5-Hydr­oxy-2-methyl-4H-pyran-4-one

Abstract

The title compound, C₆H₆O₃, is a member of the pyrone family. The mol­ecules are planar (r.m.s. deviation of the asymmetric unit is 0.0248 Å, whereas that of the dimer is 0.0360 Å) and they are dimerized due to inter­molecular O—H⋯O hydrogen bonds. The dimers are connected to each other through hydrogen bonds involving the CH₃ group and the hydr­oxy O atom. There are π–π inter­actions between the centroids of the pyrone rings at a distance of 3.8552 (13) Å. A C—H⋯π inter­action also exists between the carbonyl group and the centroid CgA of the pyrone ring, with O⋯CgA = 3.65 (1) Å and C⋯CgA = 4.363 (2) Å.

Related literature

For general background, see: Aytemir et al. (1999 ▶); Erol & Yulug (1999 ▶). For studies involving metal complexes of allomaltol, see: Ma et al. (2004 ▶); Shaheen et al. (2008 ▶, 2008a ▶). For crystal structures of related compounds, see: Tak et al. (1994 ▶); Rahman et al. (1997 ▶).

Experimental

Crystal data

• C₆H₆O₃

• M _r = 126.11

• Triclinic,

• a = 5.4467 (4) Å

• b = 7.3301 (5) Å

• c = 7.6945 (5) Å

• α = 105.354 (3)°

• β = 98.416 (4)°

• γ = 100.008 (4)°

• V = 285.68 (4) ų

• Z = 2

• Mo Kα radiation

• μ = 0.12 mm⁻¹

• T = 296 (2) K

• 0.22 × 0.20 × 0.10 mm

Data collection

• Bruker Kappa APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.970, T _max = 0.986

• 6426 measured reflections

• 1504 independent reflections

• 713 reflections with I > 2σ(I)

• R _int = 0.045

Refinement

• R[F ² > 2σ(F ²)] = 0.053

• wR(F ²) = 0.131

• S = 1.00

• 1504 reflections

• 87 parameters

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

• Δρ_max = 0.18 e Å⁻³

• Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2007 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2003 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

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
O2—H2⋯O3	0.87 (3)	2.46 (2)	2.7853 (19)	103.1 (18)
O2—H2⋯O3i	0.87 (3)	1.83 (3)	2.635 (2)	152 (2)
C6—H6A⋯O2ii	0.96	2.42	3.378 (3)	173

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

supplementary crystallographic information

Comment

A variety of compounds with a 4(1H)-pyridinone structure have been synthesized and their biological activities studied extensively (Aytemir et al., 1999; Erol & Yulug, 1999). Allomaltol, the title compound (I), (Fig. 1) and its derivatives have been exploited as iron chelators (Ma et al., 2004). Ruthenium and osmium complexes of allomaltol were found to be effective in catalyzing the hydration of chloroacetonitriles (Shaheen et al., 2008, 2008a).

The crystal structures of 3-Hydroxy-4-pyrone (Tak et al., 1994) has been published which have same heterocyclic ring as of title compound. 3-Hydroxy-2-methyl-4H-pyran-4-one (Rahman et al., 1997) has also been published which is chemical isomer of (I) but have different position of CH₃. The title compound has been prepared for various purposes such as complexation and as an intermediate ligand.

The heterocyclic ring is not regular as it has two C—C [1.426 (3), 1.446 (3) Å], two C═C [1.323 (3), 1.334 (3) Å] and two C—O [1.352 (3), 1.358 (3) Å], bonds respectively. Due to intra as well as intermolecular H-bonds (Table 1), the molecules are dimerized with central four-membered [O···H···O···H] ring, (Fig. 2). The dimers are linked to each other through H-bond between CH₃ and hydroxy groups. The molecules may be stabilized due to π–π interaction between the centroids of the ring A (O1/C1–C5). The distance between the centroids of CgA and CgAⁱ [Symmetry code: i = -x, 1 - y, 1 - z] is 3.8552 (13) Å. There exist a C3═O3···π interaction (Table 1), as well.

Experimental

A mixture of 2-chloromethyl-5-hydroxy-4-pyron (1.0 g, 0.6 mmol) and zinc dust (0.8 g, 12 mmol) in water (20 ml) was stirred for 30 min at 323 K. Concentrated HCl (6 ml) was added dropwise to dissolve the zinc dust completely and the mixture was stirred for 3 h at 353 K. The reaction mixture was transferred to ice–water and extracted with dichloromethane, dried with anhydrous Na₂SO₄ and evaporated to dryness. The crystals of the title compound were obtained by recrystallizing the crude product in isopropanol.

Refinement

The coordinates of H atom of hydroxy group were refined. H atoms were positioned geometrically, with C—H = 0.93 and 0.96 Å for aromatic and methyl H, and constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C, O), where x = 1.5 for methyl H, and x = 1.2 for other H atoms.

Figures

Fig. 1.

ORTEP drawing of the title compound, with the atom numbering scheme. The thermal ellipsoids are drawn at the 30% probability level. H atoms are shown by small circles of arbitrary radii.

Fig. 2.

The packing figure (PLATON: Spek, 2003) which shows that the title compound is dimersed and dimers are connected through H-bonds in helical way.

Crystal data

C6H6O3	Z = 2
Mr = 126.11	F(000) = 132
Triclinic, P1	Dx = 1.466 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.4467 (4) Å	Cell parameters from 1504 reflections
b = 7.3301 (5) Å	θ = 2.8–29.1°
c = 7.6945 (5) Å	µ = 0.12 mm−1
α = 105.354 (3)°	T = 296 K
β = 98.416 (4)°	Prismatic, colourless
γ = 100.008 (4)°	0.22 × 0.20 × 0.10 mm
V = 285.68 (4) Å3

Data collection

Bruker Kappa APEXII CCD diffractometer	1504 independent reflections
Radiation source: fine-focus sealed tube	713 reflections with I > 2σ(I)
graphite	Rint = 0.045
Detector resolution: 7.40 pixels mm-1	θmax = 29.1°, θmin = 2.8°
ω scans	h = −7→7
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −9→9
Tmin = 0.970, Tmax = 0.986	l = −10→10
6426 measured reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.053	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.131	w = 1/[σ2(Fo2) + (0.0523P)2 + 0.0219P] where P = (Fo2 + 2Fc2)/3
S = 1.00	(Δ/σ)max < 0.001
1504 reflections	Δρmax = 0.18 e Å−3
87 parameters	Δρmin = −0.20 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.053 (14)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.2557 (3)	0.3634 (2)	0.37275 (16)	0.0542 (5)
O2	−0.1534 (3)	0.1916 (2)	0.64758 (18)	0.0641 (6)
O3	−0.4440 (3)	0.0215 (2)	0.29282 (18)	0.0631 (6)
C1	0.1595 (4)	0.3242 (3)	0.5153 (3)	0.0554 (8)
C2	−0.0705 (4)	0.2171 (3)	0.4961 (3)	0.0467 (7)
C3	−0.2315 (4)	0.1292 (3)	0.3153 (3)	0.0455 (7)
C4	−0.1223 (4)	0.1770 (3)	0.1711 (3)	0.0486 (7)
C5	0.1096 (4)	0.2896 (3)	0.2016 (3)	0.0463 (7)
C6	0.2424 (4)	0.3492 (4)	0.0642 (3)	0.0624 (8)
H1	0.26084	0.37532	0.63280	0.0664*
H2	−0.299 (5)	0.111 (4)	0.628 (3)	0.0769*
H4	−0.21633	0.12780	0.05123	0.0584*
H6A	0.13508	0.29403	−0.05590	0.0936*
H6B	0.28060	0.48817	0.09427	0.0936*
H6C	0.39779	0.30418	0.06523	0.0936*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0501 (9)	0.0655 (10)	0.0377 (8)	−0.0005 (7)	−0.0002 (6)	0.0131 (7)
O2	0.0703 (11)	0.0723 (12)	0.0356 (8)	−0.0115 (9)	0.0030 (7)	0.0143 (8)
O3	0.0506 (10)	0.0853 (12)	0.0440 (8)	−0.0041 (9)	0.0051 (7)	0.0182 (8)
C1	0.0612 (15)	0.0605 (15)	0.0346 (10)	0.0001 (12)	−0.0004 (10)	0.0117 (10)
C2	0.0540 (14)	0.0473 (13)	0.0343 (10)	0.0071 (11)	0.0035 (9)	0.0101 (9)
C3	0.0410 (13)	0.0519 (14)	0.0391 (11)	0.0078 (11)	0.0038 (9)	0.0099 (9)
C4	0.0457 (13)	0.0612 (15)	0.0327 (9)	0.0077 (11)	0.0027 (9)	0.0089 (10)
C5	0.0454 (13)	0.0544 (14)	0.0343 (10)	0.0090 (11)	0.0033 (9)	0.0091 (9)
C6	0.0547 (14)	0.0819 (17)	0.0488 (12)	0.0074 (12)	0.0110 (10)	0.0210 (12)

Geometric parameters (Å, °)

O1—C1	1.358 (3)	C4—C5	1.334 (3)
O1—C5	1.352 (3)	C5—C6	1.480 (3)
O2—C2	1.356 (3)	C1—H1	0.9300
O3—C3	1.243 (3)	C4—H4	0.9300
O2—H2	0.87 (3)	C6—H6A	0.9600
C1—C2	1.323 (3)	C6—H6B	0.9600
C2—C3	1.446 (3)	C6—H6C	0.9600
C3—C4	1.426 (3)
O1···O3i	3.200 (2)	C2···O1iii	3.350 (3)
O1···O1ii	3.078 (2)	C2···O2vi	3.405 (3)
O1···C2iii	3.350 (3)	C2···C1iii	3.501 (3)
O2···O3	2.7853 (19)	C2···C2vi	3.415 (3)
O2···C6iv	3.378 (3)	C6···O2ix	3.378 (3)
O2···O3v	2.635 (2)	C3···H2v	3.00 (3)
O2···C2vi	3.405 (3)	C4···H6Cvii	3.0000
O3···O2v	2.635 (2)	H2···O3	2.46 (2)
O3···O1vii	3.200 (2)	H2···O3v	1.83 (3)
O3···O2	2.7853 (19)	H2···C3v	3.00 (3)
O2···H6Biii	2.9000	H4···H6A	2.4500
O2···H6Aiv	2.4200	H4···O3viii	2.8200
O3···H2	2.46 (2)	H6A···O2ix	2.4200
O3···H2v	1.83 (3)	H6A···H4	2.4500
O3···H4viii	2.8200	H6B···O2iii	2.9000
C1···C1iii	3.387 (3)	H6C···C4i	3.0000
C1···C2iii	3.501 (3)
C1—O1—C5	118.57 (18)	O1—C5—C4	121.3 (2)
C2—O2—H2	116.2 (15)	O1—C1—H1	118.00
O1—C1—C2	123.6 (2)	C2—C1—H1	118.00
O2—C2—C3	120.55 (19)	C3—C4—H4	119.00
C1—C2—C3	120.2 (2)	C5—C4—H4	119.00
O2—C2—C1	119.3 (2)	C5—C6—H6A	109.00
O3—C3—C4	124.7 (2)	C5—C6—H6B	109.00
C2—C3—C4	113.9 (2)	C5—C6—H6C	109.00
O3—C3—C2	121.4 (2)	H6A—C6—H6B	109.00
C3—C4—C5	122.5 (2)	H6A—C6—H6C	109.00
O1—C5—C6	111.28 (19)	H6B—C6—H6C	109.00
C4—C5—C6	127.5 (2)
C5—O1—C1—C2	0.0 (3)	C1—C2—C3—O3	177.0 (2)
C1—O1—C5—C4	−1.4 (3)	C1—C2—C3—C4	−2.6 (3)
C1—O1—C5—C6	179.1 (2)	O3—C3—C4—C5	−178.3 (2)
O1—C1—C2—O2	−177.69 (19)	C2—C3—C4—C5	1.3 (3)
O1—C1—C2—C3	2.0 (4)	C3—C4—C5—O1	0.7 (4)
O2—C2—C3—O3	−3.3 (3)	C3—C4—C5—C6	−179.9 (2)
O2—C2—C3—C4	177.2 (2)

Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+1; (iii) −x, −y+1, −z+1; (iv) x, y, z+1; (v) −x−1, −y, −z+1; (vi) −x, −y, −z+1; (vii) x−1, y, z; (viii) −x−1, −y, −z; (ix) x, y, z−1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3	0.87 (3)	2.46 (2)	2.7853 (19)	103.1 (18)
O2—H2···O3v	0.87 (3)	1.83 (3)	2.635 (2)	152 (2)
C6—H6A···O2ix	0.9600	2.4200	3.378 (3)	173.00
C3—O3···CgAvii	1.243 (3)	3.6465 (19)	4.363 (2)	117.56 (13)

Symmetry codes: (v) −x−1, −y, −z+1; (ix) x, y, z−1; (vii) x−1, y, z.