5,6-Dimethyl-1,2,9,10-tetra-hydro-pyrano[3,2-f]chromene-3,8-dione.

The title mol-ecule, C(14)H(14)O(4), lies on a twofold rotation axis that bis-ects the central benzene ring, with only one half-mol-ecule in the asymmetric unit. The pyran-one systems adopt distorted twist- boat conformations, with the two methyl-ene C atoms displaced by 0.537 (1) and 0.163 (2) Å from the best-fit plane through the remaining five C and O atoms (r.m.s. deviation = 0.073 Å). In the crystal, bifurcated C-H⋯(O,O) hydrogen bonds link pairs of adjacent mol-ecules in an obverse fashion, stacking mol-ecules along c. These contacts are further stabilized by very weak π-π inter-actions between adjacent benzene rings with centroid-centroid distances of 4.1951 (4) Å. Additional C-H⋯O contacts link these stacks, giving a three-dimensional network.

Related literature

For the synthesis, see: Lecea et al. (2010 ▶). For details of the Cambridge Structural Database, see: Allen (2002 ▶) and for related structures, see: Cameron et al. (2011 ▶); Goswami et al. (2011 ▶). For standard bond lengths, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C14H14O4

M = 246.25

Monoclinic,

a = 16.0726 (2) Å

b = 8.7982 (1) Å

c = 8.0555 (1) Å

β = 96.1134 (7)°

V = 1132.65 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.11 mm−1

T = 92 K

0.53 × 0.50 × 0.22 mm

Data collection

Bruker APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2011 ▶) T min = 0.570, T max = 0.748

9744 measured reflections

2989 independent reflections

2358 reflections with I > 2σ(I)

R int = 0.038

Refinement

R[F 2 > 2σ(F 2)] = 0.050

wR(F 2) = 0.148

S = 1.08

2989 reflections

83 parameters

H-atom parameters constrained

Δρmax = 0.47 e Å−3

Δρmin = −0.38 e Å−3

Data collection: APEX2 (Bruker, 2011 ▶); cell refinement: APEX2 (Bruker, 2011 ▶) and SAINT (Bruker, 2011 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶) and TITAN2000 (Hunter & Simpson, 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) and TITAN2000; molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97, enCIFer (Allen et al., 2004 ▶), PLATON (Spek, 2009 ▶) and publCIF (Westrip 2010 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812027699/bt5941sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812027699/bt5941Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812027699/bt5941Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C14H14O4	F(000) = 520
Mr = 246.25	Dx = 1.444 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3955 reflections
a = 16.0726 (2) Å	θ = 2.6–38.3°
b = 8.7982 (1) Å	µ = 0.11 mm−1
c = 8.0555 (1) Å	T = 92 K
β = 96.1134 (7)°	Rectangular block, yellow
V = 1132.65 (2) Å3	0.53 × 0.50 × 0.22 mm
Z = 4

Bruker APEXII CCD area-detector diffractometer	2989 independent reflections
Radiation source: fine-focus sealed tube	2358 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
φ & ω scans	θmax = 39.3°, θmin = 3.6°
Absorption correction: multi-scan (SADABS; Bruker, 2011)	h = −27→26
Tmin = 0.570, Tmax = 0.748	k = −14→7
9744 measured reflections	l = −13→14

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.148	H-atom parameters constrained
S = 1.08	w = 1/[σ2(Fo2) + (0.0702P)2 + 0.4368P] where P = (Fo2 + 2Fc2)/3
2989 reflections	(Δ/σ)max < 0.001
83 parameters	Δρmax = 0.47 e Å−3
0 restraints	Δρmin = −0.38 e Å−3

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 > 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.

	x	y	z	Uiso*/Ueq
O1	0.76307 (4)	−0.03359 (9)	0.53742 (9)	0.02826 (17)
C1	0.70230 (5)	−0.04789 (10)	0.61199 (10)	0.01983 (16)
O2	0.64973 (4)	0.07377 (7)	0.61147 (8)	0.01902 (14)
C2	0.68037 (5)	−0.18492 (10)	0.70770 (10)	0.02081 (16)
H2A	0.6997	−0.1700	0.8274	0.025*
H2B	0.7099	−0.2745	0.6682	0.025*
C3	0.58596 (5)	−0.21578 (9)	0.68795 (10)	0.01919 (15)
H3A	0.5684	−0.2533	0.5737	0.023*
H3B	0.5728	−0.2952	0.7681	0.023*
C4	0.53894 (4)	−0.07275 (8)	0.71898 (9)	0.01485 (14)
C5	0.57500 (4)	0.06647 (8)	0.68637 (9)	0.01470 (14)
C6	0.53839 (4)	0.20612 (8)	0.71558 (9)	0.01519 (14)
C61	0.57956 (5)	0.35308 (10)	0.67541 (12)	0.02167 (17)
H61A	0.6030	0.4022	0.7792	0.033*
H61B	0.5380	0.4204	0.6156	0.033*
H61C	0.6245	0.3325	0.6053	0.033*

	U11	U22	U33	U12	U13	U23
O1	0.0216 (3)	0.0340 (4)	0.0307 (3)	0.0048 (2)	0.0097 (2)	0.0013 (3)
C1	0.0175 (3)	0.0226 (4)	0.0194 (3)	0.0039 (2)	0.0021 (2)	−0.0023 (3)
O2	0.0158 (2)	0.0186 (3)	0.0232 (3)	0.00139 (18)	0.0047 (2)	0.0013 (2)
C2	0.0214 (3)	0.0204 (4)	0.0207 (3)	0.0070 (3)	0.0026 (3)	0.0000 (3)
C3	0.0220 (3)	0.0143 (3)	0.0212 (3)	0.0028 (2)	0.0018 (2)	−0.0018 (2)
C4	0.0165 (3)	0.0124 (3)	0.0152 (3)	0.0007 (2)	−0.0003 (2)	−0.0005 (2)
C5	0.0140 (3)	0.0145 (3)	0.0154 (3)	0.0003 (2)	0.0009 (2)	0.0001 (2)
C6	0.0150 (3)	0.0122 (3)	0.0178 (3)	−0.0004 (2)	−0.0007 (2)	0.0006 (2)
C61	0.0196 (3)	0.0149 (3)	0.0302 (4)	−0.0028 (2)	0.0012 (3)	0.0024 (3)

O1—C1	1.2065 (10)	C3—H3B	0.9900
C1—O2	1.3634 (10)	C4—C5	1.3920 (10)
C1—C2	1.4934 (13)	C4—C4i	1.3962 (14)
O2—C5	1.4018 (9)	C5—C6	1.3931 (10)
C2—C3	1.5329 (11)	C6—C6i	1.4058 (14)
C2—H2A	0.9900	C6—C61	1.5033 (11)
C2—H2B	0.9900	C61—H61A	0.9800
C3—C4	1.5025 (11)	C61—H61B	0.9800
C3—H3A	0.9900	C61—H61C	0.9800
O1—C1—O2	116.80 (8)	C5—C4—C4i	118.34 (4)
O1—C1—C2	126.11 (8)	C5—C4—C3	118.59 (7)
O2—C1—C2	117.07 (7)	C4i—C4—C3	123.06 (4)
C1—O2—C5	121.45 (6)	C4—C5—C6	123.53 (7)
C1—C2—C3	112.01 (7)	C4—C5—O2	120.97 (6)
C1—C2—H2A	109.2	C6—C5—O2	115.40 (6)
C3—C2—H2A	109.2	C5—C6—C6i	118.10 (4)
C1—C2—H2B	109.2	C5—C6—C61	121.25 (7)
C3—C2—H2B	109.2	C6i—C6—C61	120.66 (4)
H2A—C2—H2B	107.9	C6—C61—H61A	109.5
C4—C3—C2	110.14 (7)	C6—C61—H61B	109.5
C4—C3—H3A	109.6	H61A—C61—H61B	109.5
C2—C3—H3A	109.6	C6—C61—H61C	109.5
C4—C3—H3B	109.6	H61A—C61—H61C	109.5
C2—C3—H3B	109.6	H61B—C61—H61C	109.5
H3A—C3—H3B	108.1
O1—C1—O2—C5	176.44 (7)	C4i—C4—C5—O2	−174.81 (8)
C2—C1—O2—C5	−4.87 (11)	C3—C4—C5—O2	5.95 (11)
O1—C1—C2—C3	−142.07 (9)	C1—O2—C5—C4	−19.48 (11)
O2—C1—C2—C3	39.38 (10)	C1—O2—C5—C6	164.02 (7)
C1—C2—C3—C4	−49.20 (9)	C4—C5—C6—C6i	1.15 (14)
C2—C3—C4—C5	27.91 (10)	O2—C5—C6—C6i	177.55 (8)
C2—C3—C4—C4i	−151.29 (9)	C4—C5—C6—C61	−179.02 (7)
C4i—C4—C5—C6	1.40 (14)	O2—C5—C6—C61	−2.62 (11)
C3—C4—C5—C6	−177.84 (7)

D—H···A	D—H	H···A	D···A	D—H···A
C61—H61A···O1ii	0.98	2.54	3.3907 (11)	145
C2—H2A···O1iii	0.99	2.60	3.4301 (12)	142
C2—H2A···O2iii	0.99	2.64	3.4813 (10)	143
C2—H2B···O1iv	0.99	2.44	3.3528 (11)	154

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C61—H61A⋯O1i	0.98	2.54	3.3907 (11)	145
C2—H2A⋯O1ii	0.99	2.60	3.4301 (12)	142
C2—H2A⋯O2ii	0.99	2.64	3.4813 (10)	143
C2—H2B⋯O1iii	0.99	2.44	3.3528 (11)	154

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