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Acta Cryst. (2010). E66, o397    [ doi:10.1107/S1600536810001601 ]

Ethyl 2-(3-acetyl-6-methyl-2-oxo-2H-pyran-4-yloxy)acetate

M. Rabnawaz, S. D. Benson, B. Khan and M. R. Shah

Abstract top

The title compound, C12H14O6, features a roughly planar molecule (r.m.s. deviation for all non-H atoms = 0.287 Å). In the crystal, the molecules are held together by C-H...O hydrogen bonds.

Comment top

3-Acetyl-4-hydroxy-6-methyl-2-oxo-2H-pyran (dehydroacetic acid) is a versatile starting material for the synthesis of a wide variety of heterocyclic ring systems (Prakash et al., 2004) and biologically important molecules like coumarins (Hernandez-Galan et al., 1993).

Related literature top

The title compared was prepared from dehydroacetic acid (3-acetyl-4-hydroxy-6-methyl-2-oxo-2H-pyran) treated with ethylbromoacetate in acetone in the presence of K2CO3. For the use of dehydroacetic acid as a starting material in the synthesis of heterocyclic ring systems, see: Prakash et al. (2004), and of biologically important molecules such as coumarins, see: Hernandez-Galan et al. (1993).

Experimental top

The dehydroacetic acid (500 mg, 3 mmol) was treated with ethylbromoacetate (2 g, 12 mmol) in acetone in the presence of K2CO3 (1.6 g, 12 mmol). The reaction mixture was refluxed for 3 h monitored with TLC at regular intervals of 30 minutes. The reaction was quenched by addition of 1 N HCl (10 ml) and the aqueous layer was extracted with ethyl acetate three times. The combined organic layers were concentrated under reduced pressure. The crude residue was dissolved in hot ethanol. The slow evaporation of ethanol yielded colorless needle-like crystals (90%, 680 mg).

Refinement top

The H atoms were placed in calculated positions and allowed to ride on their carrier atoms with C—H = 0.93–0.96 Å and with Uiso = 1.2Ueq(C) for CH and CH2 and Uiso = 1.5Ueq(C) for CH3 groups.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Crystal Structure of Ethyl 2-(3-acetyl-6-methyl-2-oxo-2H-pyran-4-yloxy) acetate (50% ellipsoids).
Ethyl 2-(3-acetyl-6-methyl-2-oxo-2H-pyran-4-yloxy)acetate top
Crystal data top
C12H14O6Z = 2
Mr = 254.23F(000) = 268
Triclinic, P1Dx = 1.357 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.8258 (10) ÅCell parameters from 6664 reflections
b = 8.2722 (11) Åθ = 2.1–28.3°
c = 10.0838 (13) ŵ = 0.11 mm−1
α = 77.374 (7)°T = 298 K
β = 77.759 (6)°Rectangular prism, clear colourless
γ = 88.857 (7)°0.72 × 0.13 × 0.11 mm
V = 622.28 (14) Å3
Data collection top
Bruker SMART APEXII
diffractometer		3039 independent reflections
Radiation source: fine-focus sealed tube2330 reflections with I > 2σ(I)
graphiteRint = 0.036
Detector resolution: 83.33 pixels mm-1θmax = 28.3°, θmin = 2.1°
φ scans and ω scans with κ offsetsh = −10→10
Absorption correction: multi-scan
(SADABS; Bruker, 2001)		k = −11→10
Tmin = 0.925, Tmax = 0.988l = −13→13
14279 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)] = 0.050Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.159H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0773P)2 + 0.1512P]
where P = (Fo2 + 2Fc2)/3
3039 reflections(Δ/σ)max < 0.001
166 parametersΔρmax = 0.35 e Å−3
0 restraintsΔρmin = −0.20 e Å−3
Crystal data top
C12H14O6γ = 88.857 (7)°
Mr = 254.23V = 622.28 (14) Å3
Triclinic, P1Z = 2
a = 7.8258 (10) ÅMo Kα radiation
b = 8.2722 (11) ŵ = 0.11 mm−1
c = 10.0838 (13) ÅT = 298 K
α = 77.374 (7)°0.72 × 0.13 × 0.11 mm
β = 77.759 (6)°
Data collection top
Bruker SMART APEXII
diffractometer		3039 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)		2330 reflections with I > 2σ(I)
Tmin = 0.925, Tmax = 0.988Rint = 0.036
14279 measured reflectionsθmax = 28.3°
Refinement top
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.159Δρmax = 0.35 e Å−3
S = 1.04Δρmin = −0.20 e Å−3
3039 reflectionsAbsolute structure: ?
166 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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
O10.57091 (13)0.60585 (14)1.11130 (11)0.0528 (3)
C20.44227 (18)0.6846 (2)1.04378 (17)0.0494 (4)
C30.50118 (17)0.81700 (18)0.92489 (15)0.0438 (3)
C40.67613 (17)0.86621 (18)0.89085 (15)0.0419 (3)
C50.79728 (17)0.78287 (18)0.96663 (16)0.0445 (3)
H50.91420.81750.94330.053*
C60.74139 (18)0.65385 (19)1.07210 (15)0.0453 (3)
C6A0.8505 (2)0.5494 (2)1.15859 (19)0.0626 (5)
H6A10.97080.58511.12480.094*
H6A20.83790.43581.15370.094*
H6A30.81340.55971.25340.094*
C3A0.36798 (19)0.8935 (2)0.84701 (18)0.0525 (4)
C3B0.4174 (3)0.9705 (5)0.6972 (3)0.1171 (12)
H3B10.31990.96300.65480.176*
H3B20.51450.91380.65420.176*
H3B30.44991.08490.68540.176*
O3A0.21609 (15)0.8898 (2)0.90547 (17)0.0803 (5)
O40.72493 (13)0.99457 (14)0.78399 (13)0.0576 (3)
C1A0.9346 (2)1.1577 (2)0.60243 (17)0.0525 (4)
C2A0.8981 (2)1.0641 (2)0.74992 (18)0.0562 (4)
H2A10.98160.97680.76220.067*
H2A20.90881.13780.81060.067*
O20.29702 (14)0.62711 (18)1.09368 (15)0.0704 (4)
O1A0.8501 (2)1.1503 (2)0.51873 (16)0.0947 (6)
O1B1.08032 (15)1.24797 (15)0.57701 (11)0.0587 (3)
C1E1.1521 (3)1.3319 (3)0.43439 (19)0.0748 (6)
H1E11.06941.41010.39960.090*
H1E21.17691.25230.37550.090*
C2E1.3156 (3)1.4200 (4)0.4343 (3)0.1057 (9)
H2E11.28821.50370.48750.159*
H2E21.37121.47100.34040.159*
H2E31.39301.34240.47470.159*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0358 (5)0.0632 (7)0.0518 (6)−0.0105 (5)−0.0048 (4)0.0003 (5)
C20.0325 (7)0.0602 (9)0.0533 (8)−0.0079 (6)−0.0035 (6)−0.0126 (7)
C30.0282 (6)0.0524 (8)0.0514 (8)−0.0040 (6)−0.0069 (6)−0.0141 (6)
C40.0306 (6)0.0461 (7)0.0475 (7)−0.0052 (5)−0.0062 (5)−0.0084 (6)
C50.0280 (6)0.0528 (8)0.0512 (8)−0.0071 (5)−0.0080 (5)−0.0077 (6)
C60.0338 (7)0.0543 (8)0.0469 (7)−0.0054 (6)−0.0076 (6)−0.0096 (6)
C6A0.0500 (9)0.0741 (11)0.0578 (10)−0.0051 (8)−0.0168 (7)0.0039 (8)
C3A0.0312 (7)0.0618 (9)0.0665 (10)−0.0022 (6)−0.0129 (6)−0.0156 (8)
C3B0.0486 (11)0.212 (3)0.0718 (14)0.0101 (15)−0.0214 (10)0.0165 (17)
O3A0.0314 (6)0.1083 (11)0.0932 (10)0.0034 (6)−0.0130 (6)−0.0053 (8)
O40.0332 (5)0.0616 (7)0.0687 (7)−0.0110 (5)−0.0157 (5)0.0110 (5)
C1A0.0461 (8)0.0541 (9)0.0544 (9)−0.0057 (7)−0.0108 (7)−0.0052 (7)
C2A0.0361 (7)0.0655 (10)0.0578 (9)−0.0158 (7)−0.0116 (6)0.0090 (7)
O20.0346 (6)0.0894 (9)0.0752 (8)−0.0196 (6)−0.0017 (5)−0.0007 (7)
O1A0.0861 (11)0.1290 (14)0.0670 (9)−0.0384 (10)−0.0321 (8)0.0022 (9)
O1B0.0544 (7)0.0653 (7)0.0469 (6)−0.0197 (5)−0.0051 (5)0.0040 (5)
C1E0.0799 (13)0.0853 (13)0.0456 (9)−0.0179 (10)−0.0010 (9)0.0044 (9)
C2E0.0910 (17)0.127 (2)0.0702 (13)−0.0493 (15)0.0077 (12)0.0197 (13)
Geometric parameters (Å, °) top
O1—C61.3501 (16)C3B—H3B10.9600
O1—C21.404 (2)C3B—H3B20.9600
C2—O21.2024 (17)C3B—H3B30.9600
C2—C31.436 (2)O4—C2A1.4256 (17)
C3—C41.3856 (17)C1A—O1A1.189 (2)
C3—C3A1.486 (2)C1A—O1B1.3228 (18)
C4—O41.3326 (18)C1A—C2A1.489 (2)
C4—C51.417 (2)C2A—H2A10.9700
C5—C61.337 (2)C2A—H2A20.9700
C5—H50.9300O1B—C1E1.450 (2)
C6—C6A1.481 (2)C1E—C2E1.485 (3)
C6A—H6A10.9600C1E—H1E10.9700
C6A—H6A20.9600C1E—H1E20.9700
C6A—H6A30.9600C2E—H2E10.9600
C3A—O3A1.2073 (19)C2E—H2E20.9600
C3A—C3B1.476 (3)C2E—H2E30.9600
C6—O1—C2122.89 (12)H3B1—C3B—H3B2109.5
O2—C2—O1113.96 (15)C3A—C3B—H3B3109.5
O2—C2—C3129.34 (16)H3B1—C3B—H3B3109.5
O1—C2—C3116.68 (12)H3B2—C3B—H3B3109.5
C4—C3—C2118.59 (13)C4—O4—C2A121.02 (12)
C4—C3—C3A124.32 (14)O1A—C1A—O1B124.77 (16)
C2—C3—C3A117.09 (12)O1A—C1A—C2A126.07 (16)
O4—C4—C3117.09 (13)O1B—C1A—C2A109.14 (14)
O4—C4—C5121.74 (12)O4—C2A—C1A108.53 (13)
C3—C4—C5121.17 (13)O4—C2A—H2A1110.0
C6—C5—C4119.19 (12)C1A—C2A—H2A1110.0
C6—C5—H5120.4O4—C2A—H2A2110.0
C4—C5—H5120.4C1A—C2A—H2A2110.0
C5—C6—O1121.31 (13)H2A1—C2A—H2A2108.4
C5—C6—C6A126.34 (14)C1A—O1B—C1E117.97 (14)
O1—C6—C6A112.35 (13)O1B—C1E—C2E107.09 (17)
C6—C6A—H6A1109.5O1B—C1E—H1E1110.3
C6—C6A—H6A2109.5C2E—C1E—H1E1110.3
H6A1—C6A—H6A2109.5O1B—C1E—H1E2110.3
C6—C6A—H6A3109.5C2E—C1E—H1E2110.3
H6A1—C6A—H6A3109.5H1E1—C1E—H1E2108.6
H6A2—C6A—H6A3109.5C1E—C2E—H2E1109.5
O3A—C3A—C3B118.99 (17)C1E—C2E—H2E2109.5
O3A—C3A—C3119.99 (16)H2E1—C2E—H2E2109.5
C3B—C3A—C3120.99 (14)C1E—C2E—H2E3109.5
C3A—C3B—H3B1109.5H2E1—C2E—H2E3109.5
C3A—C3B—H3B2109.5H2E2—C2E—H2E3109.5
C6—O1—C2—O2−179.01 (14)C2—O1—C6—C51.2 (2)
C6—O1—C2—C32.6 (2)C2—O1—C6—C6A−179.19 (14)
O2—C2—C3—C4177.25 (16)C4—C3—C3A—O3A−153.29 (17)
O1—C2—C3—C4−4.6 (2)C2—C3—C3A—O3A26.1 (2)
O2—C2—C3—C3A−2.2 (3)C4—C3—C3A—C3B28.5 (3)
O1—C2—C3—C3A175.96 (13)C2—C3—C3A—C3B−152.2 (2)
C2—C3—C4—O4−176.87 (13)C3—C4—O4—C2A173.81 (14)
C3A—C3—C4—O42.5 (2)C5—C4—O4—C2A−6.3 (2)
C2—C3—C4—C53.3 (2)C4—O4—C2A—C1A159.18 (14)
C3A—C3—C4—C5−177.39 (14)O1A—C1A—C2A—O4−13.5 (3)
O4—C4—C5—C6−179.39 (14)O1B—C1A—C2A—O4168.37 (13)
C3—C4—C5—C60.5 (2)O1A—C1A—O1B—C1E−6.2 (3)
C4—C5—C6—O1−2.8 (2)C2A—C1A—O1B—C1E172.01 (16)
C4—C5—C6—C6A177.66 (16)C1A—O1B—C1E—C2E−178.72 (19)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C6A—H6A1···O2i0.962.533.462 (2)165
C5—H5···O3Ai0.932.383.3053 (19)174
C2A—H2A1···O3Ai0.972.573.355 (2)138
C2E—H2E2···O1ii0.962.543.484 (3)169
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1, z−1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C6A—H6A1···O2i0.962.533.462 (2)165
C5—H5···O3Ai0.932.383.3053 (19)174
C2A—H2A1···O3Ai0.972.573.355 (2)138
C2E—H2E2···O1ii0.962.543.484 (3)169
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1, z−1.
Acknowledgements top

The authors thank the Organization for the Prohibition of Chemical Weapons for financial support.

references
References top

Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2008). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.

Hernandez-Galan, R., Salva, J., Massannet, G. M. & Collado, I. G. (1993). Tetrahedron, 49, 1701–1702.

Prakash, O., Kumar, A. & Singh, S. P. (2004). Heterocycles, 63, 1193–1194.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.