





Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536810040596/hb5673sup1.cif |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S1600536810040596/hb5673Isup2.hkl |
CCDC reference: 799599
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean
(C-C) = 0.002 Å
- R factor = 0.043
- wR factor = 0.113
- Data-to-parameter ratio = 29.3
checkCIF/PLATON results
No syntax errors found
Alert level C SHFSU01_ALERT_2_C Test not performed. _refine_ls_shift/su_max and _refine_ls_shift/esd_max not present. Absolute value of the parameter shift to su ratio given 0.001 PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) ..... 1 PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L= 0.600 5 PLAT142_ALERT_4_C su on b - Axis Small or Missing (x 100000) ..... 1 Ang. PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L= 0.600 15
Alert level G PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels .......... 1
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 3 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
The compound has been synthesized using the method available in the literature (Ragavan et al., 2009) and recrystallized using an ethanol-chloroform 1:1 mixture to generate colourless needles of (I). Yield: 58%. M.Pt: 475 K.
The hydrogen atoms bound to C atoms were positioned geometrically [C–H = 0.9300 to 0.9600 Å] with Uiso(H) =1.2 or 1.5Uiso(C). The hydrogen atom attached to the N2 atom was located from the difference map and refined freely.
Antibacterial and antifungal activities of the azoles are most widely studied and some of them are in clinical practice as anti-microbial agents. However, the azole-resistant strain had led to the development of new antimicrobial compounds. In particular pyrazole derivatives are extensively studied and used as antimicrobial agents. Pyrazole is an important class of heterocyclic compounds and many pyrazole derivatives are reported to have the broad spectrum of biological properties, such as anti-inflammatory, antifungal, herbicidal, anti-tumour, cytotoxic, molecular modelling, and antiviral activities. Pyrazole derivatives also act as antiangiogenic agents, A3 adenosine receptor antagonists, neuropeptide YY5 receptor antagonists, kinase inhibitor for treatment of type 2 diabetes, hyperlipidemia, obesity, and thrombopiotinmimetics. Recently urea derivatives of pyrazoles have been reported as potent inhibitors of p38 kinase. Since the high electronegativity of halogens (particularly chlorine and fluorine) in the aromatic part of the drug molecules play an important role in enhancing their biological activity, we are interested to have 4-fluoro or 4-chloro substitution in the aryls of 1,5-diaryl pyrazoles. As part of our on-going research aiming the synthesis of new antimicrobial compounds, we have reported the synthesis of novel pyrazole derivatives and their microbial activities (Ragavan et al., 2009; 2010). The structure of the title compound is presented here. The synthesis lead to the enol form of the compound (see Ragavan et al., 2009). However the single crystal structure determination gives the keto form. Therefore the compound undergoes an enol-to-keto tautomerism during crystallization. The interconversion of the two forms involves the movement of a proton and the shifting of bonding electrons; hence, the isomerism qualifies as tautomerism (Fig. 2)
The asymmetric unit of the title compound, (Fig. 1), consists of three rings, namely fluorophenyl (F1/C1–C6), 5-3methyl-2,5dihydro-1H-pyrazol-3-one (N1/N2/C7–C9/O1/C16) and phenylthiol (S1/C10–C15).The 1-(4-fluorophenyl)-3-methyl-4-(phenylthio)-1H-pyrazol-5-ol undergoes an enol-to-ketotautomerism during the crystallization process (Fig. 2). The 1H-pyrazole-5-one ring (maximum deviation 0.0198 (11) Å at atom C8) is inclined at angles of 33.10 (5) and 79.57 (5)° with respect to the fluorophenyl (maximum deviation 0.0090 (12) at atom C2) and phenylthiol (maximum deviation 0.0229 (3) at atom S1) rings attached to it. The bond lengths (Allen et al., 1987) and angles are within normal ranges and comparable to the closely related structures (Shahani et al., 2009; 2010a,b).
In the crystal packing (Fig. 3), intermolecular C2—H2A···F1 hydrogen bonds (Table 1) link the neighbouring molecules into dimers, generating R22(8) ring motifs (Bernstein et al., 1995). These dimers are further linked into two-dimensional arrays parallel to the bc plane by intermolecular N2—H1N2···O1, C2—H2A···F1, C4—H4A···F1 and C5—H5A···O1 hydrogen bonds (Table 1). Weak π–π interactions were observed [Cg2···Cg2 = 3.6921 (7) Å, symmetry code = –X, –Y, 1-Z], Cg2 is the centroid of the benzene ring (C1–C6). The crystal structure is further stabilized by C—H···π interactions (Table 1), involving the C10–C15 (centroid Cg 1) and N1/N2/C7/C8/C9 rings (centroid Cg3).
For pyrazole derivatives and their microbial activity, see: Ragavan et al. (2009, 2010). For related structures, see: Shahani et al. (2009, 2010a,b,c). For hydrogen-bond motifs, see: Bernstein et al. (1995). 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 refinement: 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).
C16H13FN2OS | F(000) = 624 |
Mr = 300.34 | Dx = 1.381 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 5911 reflections |
a = 17.2628 (3) Å | θ = 2.4–33.6° |
b = 7.28340 (1) Å | µ = 0.24 mm−1 |
c = 11.4877 (2) Å | T = 100 K |
β = 91.138 (1)° | Needle, colourless |
V = 1444.09 (4) Å3 | 0.37 × 0.17 × 0.14 mm |
Z = 4 |
Bruker SMART APEXII CCD diffractometer | 5704 independent reflections |
Radiation source: fine-focus sealed tube | 4543 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
φ and ω scans | θmax = 33.6°, θmin = 2.4° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −25→26 |
Tmin = 0.918, Tmax = 0.968 | k = −9→11 |
21517 measured reflections | l = −17→17 |
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)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.113 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0502P)2 + 0.527P] where P = (Fo2 + 2Fc2)/3 |
5704 reflections | (Δ/σ)max < 0.001 |
195 parameters | Δρmax = 0.48 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
C16H13FN2OS | V = 1444.09 (4) Å3 |
Mr = 300.34 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 17.2628 (3) Å | µ = 0.24 mm−1 |
b = 7.28340 (1) Å | T = 100 K |
c = 11.4877 (2) Å | 0.37 × 0.17 × 0.14 mm |
β = 91.138 (1)° |
Bruker SMART APEXII CCD diffractometer | 5704 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 4543 reflections with I > 2σ(I) |
Tmin = 0.918, Tmax = 0.968 | Rint = 0.037 |
21517 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.113 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.48 e Å−3 |
5704 reflections | Δρmin = −0.28 e Å−3 |
195 parameters |
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems 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 | ||
S1 | 0.287633 (16) | 0.50655 (4) | 0.76602 (2) | 0.01812 (7) | |
F1 | 0.01268 (6) | −0.41073 (14) | 0.38015 (8) | 0.0433 (3) | |
O1 | 0.17691 (5) | 0.14246 (12) | 0.74551 (7) | 0.02106 (17) | |
N1 | 0.17513 (6) | 0.18952 (13) | 0.54527 (8) | 0.01725 (18) | |
N2 | 0.20721 (6) | 0.31449 (14) | 0.46958 (8) | 0.01727 (18) | |
C1 | 0.13682 (7) | −0.12951 (16) | 0.56378 (10) | 0.0193 (2) | |
H1A | 0.1672 | −0.1386 | 0.6313 | 0.023* | |
C2 | 0.09597 (7) | −0.28107 (18) | 0.52250 (11) | 0.0231 (2) | |
H2A | 0.0978 | −0.3924 | 0.5621 | 0.028* | |
C3 | 0.05246 (8) | −0.2620 (2) | 0.42099 (11) | 0.0271 (3) | |
C4 | 0.04640 (7) | −0.1000 (2) | 0.36073 (10) | 0.0285 (3) | |
H4A | 0.0161 | −0.0924 | 0.2930 | 0.034* | |
C5 | 0.08635 (7) | 0.05268 (19) | 0.40275 (10) | 0.0226 (2) | |
H5A | 0.0826 | 0.1646 | 0.3641 | 0.027* | |
C6 | 0.13208 (6) | 0.03598 (16) | 0.50366 (9) | 0.0166 (2) | |
C7 | 0.24940 (6) | 0.43573 (15) | 0.53067 (9) | 0.01692 (19) | |
C8 | 0.24443 (6) | 0.39363 (15) | 0.64842 (9) | 0.01656 (19) | |
C9 | 0.19702 (6) | 0.23394 (15) | 0.65843 (9) | 0.01662 (19) | |
C10 | 0.36501 (6) | 0.35655 (15) | 0.80605 (9) | 0.01676 (19) | |
C11 | 0.39018 (7) | 0.21470 (17) | 0.73533 (10) | 0.0211 (2) | |
H11A | 0.3652 | 0.1923 | 0.6643 | 0.025* | |
C12 | 0.45278 (7) | 0.10600 (18) | 0.77057 (11) | 0.0238 (2) | |
H12A | 0.4694 | 0.0114 | 0.7228 | 0.029* | |
C13 | 0.49050 (7) | 0.13786 (18) | 0.87642 (11) | 0.0231 (2) | |
H13A | 0.5329 | 0.0666 | 0.8991 | 0.028* | |
C14 | 0.46437 (7) | 0.27724 (17) | 0.94827 (10) | 0.0220 (2) | |
H14A | 0.4890 | 0.2980 | 1.0198 | 0.026* | |
C15 | 0.40165 (7) | 0.38605 (17) | 0.91402 (10) | 0.0199 (2) | |
H15A | 0.3842 | 0.4783 | 0.9629 | 0.024* | |
C16 | 0.29242 (7) | 0.58417 (17) | 0.47078 (10) | 0.0228 (2) | |
H16A | 0.2592 | 0.6404 | 0.4130 | 0.034* | |
H16B | 0.3370 | 0.5331 | 0.4340 | 0.034* | |
H16C | 0.3088 | 0.6748 | 0.5267 | 0.034* | |
H1N2 | 0.1992 (11) | 0.314 (3) | 0.3895 (18) | 0.049 (6)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.02393 (14) | 0.01636 (13) | 0.01404 (12) | 0.00137 (10) | −0.00028 (9) | −0.00369 (9) |
F1 | 0.0523 (6) | 0.0484 (6) | 0.0292 (4) | −0.0311 (5) | −0.0029 (4) | −0.0083 (4) |
O1 | 0.0323 (4) | 0.0221 (4) | 0.0089 (3) | −0.0046 (3) | 0.0013 (3) | 0.0002 (3) |
N1 | 0.0241 (4) | 0.0185 (4) | 0.0092 (4) | −0.0017 (3) | 0.0003 (3) | 0.0006 (3) |
N2 | 0.0237 (4) | 0.0192 (4) | 0.0090 (4) | 0.0002 (3) | 0.0013 (3) | 0.0012 (3) |
C1 | 0.0193 (5) | 0.0206 (5) | 0.0179 (5) | 0.0009 (4) | −0.0019 (4) | −0.0015 (4) |
C2 | 0.0234 (5) | 0.0226 (5) | 0.0232 (5) | −0.0027 (4) | 0.0001 (4) | −0.0022 (4) |
C3 | 0.0268 (6) | 0.0346 (7) | 0.0200 (5) | −0.0133 (5) | 0.0019 (4) | −0.0074 (5) |
C4 | 0.0260 (6) | 0.0451 (8) | 0.0143 (5) | −0.0124 (5) | −0.0026 (4) | 0.0009 (5) |
C5 | 0.0215 (5) | 0.0331 (6) | 0.0132 (5) | −0.0032 (5) | −0.0020 (4) | 0.0028 (4) |
C6 | 0.0168 (4) | 0.0212 (5) | 0.0118 (4) | 0.0002 (4) | 0.0007 (3) | −0.0026 (4) |
C7 | 0.0212 (5) | 0.0166 (5) | 0.0130 (4) | 0.0022 (4) | 0.0018 (3) | 0.0002 (4) |
C8 | 0.0221 (5) | 0.0163 (5) | 0.0114 (4) | 0.0009 (4) | 0.0009 (3) | −0.0011 (4) |
C9 | 0.0225 (5) | 0.0182 (5) | 0.0092 (4) | 0.0009 (4) | −0.0002 (3) | −0.0015 (3) |
C10 | 0.0198 (5) | 0.0173 (5) | 0.0131 (4) | −0.0018 (4) | 0.0015 (3) | 0.0000 (4) |
C11 | 0.0246 (5) | 0.0244 (5) | 0.0144 (5) | 0.0027 (4) | 0.0011 (4) | −0.0037 (4) |
C12 | 0.0273 (6) | 0.0255 (6) | 0.0189 (5) | 0.0056 (5) | 0.0037 (4) | −0.0023 (4) |
C13 | 0.0227 (5) | 0.0271 (6) | 0.0196 (5) | 0.0021 (4) | 0.0018 (4) | 0.0051 (4) |
C14 | 0.0245 (5) | 0.0257 (6) | 0.0158 (5) | −0.0033 (4) | −0.0015 (4) | 0.0031 (4) |
C15 | 0.0252 (5) | 0.0210 (5) | 0.0134 (4) | −0.0027 (4) | 0.0008 (4) | −0.0013 (4) |
C16 | 0.0295 (6) | 0.0205 (5) | 0.0186 (5) | −0.0013 (4) | 0.0052 (4) | 0.0030 (4) |
S1—C8 | 1.7371 (11) | C5—H5A | 0.9300 |
S1—C10 | 1.7790 (11) | C7—C8 | 1.3913 (15) |
F1—C3 | 1.3613 (15) | C7—C16 | 1.4879 (17) |
O1—C9 | 1.2567 (13) | C8—C9 | 1.4280 (16) |
N1—N2 | 1.3821 (13) | C10—C11 | 1.3894 (16) |
N1—C9 | 1.3848 (13) | C10—C15 | 1.3977 (15) |
N1—C6 | 1.4203 (14) | C11—C12 | 1.3933 (17) |
N2—C7 | 1.3351 (14) | C11—H11A | 0.9300 |
N2—H1N2 | 0.93 (2) | C12—C13 | 1.3873 (17) |
C1—C2 | 1.3884 (16) | C12—H12A | 0.9300 |
C1—C6 | 1.3908 (16) | C13—C14 | 1.3893 (18) |
C1—H1A | 0.9300 | C13—H13A | 0.9300 |
C2—C3 | 1.3814 (17) | C14—C15 | 1.3922 (17) |
C2—H2A | 0.9300 | C14—H14A | 0.9300 |
C3—C4 | 1.371 (2) | C15—H15A | 0.9300 |
C4—C5 | 1.3898 (18) | C16—H16A | 0.9600 |
C4—H4A | 0.9300 | C16—H16B | 0.9600 |
C5—C6 | 1.3948 (15) | C16—H16C | 0.9600 |
C8—S1—C10 | 102.64 (5) | C7—C8—S1 | 128.16 (9) |
N2—N1—C9 | 109.36 (9) | C9—C8—S1 | 124.12 (8) |
N2—N1—C6 | 121.35 (8) | O1—C9—N1 | 123.29 (10) |
C9—N1—C6 | 129.13 (9) | O1—C9—C8 | 131.59 (10) |
C7—N2—N1 | 109.03 (9) | N1—C9—C8 | 105.12 (9) |
C7—N2—H1N2 | 126.2 (13) | C11—C10—C15 | 119.47 (11) |
N1—N2—H1N2 | 124.7 (13) | C11—C10—S1 | 123.19 (8) |
C2—C1—C6 | 119.67 (10) | C15—C10—S1 | 117.34 (9) |
C2—C1—H1A | 120.2 | C10—C11—C12 | 120.16 (10) |
C6—C1—H1A | 120.2 | C10—C11—H11A | 119.9 |
C3—C2—C1 | 118.17 (12) | C12—C11—H11A | 119.9 |
C3—C2—H2A | 120.9 | C13—C12—C11 | 120.50 (11) |
C1—C2—H2A | 120.9 | C13—C12—H12A | 119.8 |
F1—C3—C4 | 118.56 (11) | C11—C12—H12A | 119.8 |
F1—C3—C2 | 118.22 (13) | C12—C13—C14 | 119.39 (11) |
C4—C3—C2 | 123.22 (12) | C12—C13—H13A | 120.3 |
C3—C4—C5 | 118.73 (11) | C14—C13—H13A | 120.3 |
C3—C4—H4A | 120.6 | C13—C14—C15 | 120.52 (10) |
C5—C4—H4A | 120.6 | C13—C14—H14A | 119.7 |
C4—C5—C6 | 119.19 (12) | C15—C14—H14A | 119.7 |
C4—C5—H5A | 120.4 | C14—C15—C10 | 119.94 (11) |
C6—C5—H5A | 120.4 | C14—C15—H15A | 120.0 |
C1—C6—C5 | 121.00 (11) | C10—C15—H15A | 120.0 |
C1—C6—N1 | 119.34 (9) | C7—C16—H16A | 109.5 |
C5—C6—N1 | 119.66 (11) | C7—C16—H16B | 109.5 |
N2—C7—C8 | 108.77 (10) | H16A—C16—H16B | 109.5 |
N2—C7—C16 | 120.64 (10) | C7—C16—H16C | 109.5 |
C8—C7—C16 | 130.59 (10) | H16A—C16—H16C | 109.5 |
C7—C8—C9 | 107.72 (9) | H16B—C16—H16C | 109.5 |
C9—N1—N2—C7 | 0.64 (12) | C16—C7—C8—S1 | 0.70 (19) |
C6—N1—N2—C7 | −175.10 (10) | C10—S1—C8—C7 | −104.41 (11) |
C6—C1—C2—C3 | 0.90 (18) | C10—S1—C8—C9 | 74.55 (10) |
C1—C2—C3—F1 | 179.69 (12) | N2—N1—C9—O1 | −179.24 (10) |
C1—C2—C3—C4 | −1.5 (2) | C6—N1—C9—O1 | −3.94 (18) |
F1—C3—C4—C5 | 179.41 (12) | N2—N1—C9—C8 | 0.04 (12) |
C2—C3—C4—C5 | 0.6 (2) | C6—N1—C9—C8 | 175.35 (11) |
C3—C4—C5—C6 | 0.9 (2) | C7—C8—C9—O1 | 178.53 (12) |
C2—C1—C6—C5 | 0.50 (18) | S1—C8—C9—O1 | −0.61 (19) |
C2—C1—C6—N1 | −178.88 (11) | C7—C8—C9—N1 | −0.68 (12) |
C4—C5—C6—C1 | −1.40 (18) | S1—C8—C9—N1 | −179.82 (8) |
C4—C5—C6—N1 | 177.98 (11) | C8—S1—C10—C11 | 14.04 (11) |
N2—N1—C6—C1 | 144.74 (11) | C8—S1—C10—C15 | −166.31 (9) |
C9—N1—C6—C1 | −30.08 (17) | C15—C10—C11—C12 | −1.69 (18) |
N2—N1—C6—C5 | −34.65 (16) | S1—C10—C11—C12 | 177.96 (10) |
C9—N1—C6—C5 | 150.54 (12) | C10—C11—C12—C13 | 0.10 (19) |
N1—N2—C7—C8 | −1.07 (12) | C11—C12—C13—C14 | 1.21 (19) |
N1—N2—C7—C16 | 178.48 (10) | C12—C13—C14—C15 | −0.93 (19) |
N2—C7—C8—C9 | 1.09 (13) | C13—C14—C15—C10 | −0.66 (18) |
C16—C7—C8—C9 | −178.40 (11) | C11—C10—C15—C14 | 1.97 (17) |
N2—C7—C8—S1 | −179.82 (9) | S1—C10—C15—C14 | −177.70 (9) |
Cg1 and Cg3 are the centroids of the pyrazol (N1/N2/C7–C9) and benzene ring (C10–C15) rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H1N2···O1i | 0.93 (2) | 1.72 (2) | 2.6352 (12) | 168 (2) |
C2—H2A···F1ii | 0.93 | 2.49 | 3.1450 (16) | 128 |
C4—H4A···F1iii | 0.93 | 2.43 | 3.2381 (15) | 145 |
C5—H5A···O1i | 0.93 | 2.56 | 3.2786 (15) | 134 |
C2—H2A···Cg1iv | 0.93 | 2.94 | 3.6300 (14) | 132 |
C12—H12A···Cg3v | 0.93 | 2.74 | 3.5928 (14) | 153 |
C16—H16B···Cg3vi | 0.96 | 2.79 | 3.6826 (13) | 155 |
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x, −y−1, −z+1; (iii) −x, y+1/2, −z+1/2; (iv) x, y−1, z; (v) −x+1, y−1/2, −z+3/2; (vi) x, −y−1/2, z−3/2. |
Experimental details
Crystal data | |
Chemical formula | C16H13FN2OS |
Mr | 300.34 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 17.2628 (3), 7.28340 (1), 11.4877 (2) |
β (°) | 91.138 (1) |
V (Å3) | 1444.09 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.24 |
Crystal size (mm) | 0.37 × 0.17 × 0.14 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.918, 0.968 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 21517, 5704, 4543 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.779 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.113, 1.03 |
No. of reflections | 5704 |
No. of parameters | 195 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.48, −0.28 |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
Cg1 and Cg3 are the centroids of the pyrazol (N1/N2/C7–C9) and benzene ring (C10–C15) rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H1N2···O1i | 0.93 (2) | 1.72 (2) | 2.6352 (12) | 168 (2) |
C2—H2A···F1ii | 0.93 | 2.49 | 3.1450 (16) | 128 |
C4—H4A···F1iii | 0.93 | 2.43 | 3.2381 (15) | 145 |
C5—H5A···O1i | 0.93 | 2.56 | 3.2786 (15) | 134 |
C2—H2A···Cg1iv | 0.93 | 2.94 | 3.6300 (14) | 132 |
C12—H12A···Cg3v | 0.93 | 2.74 | 3.5928 (14) | 153 |
C16—H16B···Cg3vi | 0.96 | 2.79 | 3.6826 (13) | 155 |
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x, −y−1, −z+1; (iii) −x, y+1/2, −z+1/2; (iv) x, y−1, z; (v) −x+1, y−1/2, −z+3/2; (vi) x, −y−1/2, z−3/2. |
Antibacterial and antifungal activities of the azoles are most widely studied and some of them are in clinical practice as anti-microbial agents. However, the azole-resistant strain had led to the development of new antimicrobial compounds. In particular pyrazole derivatives are extensively studied and used as antimicrobial agents. Pyrazole is an important class of heterocyclic compounds and many pyrazole derivatives are reported to have the broad spectrum of biological properties, such as anti-inflammatory, antifungal, herbicidal, anti-tumour, cytotoxic, molecular modelling, and antiviral activities. Pyrazole derivatives also act as antiangiogenic agents, A3 adenosine receptor antagonists, neuropeptide YY5 receptor antagonists, kinase inhibitor for treatment of type 2 diabetes, hyperlipidemia, obesity, and thrombopiotinmimetics. Recently urea derivatives of pyrazoles have been reported as potent inhibitors of p38 kinase. Since the high electronegativity of halogens (particularly chlorine and fluorine) in the aromatic part of the drug molecules play an important role in enhancing their biological activity, we are interested to have 4-fluoro or 4-chloro substitution in the aryls of 1,5-diaryl pyrazoles. As part of our on-going research aiming the synthesis of new antimicrobial compounds, we have reported the synthesis of novel pyrazole derivatives and their microbial activities (Ragavan et al., 2009; 2010). The structure of the title compound is presented here. The synthesis lead to the enol form of the compound (see Ragavan et al., 2009). However the single crystal structure determination gives the keto form. Therefore the compound undergoes an enol-to-keto tautomerism during crystallization. The interconversion of the two forms involves the movement of a proton and the shifting of bonding electrons; hence, the isomerism qualifies as tautomerism (Fig. 2)
The asymmetric unit of the title compound, (Fig. 1), consists of three rings, namely fluorophenyl (F1/C1–C6), 5-3methyl-2,5dihydro-1H-pyrazol-3-one (N1/N2/C7–C9/O1/C16) and phenylthiol (S1/C10–C15).The 1-(4-fluorophenyl)-3-methyl-4-(phenylthio)-1H-pyrazol-5-ol undergoes an enol-to-ketotautomerism during the crystallization process (Fig. 2). The 1H-pyrazole-5-one ring (maximum deviation 0.0198 (11) Å at atom C8) is inclined at angles of 33.10 (5) and 79.57 (5)° with respect to the fluorophenyl (maximum deviation 0.0090 (12) at atom C2) and phenylthiol (maximum deviation 0.0229 (3) at atom S1) rings attached to it. The bond lengths (Allen et al., 1987) and angles are within normal ranges and comparable to the closely related structures (Shahani et al., 2009; 2010a,b).
In the crystal packing (Fig. 3), intermolecular C2—H2A···F1 hydrogen bonds (Table 1) link the neighbouring molecules into dimers, generating R22(8) ring motifs (Bernstein et al., 1995). These dimers are further linked into two-dimensional arrays parallel to the bc plane by intermolecular N2—H1N2···O1, C2—H2A···F1, C4—H4A···F1 and C5—H5A···O1 hydrogen bonds (Table 1). Weak π–π interactions were observed [Cg2···Cg2 = 3.6921 (7) Å, symmetry code = –X, –Y, 1-Z], Cg2 is the centroid of the benzene ring (C1–C6). The crystal structure is further stabilized by C—H···π interactions (Table 1), involving the C10–C15 (centroid Cg 1) and N1/N2/C7/C8/C9 rings (centroid Cg3).