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

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2-Iso­propyl-6-methyl­pyrimidin-4(3H)-one

aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: hkfun@usm.my

(Received 16 August 2010; accepted 25 August 2010; online 28 August 2010)

The mol­ecular structure of the title compound, C8H12N2O, indicates that 2-isopropyl-6-methyl­pyrimidin-4-ol (the enol–form) undergoes an enol-to-keto tautomerism during the crystallization process. The pyrimidin-4(3H)-one group is essentially planar, with a maximum deviation of 0.081 (1) Å for the O atom. In the crystal structure, symmetry-related mol­ecules are linked into centrosymmetic dimers via pairs of inter­molecular N—H⋯O hydrogen bonds, generating R22(8) rings. These dimers are stacked along the a axis.

Related literature

For applications of pyridinium derivatives, see: Condon et al. (1993[Condon, M. E., Brady, T. E., Feist, D., Malefyt, T., Marc, P., Quakenbush, L. S., Rodaway, S. J., Shaner, D. L. & Tecle, B. (1993). Brighton Crop Protection Conference on Weeds, pp. 41-46. Alton, Hampshire, England: BCPC Publications.]); Maeno et al. (1990[Maeno, S., Miura, I., Masuda, K. & Nagata, T. (1990). Brighton Crop Protection Conference on Pests and Diseases, pp. 415-422. Alton, Hampshire, England: BCPC Publications.]); Gilchrist (1997[Gilchrist, T. L. (1997). Heterocyclic Chemistry, 3rd ed., pp. 261-276. Singapore: Addison Wesley Longman.]); Selby et al. (2002[Selby, T. P., Drumm, J. E., Coats, R. A., Coppo, F. T., Gee, S. K., Hay, J. V., Pasteris, R. J. & Stevenson, T. M. (2002). ACS Symposium Series, Vol. 800, Synthesis and Chemistry of Agrochemicals VI, pp. 74-84. Washington DC: American Chemical Society.]). For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986[Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.]).

[Scheme 1]

Experimental

Crystal data
  • C8H12N2O

  • Mr = 152.20

  • Monoclinic, P 21 /n

  • a = 4.8627 (2) Å

  • b = 22.6320 (8) Å

  • c = 7.4228 (3) Å

  • β = 96.495 (2)°

  • V = 811.66 (5) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 100 K

  • 0.74 × 0.14 × 0.07 mm

Data collection
  • Bruker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.940, Tmax = 0.994

  • 7806 measured reflections

  • 2371 independent reflections

  • 1958 reflections with I > 2σ(I)

  • Rint = 0.026

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.103

  • S = 1.06

  • 2371 reflections

  • 148 parameters

  • All H-atom parameters refined

  • Δρmax = 0.32 e Å−3

  • Δρmin = −0.20 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H1N2⋯O1i 0.937 (15) 1.844 (14) 2.7809 (11) 178.7 (10)
Symmetry code: (i) -x+2, -y, -z+2.

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Pyrimidine derivatives are very important molecules in biology and have many application in the areas of pesticide and pharmaceutical agents (Condon et al., 1993). For example, imazosulfuron, ethirmol and mepanipyrim have been commercialized as agrochemicals (Maeno et al., 1990). Pyrimidine derivatives have also been developed as antiviral agents, such as AZT, which is the most widely used anti-AIDS drug (Gilchrist, 1997). Recently, a new series of highly active herbicides of substituted azolylpyrimidines were reported (Selby et al., 2002). Keeping in view of the importance of the pyrimidine derivatives, the title compound (I) was presented.

The title molecule, (Fig. 1), exists in the keto-form although 2-isopropyl-4-hydroxy-6-methylpyrimidine (the enol-form) was used for crystallization. This indicates the compound undergoes an enol-to-keto tautomerism during the crystallization process (Fig. 3). The C2O1 bond length is 1.2497 (11) Å. The pyrimidin-4(3H)-one group is essentially planar with a maximum deviation of 0.081 (1) Å for atom O1. In the crystal structure (Fig. 2), adjacent molecules are linked via pairs of intermolecular N—H···O hydrogen bonds to form dimers, generating R22(8) rings (Bernstein et al., 1995). These dimers are stacked along the a-axis.

Related literature top

For applications of pyridinium derivatives, see: Condon et al. (1993); Maeno et al. (1990); Gilchrist (1997); Selby et al. (2002). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Experimental top

Hot methanol solution (20 ml) of 2-isopropyl-4-hydroxy-6-methylpyrimidine (46 mg, Aldrich) was warmed over a heating magnetic stirrer for 5 minutes. The resulting solution was allowed to cool slowly at room temperature. Crystals of the title compound appeared from the mother liquor after a few days.

Refinement top

All H atoms were located in a difference Fourier map and refined freely.

Structure description top

Pyrimidine derivatives are very important molecules in biology and have many application in the areas of pesticide and pharmaceutical agents (Condon et al., 1993). For example, imazosulfuron, ethirmol and mepanipyrim have been commercialized as agrochemicals (Maeno et al., 1990). Pyrimidine derivatives have also been developed as antiviral agents, such as AZT, which is the most widely used anti-AIDS drug (Gilchrist, 1997). Recently, a new series of highly active herbicides of substituted azolylpyrimidines were reported (Selby et al., 2002). Keeping in view of the importance of the pyrimidine derivatives, the title compound (I) was presented.

The title molecule, (Fig. 1), exists in the keto-form although 2-isopropyl-4-hydroxy-6-methylpyrimidine (the enol-form) was used for crystallization. This indicates the compound undergoes an enol-to-keto tautomerism during the crystallization process (Fig. 3). The C2O1 bond length is 1.2497 (11) Å. The pyrimidin-4(3H)-one group is essentially planar with a maximum deviation of 0.081 (1) Å for atom O1. In the crystal structure (Fig. 2), adjacent molecules are linked via pairs of intermolecular N—H···O hydrogen bonds to form dimers, generating R22(8) rings (Bernstein et al., 1995). These dimers are stacked along the a-axis.

For applications of pyridinium derivatives, see: Condon et al. (1993); Maeno et al. (1990); Gilchrist (1997); Selby et al. (2002). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Computing details top

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).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The crystal packing of the title compound, viewed approximately along the a-axis. Hydrogen bonds are shown as dashed lines.
[Figure 3] Fig. 3. The title compound and the tautomeric form.
2-Isopropyl-6-methylpyrimidin-4(3H)-one top
Crystal data top
C8H12N2OF(000) = 328
Mr = 152.20Dx = 1.245 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 2995 reflections
a = 4.8627 (2) Åθ = 2.9–30.0°
b = 22.6320 (8) ŵ = 0.08 mm1
c = 7.4228 (3) ÅT = 100 K
β = 96.495 (2)°Needle, colourless
V = 811.66 (5) Å30.74 × 0.14 × 0.07 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2371 independent reflections
Radiation source: fine-focus sealed tube1958 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
φ and ω scansθmax = 30.1°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 56
Tmin = 0.940, Tmax = 0.994k = 2631
7806 measured reflectionsl = 1010
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)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.103All H-atom parameters refined
S = 1.06 w = 1/[σ2(Fo2) + (0.049P)2 + 0.163P]
where P = (Fo2 + 2Fc2)/3
2371 reflections(Δ/σ)max < 0.001
148 parametersΔρmax = 0.32 e Å3
0 restraintsΔρmin = 0.20 e Å3
Crystal data top
C8H12N2OV = 811.66 (5) Å3
Mr = 152.20Z = 4
Monoclinic, P21/nMo Kα radiation
a = 4.8627 (2) ŵ = 0.08 mm1
b = 22.6320 (8) ÅT = 100 K
c = 7.4228 (3) Å0.74 × 0.14 × 0.07 mm
β = 96.495 (2)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2371 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
1958 reflections with I > 2σ(I)
Tmin = 0.940, Tmax = 0.994Rint = 0.026
7806 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.103All H-atom parameters refined
S = 1.06Δρmax = 0.32 e Å3
2371 reflectionsΔρmin = 0.20 e Å3
148 parameters
Special details top

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 s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.77782 (15)0.03007 (3)0.81600 (9)0.02023 (18)
N10.43265 (17)0.13343 (3)0.84671 (10)0.01613 (18)
N20.75959 (17)0.06091 (3)0.94759 (10)0.01473 (17)
C10.64511 (19)0.11546 (4)0.95755 (12)0.01455 (19)
C20.6596 (2)0.01885 (4)0.82081 (12)0.0158 (2)
C30.4232 (2)0.03768 (4)0.70385 (12)0.0169 (2)
C40.32239 (19)0.09370 (4)0.71759 (12)0.0156 (2)
C50.0868 (2)0.11656 (5)0.58916 (13)0.0190 (2)
C60.7737 (2)0.15603 (4)1.10544 (13)0.01614 (19)
C70.8468 (3)0.21559 (5)1.02578 (15)0.0249 (2)
C80.5752 (2)0.16347 (5)1.25028 (14)0.0222 (2)
H1N20.915 (3)0.0510 (7)1.0283 (19)0.034 (4)*
H3A0.338 (3)0.0101 (6)0.6146 (18)0.025 (3)*
H5A0.064 (3)0.1299 (6)0.655 (2)0.036 (4)*
H5B0.011 (3)0.0864 (7)0.503 (2)0.044 (4)*
H5C0.151 (3)0.1505 (6)0.5237 (19)0.034 (4)*
H6A0.946 (3)0.1369 (5)1.1613 (16)0.018 (3)*
H7A0.922 (3)0.2424 (6)1.124 (2)0.031 (3)*
H7B0.984 (3)0.2117 (6)0.9349 (19)0.031 (4)*
H7C0.681 (3)0.2348 (6)0.9648 (19)0.036 (4)*
H8A0.661 (3)0.1874 (6)1.3518 (19)0.029 (3)*
H8B0.408 (3)0.1849 (6)1.1978 (18)0.031 (4)*
H8C0.519 (3)0.1249 (6)1.2967 (19)0.032 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0210 (4)0.0159 (3)0.0229 (4)0.0031 (3)0.0012 (3)0.0032 (3)
N10.0159 (4)0.0163 (4)0.0157 (4)0.0010 (3)0.0002 (3)0.0005 (3)
N20.0146 (4)0.0143 (4)0.0150 (4)0.0008 (3)0.0005 (3)0.0004 (3)
C10.0146 (4)0.0146 (4)0.0146 (4)0.0003 (3)0.0026 (3)0.0007 (3)
C20.0159 (4)0.0161 (4)0.0156 (4)0.0005 (3)0.0028 (3)0.0007 (3)
C30.0165 (5)0.0185 (4)0.0153 (4)0.0014 (3)0.0006 (3)0.0019 (3)
C40.0143 (4)0.0185 (5)0.0142 (4)0.0005 (3)0.0019 (3)0.0018 (3)
C50.0164 (5)0.0227 (5)0.0172 (4)0.0011 (4)0.0013 (3)0.0022 (4)
C60.0157 (4)0.0151 (4)0.0168 (4)0.0011 (3)0.0015 (3)0.0009 (3)
C70.0301 (6)0.0172 (5)0.0260 (5)0.0036 (4)0.0026 (4)0.0004 (4)
C80.0202 (5)0.0268 (5)0.0193 (5)0.0016 (4)0.0012 (4)0.0061 (4)
Geometric parameters (Å, º) top
O1—C21.2497 (11)C5—H5B0.978 (16)
N1—C11.3105 (12)C5—H5C0.978 (15)
N1—C41.3777 (12)C6—C71.5297 (14)
N2—C11.3595 (12)C6—C81.5332 (14)
N2—C21.3874 (12)C6—H6A0.990 (12)
N2—H1N20.937 (15)C7—H7A0.985 (14)
C1—C61.5114 (13)C7—H7B1.004 (14)
C2—C31.4254 (13)C7—H7C0.980 (15)
C3—C41.3672 (13)C8—H8A0.982 (14)
C3—H3A0.968 (13)C8—H8B0.987 (14)
C4—C51.4972 (13)C8—H8C0.988 (15)
C5—H5A0.973 (16)
C1—N1—C4116.83 (8)H5A—C5—H5C107.8 (12)
C1—N2—C2123.08 (8)H5B—C5—H5C109.9 (12)
C1—N2—H1N2119.2 (9)C1—C6—C7110.47 (8)
C2—N2—H1N2117.7 (9)C1—C6—C8109.54 (8)
N1—C1—N2123.11 (9)C7—C6—C8111.50 (8)
N1—C1—C6119.97 (8)C1—C6—H6A107.5 (7)
N2—C1—C6116.92 (8)C7—C6—H6A108.9 (7)
O1—C2—N2120.02 (9)C8—C6—H6A108.9 (7)
O1—C2—C3126.12 (9)C6—C7—H7A109.9 (8)
N2—C2—C3113.86 (8)C6—C7—H7B112.5 (8)
C4—C3—C2120.21 (9)H7A—C7—H7B109.4 (11)
C4—C3—H3A121.2 (8)C6—C7—H7C110.8 (9)
C2—C3—H3A118.6 (8)H7A—C7—H7C106.5 (12)
C3—C4—N1122.85 (9)H7B—C7—H7C107.6 (11)
C3—C4—C5121.86 (9)C6—C8—H8A110.7 (8)
N1—C4—C5115.27 (8)C6—C8—H8B109.4 (8)
C4—C5—H5A110.6 (9)H8A—C8—H8B106.8 (12)
C4—C5—H5B112.3 (9)C6—C8—H8C111.6 (8)
H5A—C5—H5B107.2 (12)H8A—C8—H8C109.3 (11)
C4—C5—H5C108.9 (8)H8B—C8—H8C109.0 (11)
C4—N1—C1—N21.11 (13)C2—C3—C4—N12.79 (14)
C4—N1—C1—C6178.69 (8)C2—C3—C4—C5175.72 (8)
C2—N2—C1—N10.98 (14)C1—N1—C4—C30.79 (13)
C2—N2—C1—C6178.83 (8)C1—N1—C4—C5177.82 (8)
C1—N2—C2—O1178.41 (8)N1—C1—C6—C752.88 (12)
C1—N2—C2—C30.98 (12)N2—C1—C6—C7127.31 (9)
O1—C2—C3—C4176.61 (9)N1—C1—C6—C870.32 (11)
N2—C2—C3—C42.73 (13)N2—C1—C6—C8109.50 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H1N2···O1i0.937 (15)1.844 (14)2.7809 (11)178.7 (10)
Symmetry code: (i) x+2, y, z+2.

Experimental details

Crystal data
Chemical formulaC8H12N2O
Mr152.20
Crystal system, space groupMonoclinic, P21/n
Temperature (K)100
a, b, c (Å)4.8627 (2), 22.6320 (8), 7.4228 (3)
β (°) 96.495 (2)
V3)811.66 (5)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.74 × 0.14 × 0.07
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 2009)
Tmin, Tmax0.940, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections
7806, 2371, 1958
Rint0.026
(sin θ/λ)max1)0.705
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.103, 1.06
No. of reflections2371
No. of parameters148
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.32, 0.20

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H1N2···O1i0.937 (15)1.844 (14)2.7809 (11)178.7 (10)
Symmetry code: (i) x+2, y, z+2.
 

Footnotes

Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

MH and HKF thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

References

First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCondon, M. E., Brady, T. E., Feist, D., Malefyt, T., Marc, P., Quakenbush, L. S., Rodaway, S. J., Shaner, D. L. & Tecle, B. (1993). Brighton Crop Protection Conference on Weeds, pp. 41–46. Alton, Hampshire, England: BCPC Publications.  Google Scholar
First citationCosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationGilchrist, T. L. (1997). Heterocyclic Chemistry, 3rd ed., pp. 261–276. Singapore: Addison Wesley Longman.  Google Scholar
First citationMaeno, S., Miura, I., Masuda, K. & Nagata, T. (1990). Brighton Crop Protection Conference on Pests and Diseases, pp. 415–422. Alton, Hampshire, England: BCPC Publications.  Google Scholar
First citationSelby, T. P., Drumm, J. E., Coats, R. A., Coppo, F. T., Gee, S. K., Hay, J. V., Pasteris, R. J. & Stevenson, T. M. (2002). ACS Symposium Series, Vol. 800, Synthesis and Chemistry of Agrochemicals VI, pp. 74–84. Washington DC: American Chemical Society.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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