5-Cyclo­hexyl-4-methyl-1H-pyrazol-3(2H)-one monohydrate

Tara Shahani; Hoong-Kun Fun; R Venkat Ragavan; V Vijayakumar; S Sarveswari

doi:10.1107/S1600536810039164

. 2010 Oct 9;66(Pt 11):o2760–o2761. doi: 10.1107/S1600536810039164

5-Cyclohexyl-4-methyl-1H-pyrazol-3(2H)-one monohydrate

Tara Shahani ^a, Hoong-Kun Fun ^a,^*,^‡, R Venkat Ragavan ^b, V Vijayakumar ^b, S Sarveswari ^b

PMCID: PMC3009194 PMID: 21588963

Abstract

In the title compound, C₁₀H₁₆N₂O·H₂O, the cyclohexane ring is in a chair conformation and its least-squares plane makes a dihedral angle of 53.68 (5)° with the approximately planar pyrazole ring [maximum deviation = 0.034 (1) Å]. Pairs of intermolecular N—H⋯O hydrogen bonds form inversion dimers between neighbouring pyrazolone molecules, generating R ₂ ²(8) ring motifs. The pyrazolone and water molecules are further linked by intermolecular N—H⋯O, C—H⋯O and O—H⋯O hydrogen bonds into two-dimensional sheets parallel to the bc plane.

Related literature

For pyrazole derivatives and their microbial activities, see: Ragavan et al. (2009 ▶, 2010 ▶). For related structures, see: Shahani et al. (2009 ▶, 2010a ▶,b ▶,c ▶). For ring conformations, see: Cremer & Pople (1975 ▶). 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 for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₀H₁₆N₂O·H₂O
M _r = 198.26
Monoclinic,
a = 13.4959 (3) Å
b = 6.2497 (1) Å
c = 13.9268 (3) Å
β = 112.782 (1)°
V = 1083.02 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.46 × 0.27 × 0.23 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.962, T _max = 0.981
26403 measured reflections
4715 independent reflections
3863 reflections with I > 2σ(I)
R _int = 0.033

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.117
S = 1.03
4715 reflections
199 parameters
All H-atom parameters refined
Δρ_max = 0.55 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: 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 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810039164/is2608sup1.cif

e-66-o2760-sup1.cif^{(18KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810039164/is2608Isup2.hkl

e-66-o2760-Isup2.hkl^{(231KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N1⋯O1Wⁱ	0.889 (14)	1.866 (14)	2.7513 (9)	173.7 (12)
N2—H1N2⋯O1ⁱⁱ	0.924 (14)	1.842 (13)	2.7552 (9)	169.5 (13)
O1W—H1W1⋯O1	0.889 (17)	1.851 (17)	2.7354 (8)	173.2 (18)
O1W—H1W2⋯O1ⁱⁱⁱ	0.860 (19)	1.961 (19)	2.8007 (9)	165.0 (16)
C5—H5A⋯O1Wⁱ	0.987 (14)	2.503 (15)	3.4161 (12)	153.7 (11)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

HKF and TS thank Universiti Sains Malaysia (USM) for the Research University Grant (grant No. 1001/PFIZIK/811160). TS also thanks USM for the award of a research fellowship. VV is grateful to the DST-India for funding through the Young Scientist Scheme (Fast Track Proposal).

supplementary crystallographic information

Comment

Antibacterial and antifungal activities of the azoles are most widely studied and some of them are used in clinical practice as anti-microbial agents. However, the existence of azole-resistant strains had led to the development of new antimicrobial compounds. In particular, pyrazole derivatives are also extensively studied and used as antimicrobial agents. Pyrazole is an important class of heterocyclic compound and many pyrazole derivatives are reported to have the broad spectrum of biological activities, such as anti-inflammatory, antifungal, herbicidal, anti-tumour, cytotoxic 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 on 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 asymmetric unit of the title compound, (Fig. 1), consists of one 5-cyclohexyl-4-methyl-1H-pyrazol-3(2H)-one molecule (C1—C10/N1/N2/O1) and one water molecule. The 3-cyclohexyl-4-methyl-1 H-pyrazol-5-ol undergoes an enol-to-keto tautomerism during the crystallization process (Fig. 2). The cyclohexane ring is in a chair conformation with puckering parameters of Q = 0.5813 (10) Å, Θ = 177.06 (10)° and φ = 164.9 (19)° (Cremer & Pople, 1975), and its least-squares plane is at an angle of 53.68 (5)° with the approximately planar pyrazole ring (C7–C9/N1/N2; maximum deviation of 0.034 (1) Å at atom N2). The bond lengths (Allen et al., 1987) and angles are within normal ranges and comparable to those closely related structures (Shahani et al., 2009, 2010a,b,c)

In the crystal packing (Fig. 3), pairs of intermolecular N2—H1N2···O1 hydrogen bonds (Table 1) form dimers with neighbouring molecules, generating R₂²(8) ring motifs (Bernstein et al., 1995). The molecules are further linked by intermolecular N1—H1N1···O1W, C5—H5A···O1W, O1W—H1W1···O1 and O1W—H1W2 ···O1 hydrogen bonds (Table 1) into two-dimensional sheets parallel to the bc plane.

Experimental

The compound has been synthesized using the method available in the literature (Ragavan et al., 2010) and recrystallized using the ethanol-chloroform 1:1 mixture. Yield: 77%. m.p.: 205.4–206.2 °C.