Ethyl (E)-2-(2,7-dimethyl-5-oxo-4H,5H-pyrano[4,3-b]pyran-4-yl­idene)acetate

In the title compound, C₁₄H₁₄O₅, the two heterocyclic rings are coplanar (r.m.s. deviation = 0.008 Å), with the largest deviation from the mean plane being 0.012 (1) Å. The mean plane through the acetate group is inclined slightly with respect to the oxo­pyrano[4,3-b]pyran-4-yl system, as indicated by the dihedral angle of 1.70 (7)° between them. Two intra­molecular hydrogen bonds, completing S(6) ring motifs, are observed in the mol­ecule. In the crystal, mol­ecules are linked by weak C—H...O hydrogen bonds involving the same acceptor atom, forming chains propagating along the c-axis direction and enclosing R₂¹(6) ring motifs. The chains are linked via offset π–π inter­actions [inter­centroid distance = 3.622 (1) Å], involving inversion-related oxo­pyrano[4,3-b]pyran-4-yl ring systems, forming slabs parallel to the bc plane.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.043
• wR factor = 0.137
• Data-to-parameter ratio = 16.3

checkCIF/PLATON results

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Alert level G
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Theta(Min)           1 Note
PLAT933_ALERT_2_G Number of OMIT Records in Embedded .res File ...          1 Note
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density.          7 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   0 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check


checkCIF publication errors

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              Please specify the role of each of the co-authors
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   1 ALERT level A = Data missing that is essential or data in wrong format
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Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Ethyl (E)-2-(2,7-dimethyl-5-oxo-4H,5H-pyrano[4,3-b]pyran-4-ylidene)acetate

Crystal data

C14H14O5	Dx = 1.310 Mg m^−3
Mr = 262.25	Melting point: 376 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.5679 (12) Å	Cell parameters from 2939 reflections
b = 11.4330 (13) Å	θ = 2.5–27.1°
c = 12.7993 (15) Å	µ = 0.10 mm^−1
β = 108.257 (4)°	T = 296 K
V = 1329.6 (3) Å^3	Block, colourless
Z = 4	0.32 × 0.26 × 0.21 mm
F(000) = 552

Data collection

Bruker X8 APEX diffractometer	2939 independent reflections
Radiation source: fine-focus sealed tube	1909 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
φ and ω scans	θmax = 27.1°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −12→12
Tmin = 0.663, Tmax = 0.746	k = −14→14
16353 measured reflections	l = −13→16

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.137	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0699P)^2 + 0.1184P] where P = (Fo^2 + 2Fc^2)/3
2939 reflections	(Δ/σ)max < 0.001
180 parameters	Δρmax = 0.17 e Å^−3
0 restraints	Δρmin = −0.15 e Å^−3

Special details

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

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

	x	y	z	Uiso*/Ueq
C1	0.7176 (3)	0.4822 (2)	1.10578 (18)	0.1053 (9)
H1A	0.7896	0.5034	1.1742	0.158*
H1B	0.6384	0.5376	1.0884	0.158*
H1C	0.6801	0.4055	1.1122	0.158*
C2	0.7864 (2)	0.4820 (2)	1.01765 (16)	0.0901 (7)
H2A	0.8250	0.5590	1.0105	0.108*
H2B	0.8670	0.4263	1.0345	0.108*
C3	0.7183 (2)	0.43027 (15)	0.82769 (14)	0.0584 (5)
C4	0.59172 (17)	0.40172 (14)	0.73274 (13)	0.0523 (4)
H4	0.5000	0.3988	0.7433	0.063*
C5	0.59770 (16)	0.37903 (12)	0.62997 (12)	0.0442 (4)
C6	0.73205 (17)	0.38065 (13)	0.60097 (14)	0.0496 (4)
H6	0.8198	0.3960	0.6563	0.060*
C7	0.73778 (16)	0.36155 (14)	0.50021 (14)	0.0508 (4)
C8	0.48137 (16)	0.33460 (12)	0.43348 (13)	0.0453 (4)
C9	0.46732 (15)	0.35306 (12)	0.53543 (12)	0.0420 (4)
C10	0.31964 (17)	0.34808 (14)	0.54336 (13)	0.0488 (4)
C11	0.22563 (17)	0.30720 (14)	0.34851 (13)	0.0515 (4)
C12	0.35992 (17)	0.31137 (14)	0.33862 (14)	0.0519 (4)
H12	0.3739	0.2993	0.2707	0.062*
C13	0.08513 (19)	0.2864 (2)	0.26002 (16)	0.0752 (6)
H13A	0.0281	0.3571	0.2461	0.130 (10)*
H13B	0.0310	0.2259	0.2824	0.109 (8)*
H13C	0.1052	0.2627	0.1942	0.100 (7)*
C14	0.8690 (2)	0.36234 (18)	0.46180 (18)	0.0702 (6)
H14A	0.8813	0.2865	0.4338	0.109 (8)*
H14B	0.9548	0.3815	0.5222	0.100 (7)*
H14C	0.8558	0.4196	0.4046	0.102 (8)*
O1	0.67347 (14)	0.44936 (12)	0.91578 (10)	0.0756 (4)
O2	0.84654 (14)	0.43692 (14)	0.83266 (11)	0.0822 (5)
O3	0.61171 (11)	0.33840 (10)	0.41328 (9)	0.0557 (3)
O4	0.28225 (13)	0.36313 (13)	0.62435 (10)	0.0714 (4)
O5	0.20544 (11)	0.32427 (10)	0.44793 (9)	0.0546 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.110 (2)	0.129 (2)	0.0675 (13)	0.0096 (16)	0.0138 (14)	−0.0315 (14)
C2	0.0758 (15)	0.1147 (18)	0.0611 (12)	0.0024 (13)	−0.0055 (11)	−0.0259 (12)
C3	0.0485 (11)	0.0619 (11)	0.0556 (10)	0.0028 (8)	0.0030 (8)	−0.0001 (8)
C4	0.0406 (9)	0.0584 (10)	0.0531 (10)	−0.0007 (7)	0.0079 (7)	0.0046 (7)
C5	0.0348 (8)	0.0411 (8)	0.0515 (9)	0.0014 (6)	0.0061 (7)	0.0063 (6)
C6	0.0318 (8)	0.0524 (9)	0.0573 (10)	0.0009 (6)	0.0034 (7)	0.0027 (7)
C7	0.0304 (8)	0.0516 (9)	0.0676 (11)	0.0000 (6)	0.0111 (8)	−0.0013 (8)
C8	0.0329 (8)	0.0445 (8)	0.0577 (10)	−0.0009 (6)	0.0132 (7)	−0.0020 (7)
C9	0.0326 (8)	0.0417 (8)	0.0484 (9)	0.0006 (6)	0.0079 (7)	0.0046 (6)
C10	0.0350 (8)	0.0586 (10)	0.0495 (9)	−0.0038 (7)	0.0084 (8)	0.0085 (7)
C11	0.0386 (9)	0.0580 (10)	0.0532 (9)	−0.0056 (7)	0.0075 (7)	−0.0067 (7)
C12	0.0400 (9)	0.0636 (10)	0.0510 (9)	−0.0047 (7)	0.0125 (7)	−0.0103 (7)
C13	0.0416 (10)	0.1101 (17)	0.0657 (12)	−0.0123 (11)	0.0050 (9)	−0.0200 (11)
C14	0.0401 (10)	0.0861 (15)	0.0874 (14)	−0.0025 (9)	0.0243 (10)	−0.0080 (12)
O1	0.0609 (8)	0.1019 (10)	0.0552 (7)	0.0007 (7)	0.0055 (6)	−0.0196 (7)
O2	0.0457 (8)	0.1220 (12)	0.0674 (9)	−0.0020 (7)	0.0014 (7)	−0.0103 (8)
O3	0.0336 (6)	0.0732 (8)	0.0607 (7)	−0.0042 (5)	0.0151 (5)	−0.0125 (5)
O4	0.0439 (7)	0.1199 (11)	0.0522 (7)	−0.0059 (7)	0.0176 (6)	0.0078 (7)
O5	0.0321 (6)	0.0744 (8)	0.0546 (7)	−0.0077 (5)	0.0097 (5)	−0.0009 (5)

Geometric parameters (Å, º)

C1—C2	1.473 (3)	C7—C14	1.485 (2)
C1—H1A	0.9600	C8—O3	1.3513 (18)
C1—H1B	0.9600	C8—C9	1.369 (2)
C1—H1C	0.9600	C8—C12	1.418 (2)
C2—O1	1.458 (2)	C9—C10	1.449 (2)
C2—H2A	0.9700	C10—O4	1.2102 (19)
C2—H2B	0.9700	C10—O5	1.3869 (18)
C3—O2	1.211 (2)	C11—C12	1.331 (2)
C3—O1	1.344 (2)	C11—O5	1.3596 (19)
C3—C4	1.459 (2)	C11—C13	1.481 (2)
C4—C5	1.359 (2)	C12—H12	0.9300
C4—H4	0.9300	C13—H13A	0.9600
C5—C6	1.446 (2)	C13—H13B	0.9600
C5—C9	1.471 (2)	C13—H13C	0.9600
C6—C7	1.326 (2)	C14—H14A	0.9600
C6—H6	0.9300	C14—H14B	0.9600
C7—O3	1.3864 (18)	C14—H14C	0.9600
C2—C1—H1A	109.5	C9—C8—C12	123.09 (14)
C2—C1—H1B	109.5	C8—C9—C10	116.72 (14)
H1A—C1—H1B	109.5	C8—C9—C5	120.27 (13)
C2—C1—H1C	109.5	C10—C9—C5	123.00 (14)
H1A—C1—H1C	109.5	O4—C10—O5	114.81 (14)
H1B—C1—H1C	109.5	O4—C10—C9	127.65 (15)
O1—C2—C1	107.53 (19)	O5—C10—C9	117.54 (14)
O1—C2—H2A	110.2	C12—C11—O5	120.55 (14)
C1—C2—H2A	110.2	C12—C11—C13	127.24 (17)
O1—C2—H2B	110.2	O5—C11—C13	112.20 (14)
C1—C2—H2B	110.2	C11—C12—C8	118.81 (16)
H2A—C2—H2B	108.5	C11—C12—H12	120.6
O2—C3—O1	122.03 (16)	C8—C12—H12	120.6
O2—C3—C4	128.38 (18)	C11—C13—H13A	109.5
O1—C3—C4	109.59 (15)	C11—C13—H13B	109.5
C5—C4—C3	124.97 (16)	H13A—C13—H13B	109.5
C5—C4—H4	117.5	C11—C13—H13C	109.5
C3—C4—H4	117.5	H13A—C13—H13C	109.5
C4—C5—C6	123.81 (14)	H13B—C13—H13C	109.5
C4—C5—C9	123.55 (14)	C7—C14—H14A	109.5
C6—C5—C9	112.62 (14)	C7—C14—H14B	109.5
C7—C6—C5	123.96 (15)	H14A—C14—H14B	109.5
C7—C6—H6	118.0	C7—C14—H14C	109.5
C5—C6—H6	118.0	H14A—C14—H14C	109.5
C6—C7—O3	121.42 (14)	H14B—C14—H14C	109.5
C6—C7—C14	128.16 (16)	C3—O1—C2	116.73 (16)
O3—C7—C14	110.42 (15)	C8—O3—C7	118.41 (12)
O3—C8—C9	123.32 (14)	C11—O5—C10	123.28 (13)
O3—C8—C12	113.58 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O4	0.93	2.20	2.883 (2)	130
C6—H6···O2	0.93	2.24	2.894 (2)	127
C12—H12···O4^i	0.93	2.59	3.283 (2)	132
C13—H13C···O4^i	0.96	2.59	3.398 (2)	143

Symmetry code: (i) x, −y+1/2, z−1/2.