organic compounds
1-[2,6-Dichloro-4-(trifluoromethyl)phenyl]-3,4-dimethylpyrano[2,3-c]pyrazol-6(1H)-one
aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, bDepartment of Chemistry, P.A. College of Engineering, Mangalore 574 153, India, and cDepartment of Chemistry, Mangalore University, Mangalagangotri 574 199, Mangalore, India
*Correspondence e-mail: hkfun@usm.my
In the title compound, C15H9Cl2F3N2O2, the 1,6-dihydropyrano[2,3-c]pyrazole ring system is almost planar, with a maximum deviation of 0.0226 (14) Å, and forms a dihedral angle of 69.90 (6)° with the benzene ring. In the crystal, molecules are linked into a helical chain along the c axis by C—H⋯O hydrogen bonds.
Related literature
For background to and the biological activity of pyrazolone derivatives, see: Kokura et al. (2005); Sarojini et al. (2010); Vaid et al. (1986). For related structures, see: Ramsay & Steel (1985); Ahmad et al. (2011). For bond-length data, see: Allen et al. (1987). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S1600536812029789/is5160sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812029789/is5160Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536812029789/is5160Isup3.cml
(2,6-Dichloro-4-trifluoromethyl)phenyl hydrazine (1.225 g, 0.005 mol) was added to ethyl acetoacetate (1.3 g, 0.01 mol) and charged in a microwave for 3 minutes at 360 W. The reaction mixture was quenched into ether and kept for some time to get the residue. The residue was recrystallized by slow evaporation from ethanol to give block-shaped orange crystals suitable for X-ray diffraction. M.p. = 431 K.
All H atoms were positioned geometrically and were refined with a riding model with Uiso(H) = 1.2 or 1.5 Ueq(C) (C—H = 0.95 or 0.98 Å). A rotating group model was applied to the methyl groups.
Pyrazolone moiety is a pyrazole derivative, containing a five-membered lactam ring with two nitrogen atoms and a ketone group in the same molecule. Edaravone, 3-methyl-1-phenyl-2-pyrazolin-5-one, is a strong novel
scavenger and was used for treatment of patients with acute brain infarction (Kokura et al., 2005). The radical scavenging capacity and molecular binding activities of various derivatives of pyrazol-5-ols were reported (Sarojini et al., 2010). In an attempt to synthesize pyrazolone derivative, the title compound was formed when ethyl acetoacetate was taken in 1: 2 molar ratio. Similar product formation was reported by Vaid et al. (1986). The of 3,4-dimethyl-1-(2-pyridyl)pyrano[2,3-c]pyrazol-6(1H)-one was reported by Ramsay & Steel (1985) and the structure of 3,4-dimethyl-1-phenylpyrano[2,3-c]-pyrazol-6(1H)-one was reported by Ahmad et al. (2011). The title compound 1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-3,4- dimethylpyrano[2,3-c]pyrazol-6(1H)-one [C15H9Cl2F3N2O2], was prepared by the reaction of 2,6-dichloro-4-trifluoromethyl-phenyl hydrazine with excess of ethyl acetoacetate.In the title compound, Fig. 1, the 1,6-dihydropyrano[2,3-c]pyrazole ring system (C1–C5/N1/N2/C6/O1) is almost planar with the maximum deviation of 0.0226 (14) Å at atom C2 and forms a dihedral angle of 69.90 (6)° with the benzene ring (C7–C12). Bond lengths (Allen et al., 1987) and angles are within the normal ranges.
In the crystal packing as shown in Fig. 2, the molecules are linked into chains along the c axis by the intermolecular C11—H11A···O2 hydrogen bonds (Table 1).
For background to and the biological activity of pyrazolone derivatives, see: Kokura et al. (2005); Sarojini et al. (2010); Vaid et al. (1986). For related structures, see: Ramsay & Steel (1985); Ahmad et al. (2011). For bond-length data, see: Allen et al. (1987). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).C15H9Cl2F3N2O2 | F(000) = 1520 |
Mr = 377.14 | Dx = 1.662 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 9873 reflections |
a = 13.3348 (2) Å | θ = 2.5–32.6° |
b = 14.2045 (2) Å | µ = 0.48 mm−1 |
c = 15.9132 (3) Å | T = 100 K |
V = 3014.19 (8) Å3 | Block, orange |
Z = 8 | 0.44 × 0.31 × 0.26 mm |
Bruker SMART APEXII CCD area-detector diffractometer | 4382 independent reflections |
Radiation source: fine-focus sealed tube | 3706 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
φ and ω scans | θmax = 30.0°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −18→18 |
Tmin = 0.819, Tmax = 0.888 | k = −19→19 |
24894 measured reflections | l = −22→20 |
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)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.096 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0445P)2 + 2.1563P] where P = (Fo2 + 2Fc2)/3 |
4382 reflections | (Δ/σ)max = 0.001 |
219 parameters | Δρmax = 0.43 e Å−3 |
0 restraints | Δρmin = −0.51 e Å−3 |
C15H9Cl2F3N2O2 | V = 3014.19 (8) Å3 |
Mr = 377.14 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 13.3348 (2) Å | µ = 0.48 mm−1 |
b = 14.2045 (2) Å | T = 100 K |
c = 15.9132 (3) Å | 0.44 × 0.31 × 0.26 mm |
Bruker SMART APEXII CCD area-detector diffractometer | 4382 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 3706 reflections with I > 2σ(I) |
Tmin = 0.819, Tmax = 0.888 | Rint = 0.030 |
24894 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.096 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.43 e Å−3 |
4382 reflections | Δρmin = −0.51 e Å−3 |
219 parameters |
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. |
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 | ||
Cl1 | 0.05786 (3) | 0.14096 (3) | 0.71268 (2) | 0.02478 (10) | |
Cl2 | 0.32815 (3) | 0.42169 (3) | 0.68567 (2) | 0.02497 (10) | |
F1 | 0.01024 (12) | 0.35846 (9) | 0.97088 (8) | 0.0559 (4) | |
F2 | 0.14301 (8) | 0.44227 (10) | 0.97926 (7) | 0.0426 (3) | |
F3 | 0.01721 (9) | 0.49137 (8) | 0.91002 (6) | 0.0399 (3) | |
O1 | 0.20606 (8) | 0.33302 (7) | 0.52607 (6) | 0.0197 (2) | |
O2 | 0.18623 (9) | 0.41836 (8) | 0.41029 (7) | 0.0260 (2) | |
N1 | 0.29995 (9) | 0.15794 (8) | 0.66209 (8) | 0.0187 (2) | |
N2 | 0.23949 (9) | 0.23515 (8) | 0.64239 (7) | 0.0181 (2) | |
C1 | 0.23104 (11) | 0.35320 (10) | 0.44100 (9) | 0.0202 (3) | |
C2 | 0.30521 (11) | 0.29344 (10) | 0.40143 (9) | 0.0209 (3) | |
H2A | 0.3237 | 0.3070 | 0.3451 | 0.025* | |
C3 | 0.35023 (11) | 0.21887 (10) | 0.43997 (9) | 0.0189 (3) | |
C4 | 0.32303 (10) | 0.20139 (10) | 0.52589 (9) | 0.0166 (3) | |
C5 | 0.34852 (11) | 0.13725 (10) | 0.59193 (9) | 0.0180 (3) | |
C6 | 0.25427 (11) | 0.26101 (9) | 0.56213 (9) | 0.0174 (3) | |
C7 | 0.19107 (10) | 0.28382 (9) | 0.70869 (9) | 0.0167 (3) | |
C8 | 0.10967 (10) | 0.24338 (9) | 0.75021 (9) | 0.0173 (2) | |
C9 | 0.06951 (11) | 0.28556 (10) | 0.82140 (9) | 0.0184 (3) | |
H9A | 0.0149 | 0.2574 | 0.8503 | 0.022* | |
C10 | 0.11052 (11) | 0.36948 (10) | 0.84946 (9) | 0.0176 (3) | |
C11 | 0.18835 (11) | 0.41405 (10) | 0.80713 (9) | 0.0189 (3) | |
H11A | 0.2135 | 0.4730 | 0.8258 | 0.023* | |
C12 | 0.22825 (10) | 0.37016 (10) | 0.73692 (9) | 0.0179 (3) | |
C13 | 0.42522 (12) | 0.15731 (12) | 0.39669 (10) | 0.0247 (3) | |
H13A | 0.4314 | 0.1766 | 0.3378 | 0.037* | |
H13B | 0.4029 | 0.0916 | 0.3994 | 0.037* | |
H13C | 0.4905 | 0.1634 | 0.4245 | 0.037* | |
C14 | 0.41785 (12) | 0.05479 (11) | 0.59007 (10) | 0.0227 (3) | |
H14A | 0.4190 | 0.0247 | 0.6455 | 0.034* | |
H14B | 0.4856 | 0.0761 | 0.5755 | 0.034* | |
H14C | 0.3946 | 0.0094 | 0.5480 | 0.034* | |
C15 | 0.07067 (11) | 0.41500 (10) | 0.92787 (9) | 0.0199 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.02666 (18) | 0.01914 (17) | 0.02854 (19) | −0.00419 (13) | 0.00424 (15) | −0.00636 (13) |
Cl2 | 0.02532 (18) | 0.02462 (18) | 0.02499 (19) | −0.00624 (13) | 0.00913 (14) | −0.00204 (13) |
F1 | 0.0876 (10) | 0.0374 (6) | 0.0427 (7) | −0.0230 (6) | 0.0449 (7) | −0.0153 (5) |
F2 | 0.0261 (5) | 0.0781 (9) | 0.0235 (5) | 0.0124 (5) | −0.0059 (4) | −0.0203 (5) |
F3 | 0.0531 (7) | 0.0427 (6) | 0.0240 (5) | 0.0310 (5) | −0.0038 (5) | −0.0093 (4) |
O1 | 0.0229 (5) | 0.0196 (5) | 0.0166 (5) | 0.0040 (4) | 0.0025 (4) | 0.0000 (4) |
O2 | 0.0315 (6) | 0.0244 (5) | 0.0221 (5) | 0.0033 (4) | 0.0003 (5) | 0.0033 (4) |
N1 | 0.0205 (6) | 0.0167 (5) | 0.0190 (6) | 0.0034 (4) | 0.0012 (5) | −0.0010 (4) |
N2 | 0.0219 (6) | 0.0168 (5) | 0.0156 (5) | 0.0033 (4) | 0.0039 (5) | −0.0012 (4) |
C1 | 0.0234 (7) | 0.0205 (6) | 0.0169 (6) | −0.0023 (5) | 0.0004 (5) | 0.0000 (5) |
C2 | 0.0216 (7) | 0.0246 (7) | 0.0166 (6) | −0.0021 (5) | 0.0025 (5) | −0.0023 (5) |
C3 | 0.0173 (6) | 0.0214 (6) | 0.0180 (6) | −0.0031 (5) | 0.0024 (5) | −0.0052 (5) |
C4 | 0.0160 (6) | 0.0171 (6) | 0.0168 (6) | −0.0003 (5) | 0.0019 (5) | −0.0028 (5) |
C5 | 0.0174 (6) | 0.0169 (6) | 0.0196 (7) | −0.0006 (5) | 0.0001 (5) | −0.0037 (5) |
C6 | 0.0193 (6) | 0.0162 (6) | 0.0167 (6) | 0.0000 (5) | 0.0014 (5) | −0.0017 (5) |
C7 | 0.0182 (6) | 0.0171 (6) | 0.0147 (6) | 0.0033 (5) | 0.0013 (5) | −0.0016 (5) |
C8 | 0.0181 (6) | 0.0158 (6) | 0.0179 (6) | 0.0003 (5) | −0.0001 (5) | −0.0013 (5) |
C9 | 0.0181 (6) | 0.0190 (6) | 0.0182 (6) | 0.0014 (5) | 0.0029 (5) | 0.0007 (5) |
C10 | 0.0195 (6) | 0.0180 (6) | 0.0152 (6) | 0.0050 (5) | 0.0022 (5) | −0.0014 (5) |
C11 | 0.0218 (6) | 0.0167 (6) | 0.0182 (6) | 0.0010 (5) | 0.0018 (5) | −0.0027 (5) |
C12 | 0.0183 (6) | 0.0181 (6) | 0.0174 (6) | 0.0001 (5) | 0.0038 (5) | 0.0001 (5) |
C13 | 0.0230 (7) | 0.0294 (8) | 0.0216 (7) | 0.0033 (6) | 0.0062 (6) | −0.0045 (6) |
C14 | 0.0231 (7) | 0.0208 (7) | 0.0241 (7) | 0.0059 (5) | 0.0004 (6) | −0.0032 (5) |
C15 | 0.0229 (7) | 0.0212 (6) | 0.0157 (6) | 0.0027 (5) | 0.0025 (5) | −0.0020 (5) |
Cl1—C8 | 1.7176 (14) | C4—C5 | 1.432 (2) |
Cl2—C12 | 1.7249 (14) | C5—C14 | 1.4926 (19) |
F1—C15 | 1.3277 (18) | C7—C8 | 1.3946 (19) |
F2—C15 | 1.3227 (18) | C7—C12 | 1.3971 (19) |
F3—C15 | 1.3288 (17) | C8—C9 | 1.3890 (19) |
O1—C6 | 1.3375 (17) | C9—C10 | 1.386 (2) |
O1—C1 | 1.4233 (17) | C9—H9A | 0.9500 |
O2—C1 | 1.2053 (18) | C10—C11 | 1.390 (2) |
N1—C5 | 1.3238 (18) | C10—C15 | 1.5023 (19) |
N1—N2 | 1.3967 (16) | C11—C12 | 1.3858 (19) |
N2—C6 | 1.3436 (18) | C11—H11A | 0.9500 |
N2—C7 | 1.4170 (17) | C13—H13A | 0.9800 |
C1—C2 | 1.448 (2) | C13—H13B | 0.9800 |
C2—C3 | 1.363 (2) | C13—H13C | 0.9800 |
C2—H2A | 0.9500 | C14—H14A | 0.9800 |
C3—C4 | 1.436 (2) | C14—H14B | 0.9800 |
C3—C13 | 1.496 (2) | C14—H14C | 0.9800 |
C4—C6 | 1.3749 (18) | ||
C6—O1—C1 | 116.71 (11) | C10—C9—H9A | 120.6 |
C5—N1—N2 | 105.51 (12) | C8—C9—H9A | 120.6 |
C6—N2—N1 | 110.08 (11) | C9—C10—C11 | 122.04 (13) |
C6—N2—C7 | 129.89 (12) | C9—C10—C15 | 119.89 (13) |
N1—N2—C7 | 118.62 (11) | C11—C10—C15 | 118.07 (13) |
O2—C1—O1 | 115.10 (13) | C12—C11—C10 | 118.21 (13) |
O2—C1—C2 | 127.79 (14) | C12—C11—H11A | 120.9 |
O1—C1—C2 | 117.11 (12) | C10—C11—H11A | 120.9 |
C3—C2—C1 | 124.11 (13) | C11—C12—C7 | 121.19 (13) |
C3—C2—H2A | 117.9 | C11—C12—Cl2 | 119.14 (11) |
C1—C2—H2A | 117.9 | C7—C12—Cl2 | 119.64 (11) |
C2—C3—C4 | 116.84 (13) | C3—C13—H13A | 109.5 |
C2—C3—C13 | 122.77 (14) | C3—C13—H13B | 109.5 |
C4—C3—C13 | 120.39 (13) | H13A—C13—H13B | 109.5 |
C6—C4—C5 | 104.03 (12) | C3—C13—H13C | 109.5 |
C6—C4—C3 | 117.46 (13) | H13A—C13—H13C | 109.5 |
C5—C4—C3 | 138.49 (13) | H13B—C13—H13C | 109.5 |
N1—C5—C4 | 111.20 (12) | C5—C14—H14A | 109.5 |
N1—C5—C14 | 119.61 (13) | C5—C14—H14B | 109.5 |
C4—C5—C14 | 129.18 (13) | H14A—C14—H14B | 109.5 |
O1—C6—N2 | 123.12 (12) | C5—C14—H14C | 109.5 |
O1—C6—C4 | 127.72 (13) | H14A—C14—H14C | 109.5 |
N2—C6—C4 | 109.15 (12) | H14B—C14—H14C | 109.5 |
C8—C7—C12 | 119.05 (12) | F2—C15—F1 | 107.52 (13) |
C8—C7—N2 | 120.43 (12) | F2—C15—F3 | 106.52 (13) |
C12—C7—N2 | 120.40 (12) | F1—C15—F3 | 106.16 (13) |
C9—C8—C7 | 120.59 (13) | F2—C15—C10 | 112.43 (12) |
C9—C8—Cl1 | 119.59 (11) | F1—C15—C10 | 112.49 (12) |
C7—C8—Cl1 | 119.82 (11) | F3—C15—C10 | 111.32 (12) |
C10—C9—C8 | 118.81 (13) | ||
C5—N1—N2—C6 | −1.53 (16) | C3—C4—C6—N2 | −178.89 (12) |
C5—N1—N2—C7 | −169.29 (12) | C6—N2—C7—C8 | 122.18 (17) |
C6—O1—C1—O2 | 179.89 (13) | N1—N2—C7—C8 | −72.87 (17) |
C6—O1—C1—C2 | 0.64 (18) | C6—N2—C7—C12 | −62.0 (2) |
O2—C1—C2—C3 | −177.74 (15) | N1—N2—C7—C12 | 102.97 (16) |
O1—C1—C2—C3 | 1.4 (2) | C12—C7—C8—C9 | −3.5 (2) |
C1—C2—C3—C4 | −1.7 (2) | N2—C7—C8—C9 | 172.37 (13) |
C1—C2—C3—C13 | 178.78 (14) | C12—C7—C8—Cl1 | 175.99 (11) |
C2—C3—C4—C6 | −0.07 (19) | N2—C7—C8—Cl1 | −8.11 (19) |
C13—C3—C4—C6 | 179.51 (13) | C7—C8—C9—C10 | 1.3 (2) |
C2—C3—C4—C5 | −178.26 (16) | Cl1—C8—C9—C10 | −178.27 (11) |
C13—C3—C4—C5 | 1.3 (3) | C8—C9—C10—C11 | 2.0 (2) |
N2—N1—C5—C4 | 1.45 (16) | C8—C9—C10—C15 | −178.05 (13) |
N2—N1—C5—C14 | −177.79 (12) | C9—C10—C11—C12 | −2.9 (2) |
C6—C4—C5—N1 | −0.87 (16) | C15—C10—C11—C12 | 177.19 (13) |
C3—C4—C5—N1 | 177.48 (16) | C10—C11—C12—C7 | 0.5 (2) |
C6—C4—C5—C14 | 178.29 (14) | C10—C11—C12—Cl2 | −177.47 (11) |
C3—C4—C5—C14 | −3.4 (3) | C8—C7—C12—C11 | 2.6 (2) |
C1—O1—C6—N2 | 178.79 (13) | N2—C7—C12—C11 | −173.26 (13) |
C1—O1—C6—C4 | −2.6 (2) | C8—C7—C12—Cl2 | −179.39 (11) |
N1—N2—C6—O1 | 179.89 (12) | N2—C7—C12—Cl2 | 4.71 (19) |
C7—N2—C6—O1 | −14.2 (2) | C9—C10—C15—F2 | 133.24 (15) |
N1—N2—C6—C4 | 1.02 (16) | C11—C10—C15—F2 | −46.84 (18) |
C7—N2—C6—C4 | 166.98 (14) | C9—C10—C15—F1 | 11.7 (2) |
C5—C4—C6—O1 | −178.93 (14) | C11—C10—C15—F1 | −168.40 (14) |
C3—C4—C6—O1 | 2.3 (2) | C9—C10—C15—F3 | −107.33 (16) |
C5—C4—C6—N2 | −0.13 (15) | C11—C10—C15—F3 | 72.59 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
C11—H11A···O2i | 0.95 | 2.44 | 3.3405 (18) | 157 |
Symmetry code: (i) −x+1/2, −y+1, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C15H9Cl2F3N2O2 |
Mr | 377.14 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 100 |
a, b, c (Å) | 13.3348 (2), 14.2045 (2), 15.9132 (3) |
V (Å3) | 3014.19 (8) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.48 |
Crystal size (mm) | 0.44 × 0.31 × 0.26 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.819, 0.888 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 24894, 4382, 3706 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.096, 1.03 |
No. of reflections | 4382 |
No. of parameters | 219 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.43, −0.51 |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C11—H11A···O2i | 0.95 | 2.44 | 3.3405 (18) | 157 |
Symmetry code: (i) −x+1/2, −y+1, z+1/2. |
Acknowledgements
HKF and WSL thank Universiti Sains Malaysia (USM) for the Research University Grant (1001/PFIZIK/811160). WSL also thanks the Malaysian Government and USM for the position as Research Officer under the Research University Grant (1001/PFIZIK/811160). BKS gratefully acknowledges the Department of Atomic Energy (DAE)/BRNS, Government of India, for providing financial assistance for the BRNS project (No. 2011/34/20-BRNS/0846).
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Pyrazolone moiety is a pyrazole derivative, containing a five-membered lactam ring with two nitrogen atoms and a ketone group in the same molecule. Edaravone, 3-methyl-1-phenyl-2-pyrazolin-5-one, is a strong novel free radical scavenger and was used for treatment of patients with acute brain infarction (Kokura et al., 2005). The radical scavenging capacity and molecular binding activities of various derivatives of pyrazol-5-ols were reported (Sarojini et al., 2010). In an attempt to synthesize pyrazolone derivative, the title compound was formed when ethyl acetoacetate was taken in 1: 2 molar ratio. Similar product formation was reported by Vaid et al. (1986). The crystal structure of 3,4-dimethyl-1-(2-pyridyl)pyrano[2,3-c]pyrazol-6(1H)-one was reported by Ramsay & Steel (1985) and the structure of 3,4-dimethyl-1-phenylpyrano[2,3-c]-pyrazol-6(1H)-one was reported by Ahmad et al. (2011). The title compound 1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-3,4- dimethylpyrano[2,3-c]pyrazol-6(1H)-one [C15H9Cl2F3N2O2], was prepared by the reaction of 2,6-dichloro-4-trifluoromethyl-phenyl hydrazine with excess of ethyl acetoacetate.
In the title compound, Fig. 1, the 1,6-dihydropyrano[2,3-c]pyrazole ring system (C1–C5/N1/N2/C6/O1) is almost planar with the maximum deviation of 0.0226 (14) Å at atom C2 and forms a dihedral angle of 69.90 (6)° with the benzene ring (C7–C12). Bond lengths (Allen et al., 1987) and angles are within the normal ranges.
In the crystal packing as shown in Fig. 2, the molecules are linked into chains along the c axis by the intermolecular C11—H11A···O2 hydrogen bonds (Table 1).