4-[Bis(3-phenyl-1H-pyrazol-1-yl)meth­yl]benzene-1,2-diol

Florian Blasberg; Hans-Wolfram Lerner; Michael Bolte

doi:10.1107/S1600536811037949

. 2011 Sep 30;67(Pt 10):o2741. doi: 10.1107/S1600536811037949

4-[Bis(3-phenyl-1H-pyrazol-1-yl)methyl]benzene-1,2-diol

Florian Blasberg ^a, Hans-Wolfram Lerner ^a, Michael Bolte ^a,^*

PMCID: PMC3201530 PMID: 22058803

Abstract

The title compound, C₂₅H₂₀N₄O₂, is a ditopic ortho-hydroquinone-based bis(pyrazol-1-yl)methane ligand. The dihedral angles between the planes of the pyrazole rings and their attached phenyl rings are 17.4 (3) and 5.9 (4)°. The pyrazole rings make a dihedral angle of 87.84 (16)°. One of the two hydroxy groups forms an intramolecular hydrogen bond to the other hydroxy group, whereas the second is involved in an intermolecular O—H⋯N hydrogen bond. As a result of these intermolecular hydrogen bonds, helical chains running along the b axis are formed.

Related literature

For the synthesis, structural characterization and coordination behavior of ditopic ortho-hydroquinone-based bis(pyrazol-1-yl)methane ligands, see: Blasberg et al. (2011 ▶).

Experimental

Crystal data

C₂₅H₂₀N₄O₂
M _r = 408.45
Monoclinic,
a = 13.493 (3) Å
b = 5.6288 (11) Å
c = 26.309 (5) Å
β = 100.87 (3)°
V = 1962.3 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 173 K
0.40 × 0.15 × 0.10 mm

Data collection

Stoe IPDS II two-circle diffractometer
16343 measured reflections
3450 independent reflections
1434 reflections with I > 2σ(I)
R _int = 0.111

Refinement

R[F ² > 2σ(F ²)] = 0.069
wR(F ²) = 0.121
S = 0.82
3450 reflections
282 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811037949/ez2261sup1.cif

e-67-o2741-sup1.cif^{(21.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811037949/ez2261Isup2.hkl

e-67-o2741-Isup2.hkl^{(169.2KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811037949/ez2261Isup3.cml

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
O23—H23⋯O24	0.84	2.21	2.646 (5)	113
O24—H24⋯N12ⁱ	0.84	2.08	2.853 (5)	153

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

Very recently we have reported on the synthesis, structural characterization, and coordination behavior of ditopic ortho-hydroquinone-based bis(pyrazol-1-yl)methane ligands (Blasberg et al., 2011). In this report, we have already noted ortho-(OH)₂C₆H₃-4-CH(3-Phpz)₂, but metric parameters will be discussed here. The bis(pyrazol-1-yl)methane derivative (I) was prepared in a three-step one-pot procedure as shown in Fig. 1.

The dihedral angles between the planes of the pyrazol rings and the attached phenyl rings are 20.9 (3)° and 5.9 (4)°. One of the two hydroxy groups forms an intramolecular hydrogen bond to the other hydroxy group, whereas the second one is involved in an intermolecular O—H···N hydrogen bond. As a result of these intermolecular hydrogen bonds, helical chains running along the b axis are formed.

Experimental

Neat 3-phenylpyrazole (2.00 g, 13.87 mmol) was added to NaH (0.33 g, 13.87 mmol) suspended in THF (60 ml) at r.t. After 30 min SOCl₂ (0.50 ml, 0.83 g, 6.94 mmol) was added in one portion and the resulting mixture stirred at r.t. for 5 min. After 3,4-dihydroxybenzaldehyde (0.96 g, 6.94 mmol) and pyridine (5.60 ml, 4.78 g, 60.40 mmol) were added, the reaction mixture was kept at reflux temperature for 16 h. H₂O (50 ml) was added and the aqueous phase extracted into CH₂Cl₂ (3×50 ml). The combined organic extracts were washed with brine, dried (MgSO₄), filtered, and the filtrate was evaporated to dryness in vacuo. The crude product was purified by column chromatography (silica gel; CHCl₃/EtOAc 1:1) and all product-containing fractions were concentrated by rotary evaporation at 40°C to ca. half of the original volume. Upon cooling to r.t. colorless crystals of the title compound precipitated, which were isolated by filtration and washed with Et₂O. Yield: 1.53 g (54%). Single crystals suitable for X-ray diffraction were obtained by repeatedly dissolving the compound in refluxing MeCN and letting the clear colorless solution cool to room temperature. After three cycles needles of sufficient size were obtained. R</f = 0.63 (silica gel, CHCl₃/EtOAc 1:1). ¹H NMR (400.1 MHz, d₆-DMSO) δ = 6.48 (dd, ³J_HH = 8.3, ⁴J_HH = 2.0, 1 H; HQ—H6), 6.66 (d, ⁴J_HH = 2.0, 1 H; HQ—H2), 6.76 (d, ³J_HH = 8.3, 1 H; HQ—H5), 6.84 (d, ³J_HH = 2.5, 2 H; pz-H4), 7.31 (m, 2 H; Ph—H4), 7.41 (m, 4 H; Ph—H3), 7.82 (m, 4 H; Ph—H2), 7.91 (s, 1H, CH), 7.94 (d, ³J_HH = 2.5, 2 H; pz-H5), 9.15 (bs, 2 H; OH). ¹³C NMR (100.6 MHz, d₆-DMSO) δ = 76.7 (Cpz₂), 103.5 (pz-C4), 114.4 (HQ—C2), 115.5 (HQ—C5), 118.2 (HQ—C6), 125.3 (Ph—C2), 127.2 (HQ—C1), 127.8 (Ph—C4), 128.7 (Ph—C3), 131.9 (pz-C5), 132.8 (Ph—C1), 145.3, 146.1 (HQ—C3,4), 151.0 (pz-C3). ESI-MS: m/z (%) 263 (67) [M—Phpz]^-, 408 (100) [M—H]^-. Anal. Calcd (%) for C₂₅H₂₀N₄O₂ (408.45): C 73.51, H 4.94, N 13.72. Found: C 73.22, H 4.86, N 13.67.