organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

5-tert-But­yl-4-bromo-1,2-di­hydro-1H-pyrazol-3(2H)-one monohydrate

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aSchool of Science and the Environment, Coventry University, Coventry CV1 5FB, England, and bKey Organics Ltd, Highfield Industrial Estate, Camelford, Cornwall PL32 9QZ, England
*Correspondence e-mail: apx106@coventry.ac.uk

(Received 21 April 2005; accepted 22 April 2005; online 6 July 2005)

The structure of the title compound, C7H11BrN2O·H2O, exhibits an elaborate hydrogen-bonding network involving pyrazole N—H⋯O dimers and two other hydrogen-bonding motifs, both including water mol­ecules. One motif is a distorted hexa­gonal R35(11) graph set, while the other is a distorted octa­gonal boat conformation R64(14) graph set.

Comment

In a series of studies on the preparation and hydrogen-bonding properties of 3,4,5-tri-substituted pyrazoles, we recently characterized the structure of 5-tert-but­yl-4-nitro-1H-pyrazol-3-ol (Lynch & McClenaghan, 2005[Lynch, D. E. & McClenaghan, I. (2005). Acta Cryst. E61, o2347-o2348.]). We report here the structure of the title compound, (I)[link]. Similar to 5-tert-but­yl-4-nitro-1H-pyrazol-3-ol, compound (I)[link] originated from 3,5-di-tert-butyl­pyrazole. Compound (I)[link] was prepared by reacting 3,5-di-tert-butyl­pyrazole with bromine in chloro­form solution at room temperature. In these reactions, 3,5-di-t-butyl­pyrazole is attacked by either nitric acid (as in the case of 5-tert-but­yl-4-nitro-1H-pyrazol-3-ol) or bromine to form the onium species, which then displaces one tert-but­yl group. The subsequent vacant position is then filled by an OH group that, in the case of (I)[link], tautomerizes to form the pyrazolone.

[Scheme 1]

In the structure of (I)[link] (Fig. 1[link]), all strong hydrogen-bonding components are involved in the hydrogen-bonding network. The hydrogen-bonding geometry for this structure is listed in Table 1[link]. The fourfold symmetry in (I)[link] arises because of the unique hydrogen-bonded motif that is formed via contributions from eight pyrazole mol­ecules and four water mol­ecules. Each pyrazole mol­ecule forms a centrosymmetric R22(8) graph set (Etter, 1990[Etter, M. C. (1990). Acc. Chem. Res. 23, 120-126.]) dimer via N1—H⋯O5 inter­actions, at (x, y, z) and (−x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]), centred at ([{3\over 4}], [1\over 4], [1\over4]). The N2/H group associates with O1W, at (x, y, z) and (y + [{1\over 4}], −x + [{5\over 4}], z + [{1\over 4}]). O1W, at (x, y, z), associates with two O5 atoms, one at (x, y, z) and the other at (−y + [{5\over 4}], x − [{3\over 4}], −z + [{1\over 4}]). Thus, each O5 atom is involved in a four-centre hydrogen-bonding association. For O5, at (x, y, z), the three non-H-atom contacts are O1W at (x, y, z), O1I at (y + [{3\over 4}], −x + [{5\over 4}], −z + [{1\over 4}]) and N1 at (−x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]) (Fig. 2[link]). Three pyrazole mol­ecules, at (x, y, z), (−x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]) and (−y + [{5\over 4}], x − [{3\over 4}], −z + [{1\over 4}]), and two water mol­ecules, at (x, y, z) and (−y + [{5\over 4}], x − [{3\over 4}], −z + [{1\over 4}]), form a distorted hexa­gonal hydrogen-bonding motif [graph set R35(11)], adjoining the N1—H⋯O5 dimer, fused via the same inter­action (Fig. 3[link]). The hexa­gonal motifs are also fused with each other via the O1W—H⋯O5 inter­action at (x, y, z). The resulting arrangement also creates a distorted octa­gonal boat conformation hydrogen-bonding motif [graph set R64(14)] involving four pyrazole groups, at (x, y, z), (−x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]), (x − [{1\over 2}], y, −z + [{1\over 2}]) and (1 − x, −y + [{1\over 2}], z), and two water mol­ecules, at (y + [{1\over 4}], −x + [{5\over 4}], z + [{1\over 4}]) and (−y + [{3\over 4}], x − [{3\over 4}], z + [{1\over 4}]) (Fig. 4[link]). A stereoview of the unit cell contents of (I)[link] is shown in Fig. 5[link]. The Br atom does not contribute to the hydrogen-bonding network; atom Br4 is 3.469 (3) Å from O1W, and 3.412 (3) Å from N2(−y + [{5\over 4}], x − [{1\over 4}], z − [{1\over 4}]).

[Figure 1]
Figure 1
Mol­ecular configuration and atom-numbering scheme for (I)[link]. Displacement ellipsoids are drawn at the 50% probability level and H atoms are drawn as spheres of arbitrary radii.
[Figure 2]
Figure 2
Hydrogen-bonding environment for (I)[link], at (x, y, z), showing the centrosymmetric R22(8) N1—H⋯O5 dimer, the two hydrogen-bonding associations from O1W, and the four-centre hydrogen-bonding association involving O5. For clarity, H atoms not involved in the hydrogen-bonding inter­actions have been omitted. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (i) −x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]; (ii) y + [{1\over 4}], −x + [{5\over 4}], z + [{1\over 4}]; (iii) −y + [{5\over 4}], x − [{3\over 4}], −z + [{1\over 4}]; (iv) y + [{3\over 4}], −x + [{5\over 4}], −z + [{1\over 4}].]
[Figure 3]
Figure 3
Part of the structure of (I)[link], at (x, y, z), showing the distorted R35(11) hexa­gonal motif, and its position with respect to the N1—H⋯O5 dimer. For clarity, H atoms not involved in the hydrogen-bonding inter­actions have been omitted. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (i) −x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]; (ii) −y + [{5\over 4}], x − [{3\over 4}], z − [{1\over 4}].]
[Figure 4]
Figure 4
Part of the structure of (I)[link], at (x, y, z), showing the distorted R64(14) octa­gonal boat motif and its position with respect to the N1—H⋯O5 dimer. For clarity, H atoms not involved in the hydrogen-bonding inter­actions have been omitted. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (i) −x + [{3\over 2}], −y + [{1\over 2}], −z + [{1\over 2}]; (ii) −y + [{3\over 4}], x − [{3\over 4}], z + [{1\over 4}]; (iii) 1 − x, −y + [{1\over 2}], z; (iv) x − [{1\over 2}], y, −z + [{1\over 2}]; (v) y + [{1\over 4}], −x + [{5\over 4}], z + [{1\over 4}].]
[Figure 5]
Figure 5
Stereoview of the unit cell contents of (I)[link].

Experimental

The title compound was obtained from Key Organics Ltd, and crystals were grown from an ethanol solution.

Crystal data
  • C7H11BrN2O·H2O

  • Mr = 237.10

  • Tetragonal, I 41 /a

  • a = 13.6840 (4) Å

  • c = 21.4734 (8) Å

  • V = 4020.9 (2) Å3

  • Z = 16

  • Dx = 1.567 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 2331 reflections

  • θ = 2.9–27.5°

  • μ = 4.06 mm−1

  • T = 150 (2) K

  • Prism, colourless

  • 0.36 × 0.27 × 0.20 mm

Data collection
  • Nonius KappaCCD diffractometer

  • φ and ω scans

  • Absorption correction: multi-scan(SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Version 2.10. Bruker AXS Inc., Madison, Wisconsin, USA.])Tmin = 0.288, Tmax = 0.444

  • 12 489 measured reflections

  • 1977 independent reflections

  • 1633 reflections with I > 2σ(I)

  • Rint = 0.069

  • θmax = 26.0°

  • h = −16 → 16

  • k = −15 → 14

  • l = −19 → 26

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.030

  • wR(F2) = 0.069

  • S = 1.02

  • 1977 reflections

  • 124 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • w = 1/[σ2(Fo2) + (0.0247P)2 + 7.0406P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.30 e Å−3

  • Δρmin = −0.64 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O5i 0.82 (3) 1.97 (3) 2.773 (3) 168 (3)
N2—H2⋯O1Wii 0.85 (3) 1.80 (3) 2.646 (3) 171 (3)
O1W—H1W⋯O5 0.83 (2) 1.91 (2) 2.733 (3) 169 (3)
O1W—H2W⋯O5iii 0.83 (2) 1.91 (2) 2.739 (3) 173 (3)
Symmetry codes: (i) [-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (ii) [y+{\script{1\over 4}}, -x+{\script{5\over 4}}, z+{\script{1\over 4}}]; (iii) [-y+{\script{5\over 4}}, x-{\script{3\over 4}}, -z+{\script{1\over 4}}].

All tert-but­yl H atoms were included in the refinement at calculated positions, in the riding-model approximation, with C—H distances of 0.98 Å. All NH H atoms involved in the hydrogen-bonding associations (Table 1[link]) were located in Fourier syntheses and positional parameters were refined. The water H atoms were located and were refined with O—H distance restraints of 0.83 (2) Å and H⋯H restraints of 1.40 (2) Å. The isotropic displacement parameters for all H atoms were set equal to 1.25Ueq of the carrier atom.

Data collection: COLLECT (Hooft, 1998[Hooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: PLATON97 (Spek, 1997[Spek, A. L. (1997). PLATON9. University of Utrecht, The Netherlands.]); software used to prepare material for publication: SHELXL97.

Supporting information


Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON97 (Spek, 1997); software used to prepare material for publication: SHELXL97.

5-tert-Butyl-4-bromo-1,2-dihydro-1H-pyrazol-3(2H)-one monohydrate top
Crystal data top
C7H11BrN2O·H2ODx = 1.567 Mg m3
Mr = 237.10Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I41/aCell parameters from 2331 reflections
Hall symbol: -I 4adθ = 2.9–27.5°
a = 13.6840 (4) ŵ = 4.06 mm1
c = 21.4734 (8) ÅT = 150 K
V = 4020.9 (2) Å3Prism, colourless
Z = 160.36 × 0.27 × 0.20 mm
F(000) = 1920
Data collection top
Nonius KappaCCD?
diffractometer
1977 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode1633 reflections with I > 2σ(I)
10 cm confocal mirrors monochromatorRint = 0.069
Detector resolution: 9.091 pixels mm-1θmax = 26.0°, θmin = 3.5°
φ and ω scansh = 1616
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 1514
Tmin = 0.288, Tmax = 0.444l = 1926
12489 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.069H atoms treated by a mixture of independent and constrained refinement
S = 1.02 w = 1/[σ2(Fo2) + (0.0247P)2 + 7.0406P]
where P = (Fo2 + 2Fc2)/3
1977 reflections(Δ/σ)max < 0.001
124 parametersΔρmax = 0.30 e Å3
3 restraintsΔρmin = 0.64 e Å3
Special details top

Experimental. The minimum and maximum absorption values stated above are those calculated in SHELXL97 from the given crystal dimensions. The ratio of minimum to maximum apparent transmission was determined experimentally as 0.630689.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br40.688965 (19)0.380502 (19)0.044971 (12)0.02124 (11)
O50.78480 (12)0.27537 (13)0.16996 (8)0.0182 (4)
N10.64408 (16)0.31605 (16)0.22405 (10)0.0166 (5)
H10.660 (2)0.295 (2)0.2582 (14)0.021*
N20.55701 (16)0.36121 (16)0.21224 (10)0.0170 (5)
H20.520 (2)0.374 (2)0.2427 (14)0.021*
C30.55559 (18)0.39126 (18)0.15299 (12)0.0157 (5)
C310.46896 (19)0.44595 (19)0.12557 (12)0.0181 (6)
C320.5036 (2)0.5478 (2)0.10536 (15)0.0265 (7)
H310.52580.58440.14190.033*
H320.44950.58290.08550.033*
H330.55770.54130.07570.033*
C330.4290 (2)0.3888 (2)0.06939 (13)0.0262 (6)
H340.48030.38230.03780.033*
H350.37320.42390.05160.033*
H360.40800.32370.08290.033*
C340.3868 (2)0.4572 (2)0.17367 (14)0.0267 (7)
H370.36550.39250.18770.033*
H380.33160.49170.15470.033*
H390.41090.49470.20940.033*
C40.64375 (18)0.36354 (18)0.12658 (11)0.0151 (5)
C50.70015 (19)0.31513 (18)0.17256 (12)0.0153 (5)
O1W0.86437 (18)0.19982 (16)0.06359 (9)0.0364 (6)
H1W0.833 (2)0.223 (2)0.0934 (9)0.045*
H2W0.898 (2)0.1507 (16)0.0717 (13)0.045*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br40.02379 (17)0.02565 (17)0.01427 (16)0.00435 (11)0.00409 (11)0.00462 (11)
O50.0139 (9)0.0236 (10)0.0169 (10)0.0034 (7)0.0003 (7)0.0021 (8)
N10.0178 (12)0.0201 (12)0.0120 (11)0.0017 (9)0.0013 (9)0.0039 (9)
N20.0168 (12)0.0194 (12)0.0146 (12)0.0018 (9)0.0028 (9)0.0005 (9)
C30.0191 (14)0.0131 (13)0.0150 (13)0.0019 (10)0.0010 (10)0.0017 (10)
C310.0180 (14)0.0184 (13)0.0180 (14)0.0025 (10)0.0006 (11)0.0024 (11)
C320.0234 (15)0.0232 (15)0.0330 (17)0.0022 (12)0.0005 (13)0.0043 (13)
C330.0251 (15)0.0294 (16)0.0241 (16)0.0032 (13)0.0074 (13)0.0003 (13)
C340.0207 (15)0.0312 (16)0.0283 (17)0.0069 (12)0.0014 (13)0.0048 (13)
C40.0181 (13)0.0153 (13)0.0117 (13)0.0000 (10)0.0013 (10)0.0019 (10)
C50.0185 (14)0.0120 (13)0.0154 (14)0.0031 (10)0.0000 (11)0.0012 (10)
O1W0.0584 (16)0.0321 (13)0.0186 (11)0.0256 (11)0.0121 (10)0.0073 (9)
Geometric parameters (Å, º) top
Br4—C41.873 (2)C32—H310.98
O5—C51.281 (3)C32—H320.98
N1—C51.346 (3)C32—H330.98
N1—N21.366 (3)C33—H340.98
N1—H10.82 (3)C33—H350.98
N2—C31.337 (3)C33—H360.98
N2—H20.85 (3)C34—H370.98
C3—C41.386 (4)C34—H380.98
C3—C311.521 (4)C34—H390.98
C31—C341.534 (4)C4—C51.417 (4)
C31—C321.535 (4)O1W—H1W0.83 (2)
C31—C331.538 (4)O1W—H2W0.83 (2)
C5—N1—N2110.4 (2)H32—C32—H33109.5
C5—N1—H1125 (2)C31—C33—H34109.5
N2—N1—H1124 (2)C31—C33—H35109.5
C3—N2—N1109.2 (2)H34—C33—H35109.5
C3—N2—H2131 (2)C31—C33—H36109.5
N1—N2—H2119 (2)H34—C33—H36109.5
N2—C3—C4107.0 (2)H35—C33—H36109.5
N2—C3—C31122.1 (2)C31—C34—H37109.5
C4—C3—C31130.9 (2)C31—C34—H38109.5
C3—C31—C34111.1 (2)H37—C34—H38109.5
C3—C31—C32108.4 (2)C31—C34—H39109.5
C34—C31—C32109.0 (2)H37—C34—H39109.5
C3—C31—C33109.3 (2)H38—C34—H39109.5
C34—C31—C33108.6 (2)C3—C4—C5108.5 (2)
C32—C31—C33110.5 (2)C3—C4—Br4129.53 (19)
C31—C32—H31109.5C5—C4—Br4121.99 (19)
C31—C32—H32109.5O5—C5—N1123.7 (2)
H31—C32—H32109.5O5—C5—C4131.3 (2)
C31—C32—H33109.5N1—C5—C4104.9 (2)
H31—C32—H33109.5H1W—O1W—H2W116 (3)
C5—N1—N2—C30.6 (3)C31—C3—C4—C5179.2 (3)
N1—N2—C3—C40.5 (3)N2—C3—C4—Br4178.78 (19)
N1—N2—C3—C31178.9 (2)C31—C3—C4—Br41.8 (4)
N2—C3—C31—C341.8 (4)N2—N1—C5—O5178.3 (2)
C4—C3—C31—C34178.8 (3)N2—N1—C5—C40.4 (3)
N2—C3—C31—C32117.9 (3)C3—C4—C5—O5178.5 (3)
C4—C3—C31—C3261.5 (4)Br4—C4—C5—O50.6 (4)
N2—C3—C31—C33121.6 (3)C3—C4—C5—N10.1 (3)
C4—C3—C31—C3359.0 (4)Br4—C4—C5—N1179.23 (17)
N2—C3—C4—C50.3 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O5i0.82 (3)1.97 (3)2.773 (3)168 (3)
N2—H2···O1Wii0.85 (3)1.80 (3)2.646 (3)171 (3)
O1W—H1W···O50.83 (2)1.91 (2)2.733 (3)169 (3)
O1W—H2W···O5iii0.83 (2)1.91 (2)2.739 (3)173 (3)
Symmetry codes: (i) x+3/2, y+1/2, z+1/2; (ii) y+1/4, x+5/4, z+1/4; (iii) y+5/4, x3/4, z+1/4.
 

Acknowledgements

The authors thank the EPSRC National Crystallography Service (Southampton, England).

References

First citationEtter, M. C. (1990). Acc. Chem. Res. 23, 120–126.  CrossRef CAS Web of Science Google Scholar
First citationHooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
First citationLynch, D. E. & McClenaghan, I. (2005). Acta Cryst. E61, o2347–o2348.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationSheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2003). SADABS. Version 2.10. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationSpek, A. L. (1997). PLATON9. University of Utrecht, The Netherlands.  Google Scholar

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