.485 (4) | C12—H12B | 0.9700 |
| C4—C6i | 1.533 (4) | C13—C14 | 1.541 (4) |
| C4—H4A | 0.9700 | C13—H13A | 0.9700 |
| C4—H4B | 0.9700 | C13—H13B | 0.9700 |
| C5—C6 | 1.540 (4) | C14—C16 | 1.521 (4) |
| C5—H5A | 0.9700 | C14—C15 | 1.525 (4) |
| C5—H5B | 0.9700 | C14—C12ii | 1.534 (4) |
| C6—C8 | 1.524 (4) | C15—H15A | 0.9600 |
| C6—C7 | 1.525 (4) | C15—H15B | 0.9600 |
| C6—C4i | 1.533 (4) | C15—H15C | 0.9600 |
| C7—H7A | 0.9600 | C16—H16A | 0.9600 |
| C7—H7B | 0.9600 | C16—H16B | 0.9600 |
| C7—H7C | 0.9600 | C16—H16C | 0.9600 |
| C1—N1—N2 | 120.5 (2) | H8A—C8—H8C | 109.5 |
| C3—N2—N1 | 120.4 (2) | H8B—C8—H8C | 109.5 |
| C9—N3—N4 | 120.4 (2) | N3—C9—C10 | 121.3 (2) |
| C11—N4—N3 | 120.6 (2) | N3—C9—C13 | 120.5 (2) |
| N1—C1—C2 | 121.0 (2) | C10—C9—C13 | 118.2 (2) |
| N1—C1—C5 | 120.4 (2) | C10ii—C10—C11ii | 118.1 (3) |
| C2—C1—C5 | 118.6 (2) | C10ii—C10—C9 | 118.5 (3) |
| C2i—C2—C1 | 118.5 (3) | C11ii—C10—C9 | 123.4 (2) |
| C2i—C2—C3i | 118.3 (3) | N4—C11—C10ii | 121.0 (2) |
| C1—C2—C3i | 123.2 (2) | N4—C11—C12 | 120.2 (2) |
| N2—C3—C2i | 121.2 (2) | C10ii—C11—C12 | 118.8 (2) |
| N2—C3—C4 | 120.5 (2) | C11—C12—C14ii | 112.6 (2) |
| C2i—C3—C4 | 118.2 (2) | C11—C12—H12A | 109.1 |
| C3—C4—C6i | 113.0 (2) | C14ii—C12—H12A | 109.1 |
| C3—C4—H4A | 109.0 | C11—C12—H12B | 109.1 |
| C6i—C4—H4A | 109.0 | C14ii—C12—H12B | 109.1 |
| C3—C4—H4B | 109.0 | H12A—C12—H12B | 107.8 |
| C6i—C4—H4B | 109.0 | C9—C13—C14 | 112.2 (2) |
| H4A—C4—H4B | 107.8 | C9—C13—H13A | 109.2 |
| C1—C5—C6 | 113.1 (2) | C14—C13—H13A | 109.2 |
| C1—C5—H5A | 109.0 | C9—C13—H13B | 109.2 |
| C6—C5—H5A | 109.0 | C14—C13—H13B | 109.2 |
| C1—C5—H5B | 109.0 | H13A—C13—H13B | 107.9 |
| C6—C5—H5B | 109.0 | C16—C14—C15 | 109.4 (3) |
| H5A—C5—H5B | 107.8 | C16—C14—C12ii | 109.2 (2) |
| C8—C6—C7 | 109.5 (3) | C15—C14—C12ii | 110.0 (2) |
| C8—C6—C4i | 109.7 (2) | C16—C14—C13 | 108.9 (2) |
| C7—C6—C4i | 110.0 (2) | C15—C14—C13 | 110.0 (2) |
| C8—C6—C5 | 109.0 (2) | C12ii—C14—C13 | 109.3 (2) |
| C7—C6—C5 | 110.1 (2) | C14—C15—H15A | 109.5 |
| C4i—C6—C5 | 108.6 (2) | C14—C15—H15B | 109.5 |
| C6—C7—H7A | 109.5 | H15A—C15—H15B | 109.5 |
| C6—C7—H7B | 109.5 | C14—C15—H15C | 109.5 |
| H7A—C7—H7B | 109.5 | H15A—C15—H15C | 109.5 |
| C6—C7—H7C | 109.5 | H15B—C15—H15C | 109.5 |
| H7A—C7—H7C | 109.5 | C14—C16—H16A | 109.5 |
| H7B—C7—H7C | 109.5 | C14—C16—H16B | 109.5 |
| C6—C8—H8A | 109.5 | H16A—C16—H16B | 109.5 |
| C6—C8—H8B | 109.5 | C14—C16—H16C | 109.5 |
| H8A—C8—H8B | 109.5 | H16A—C16—H16C | 109.5 |
| C6—C8—H8C | 109.5 | H16B—C16—H16C | 109.5 |
| Symmetry codes: (i) −x+2, −y, −z; (ii) −x+1, −y, −z. |
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It is well known that six-membered nitrogen-containing heterocycles are abundant in numerous natural products that exhibit important biological properties. For example, cinnolines and their derivatives are widely used as agrochemical and pharmaceutical drugs (Ischikawa et al., 1992; Labovitz et al., 1990; Mizutani, Shiroshita, Okuda et al., 1989; Patterson, 1992; Coghlan et al., 1989; Mizutani, Shiroshita, Sakaki et al., 1989; Munro & Bit, 1987). They can act as microbicides, pollen suppressants, fungicides and herbicides in agrochemistry. They can also be used as bactericides in pharmaceutical industry (Inoue et al., 1993; Tutsumi et al., 1992; Yokomoto et al., 1992; Miyamoto et al., 1990). The chemistry of cinnolines has received much attention based on the above facts.
The asymmetric unit of the title compound contains two-halves of centrosymmetric molecules (Fig. 1). The bond lengths (Allen et al., 1987) and angles are within normal ranges. The pyridazine rings A (N1/N2/C1-C3/C2A) and C (N3/N4/C9-C11/C10B) are, of course, planar and they are oriented at a dihedral angle of 43.89 (3)° [symmetry codes: (A) 2 - x, -y, -z; (B) 1 - x, -y, -z]. The cyclohexene rings B (C1/C2/C5/C6/C3A/C4A) and D (C9/C10/C13/C14/C11B/C12B), having total puckering amplitudes, QT, of 0.579 (3) and 0.566 Å, respectively, half-chair conformations [φ = -72.92 (3)° and θ = 103.84 (4)°; φ = 110.31 (4)° and θ = 74.14 (4)°] (Cremer & Pople, 1975) [symmetry codes: (A) 2 - x, -y, -z; (B) 1 - x, -y, -z].