1-(5-Hydroxy-7-methoxy-2,2-dimethyl-2H-chromen-6-yl)ethan-1-one

The title chromene, C₁₄H₁₆O₄, was isolated from the stems of Polyalthia plagioneura Diels. The mol­ecular structure is stabilized by an intra­molecular O–H...O hydrogen bond, which generates an S(6) ring. In the crystal, the mol­ecules are linked by C—H...O inter­actions, generating [010] chains.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.059
• wR factor = 0.159
• Data-to-parameter ratio = 13.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.595         37

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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

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S1. Comment

The title chromene was isolated from plants such as Remirea maritima (Allan et al., 1969), Euodia lunu-ankenda (Manandhar et al., 1985) and Evodia lepta (Li et al., 1997). In our ongoing studies of natural products with biological activity we isolated the chromene from the 75% EtOH extract of the stems of Polyalthia plagioneura, a plant used as a flok medicine which were collected from Bawangling, Hainan Province, P. R. China. We have undertaken the X-ray crystal structure analysis of the title compound in order to establish its molecular structure and relative stereochemistry.

The hydrogen bonds and angles are listed in Table 1.

Related literature

For medicinal and botanical background to the title compound, see: Allan et al. (1969); Manandhar et al. (1985); Li et al. (1997).

S2. Experimental

Air-dried stems of Polyalthia plagioneura (20 kg) were ground and percolated (4 × 3 h) with 75% EtOH at 60°C, which was suspended in 5 L water and then partitioned with chloroform, ethyl acetate and n-BuOH, successively, yielding a chloroform extract, an ethyl acetate extract and a n-BuOH extract, respectively. The chloroform extract was subjected to a silica gel CC column using petroleum ether as first eluent and then increasing the polarity with EtOAc, to afford 33 fractions. Fraction 5 was further separated by column chromatography with a gradient of chloroform–ether–EtOAc to give the title compound. The crude product was recrystallised from ethyl acetate to yield colourless blocks of (I).

S3. Refinement

H atoms bonded to C atoms were palced in geometrically calculated position and were refined using a riding model, with U_iso(H) = 1.2 Ueq(C). H atoms attached to O atoms were found in a difference Fourier synthesis and were refined using a riding model, with the O—H distances fixed as initially found and with U_iso(H) values set at 1.5 Ueq(O).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. View of the title compound with displacement ellipsoids drawn at the 30% probability level.

1-(5-Hydroxy-7-methoxy-2,2-dimethyl-2H-chromen-6-yl)ethan-1-one

Crystal data

C14H16O4	Z = 2
Mr = 248.28	F(000) = 264
Triclinic, P1	Dx = 1.297 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.3797 (9) Å	Cell parameters from 1208 reflections
b = 8.0066 (10) Å	θ = 2.6–24.1°
c = 11.2878 (14) Å	µ = 0.10 mm^−1
α = 77.948 (1)°	T = 298 K
β = 77.411 (1)°	Block, colourless
γ = 84.465 (2)°	0.45 × 0.40 × 0.39 mm
V = 635.67 (14) Å^3

Data collection

Bruker SMART CCD diffractometer	2217 independent reflections
Radiation source: fine-focus sealed tube	1361 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
ω scans	θmax = 25.0°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −8→8
Tmin = 0.959, Tmax = 0.964	k = −8→9
3335 measured reflections	l = −13→13

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)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.159	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0801P)^2] where P = (Fo^2 + 2Fc^2)/3
2217 reflections	(Δ/σ)max < 0.001
167 parameters	Δρmax = 0.26 e Å^−3
0 restraints	Δρmin = −0.23 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.

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	0.1836 (2)	0.20248 (18)	0.25325 (13)	0.0529 (5)
O2	0.2390 (2)	0.76852 (19)	0.29434 (15)	0.0659 (5)
H2	0.2508	0.8241	0.3453	0.099*
O3	0.2742 (3)	0.8220 (2)	0.49648 (17)	0.0720 (6)
O4	0.2615 (2)	0.30717 (19)	0.63521 (13)	0.0604 (5)
C1	0.2377 (3)	0.2453 (3)	0.11859 (19)	0.0534 (7)
C2	0.2004 (4)	0.4317 (3)	0.0732 (2)	0.0584 (7)
H2A	0.1813	0.4684	−0.0072	0.070*
C3	0.1938 (3)	0.5467 (3)	0.1434 (2)	0.0546 (7)
H3	0.1751	0.6624	0.1116	0.066*
C4	0.2160 (3)	0.4900 (3)	0.27044 (19)	0.0431 (6)
C5	0.2349 (3)	0.6020 (3)	0.3466 (2)	0.0451 (6)
C6	0.2498 (3)	0.5431 (3)	0.47159 (19)	0.0419 (5)
C7	0.2432 (3)	0.3632 (3)	0.51639 (19)	0.0429 (6)
C8	0.2232 (3)	0.2528 (3)	0.44272 (19)	0.0433 (5)
H8	0.2184	0.1360	0.4741	0.052*
C9	0.2101 (3)	0.3175 (3)	0.32112 (19)	0.0411 (5)
C10	0.1212 (4)	0.1353 (3)	0.0740 (2)	0.0695 (8)
H10A	0.1443	0.0172	0.1090	0.104*
H10B	0.1534	0.1517	−0.0146	0.104*
H10C	−0.0081	0.1672	0.0992	0.104*
C11	0.4434 (4)	0.1947 (4)	0.0849 (2)	0.0791 (8)
H11A	0.5131	0.2610	0.1191	0.119*
H11B	0.4831	0.2157	−0.0035	0.119*
H11C	0.4640	0.0754	0.1176	0.119*
C12	0.2686 (3)	0.6685 (3)	0.5448 (2)	0.0501 (6)
C13	0.2816 (3)	0.6241 (3)	0.6777 (2)	0.0598 (7)
H13A	0.2903	0.7267	0.7070	0.090*
H13B	0.3900	0.5500	0.6867	0.090*
H13C	0.1727	0.5670	0.7251	0.090*
C14	0.2647 (4)	0.1275 (3)	0.6819 (2)	0.0717 (8)
H14A	0.1481	0.0845	0.6811	0.108*
H14B	0.2846	0.1051	0.7652	0.108*
H14C	0.3635	0.0720	0.6310	0.108*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0793 (12)	0.0426 (10)	0.0413 (9)	−0.0099 (8)	−0.0147 (8)	−0.0124 (7)
O2	0.0982 (14)	0.0346 (10)	0.0677 (11)	−0.0076 (8)	−0.0267 (10)	−0.0039 (8)
O3	0.1000 (15)	0.0432 (11)	0.0818 (13)	−0.0087 (9)	−0.0265 (10)	−0.0213 (9)
O4	0.0955 (14)	0.0452 (10)	0.0444 (9)	−0.0021 (8)	−0.0218 (8)	−0.0104 (8)
C1	0.0680 (18)	0.0559 (16)	0.0383 (12)	−0.0089 (12)	−0.0100 (11)	−0.0119 (11)
C2	0.0750 (18)	0.0597 (17)	0.0403 (13)	−0.0108 (13)	−0.0151 (12)	−0.0023 (12)
C3	0.0694 (17)	0.0430 (14)	0.0500 (14)	−0.0079 (11)	−0.0164 (12)	0.0010 (11)
C4	0.0455 (14)	0.0384 (13)	0.0461 (13)	−0.0026 (10)	−0.0111 (10)	−0.0077 (10)
C5	0.0464 (14)	0.0335 (12)	0.0547 (14)	−0.0029 (9)	−0.0110 (10)	−0.0059 (10)
C6	0.0422 (13)	0.0392 (13)	0.0467 (13)	−0.0003 (10)	−0.0109 (10)	−0.0126 (10)
C7	0.0487 (14)	0.0425 (13)	0.0374 (12)	−0.0004 (10)	−0.0089 (10)	−0.0087 (10)
C8	0.0545 (15)	0.0321 (12)	0.0432 (12)	−0.0029 (10)	−0.0097 (10)	−0.0069 (10)
C9	0.0452 (14)	0.0394 (13)	0.0410 (12)	−0.0041 (10)	−0.0089 (10)	−0.0114 (10)
C10	0.097 (2)	0.0722 (19)	0.0490 (14)	−0.0204 (15)	−0.0228 (14)	−0.0173 (13)
C11	0.076 (2)	0.092 (2)	0.0690 (18)	−0.0014 (15)	−0.0054 (15)	−0.0255 (16)
C12	0.0460 (14)	0.0452 (15)	0.0628 (15)	−0.0024 (11)	−0.0109 (11)	−0.0191 (12)
C13	0.0643 (17)	0.0611 (17)	0.0636 (16)	−0.0029 (12)	−0.0148 (12)	−0.0322 (13)
C14	0.113 (2)	0.0547 (17)	0.0450 (14)	−0.0050 (15)	−0.0215 (14)	0.0016 (12)

Geometric parameters (Å, º)

O1—C9	1.367 (2)	C6—C12	1.460 (3)
O1—C1	1.460 (2)	C7—C8	1.371 (3)
O2—C5	1.341 (2)	C8—C9	1.383 (3)
O2—H2	0.8200	C8—H8	0.9300
O3—C12	1.237 (3)	C10—H10A	0.9600
O4—C7	1.354 (2)	C10—H10B	0.9600
O4—C14	1.424 (3)	C10—H10C	0.9600
C1—C2	1.493 (3)	C11—H11A	0.9600
C1—C10	1.513 (3)	C11—H11B	0.9600
C1—C11	1.519 (3)	C11—H11C	0.9600
C2—C3	1.326 (3)	C12—C13	1.490 (3)
C2—H2A	0.9300	C13—H13A	0.9600
C3—C4	1.451 (3)	C13—H13B	0.9600
C3—H3	0.9300	C13—H13C	0.9600
C4—C9	1.381 (3)	C14—H14A	0.9600
C4—C5	1.401 (3)	C14—H14B	0.9600
C5—C6	1.415 (3)	C14—H14C	0.9600
C6—C7	1.426 (3)
C9—O1—C1	118.89 (16)	O1—C9—C4	120.78 (18)
C5—O2—H2	109.5	O1—C9—C8	116.67 (18)
C7—O4—C14	118.00 (17)	C4—C9—C8	122.51 (19)
O1—C1—C2	110.59 (18)	C1—C10—H10A	109.5
O1—C1—C10	104.22 (17)	C1—C10—H10B	109.5
C2—C1—C10	112.3 (2)	H10A—C10—H10B	109.5
O1—C1—C11	106.92 (19)	C1—C10—H10C	109.5
C2—C1—C11	111.2 (2)	H10A—C10—H10C	109.5
C10—C1—C11	111.3 (2)	H10B—C10—H10C	109.5
C3—C2—C1	122.2 (2)	C1—C11—H11A	109.5
C3—C2—H2A	118.9	C1—C11—H11B	109.5
C1—C2—H2A	118.9	H11A—C11—H11B	109.5
C2—C3—C4	119.3 (2)	C1—C11—H11C	109.5
C2—C3—H3	120.3	H11A—C11—H11C	109.5
C4—C3—H3	120.3	H11B—C11—H11C	109.5
C9—C4—C5	117.9 (2)	O3—C12—C6	119.8 (2)
C9—C4—C3	118.6 (2)	O3—C12—C13	116.2 (2)
C5—C4—C3	123.4 (2)	C6—C12—C13	124.0 (2)
O2—C5—C4	116.2 (2)	C12—C13—H13A	109.5
O2—C5—C6	121.7 (2)	C12—C13—H13B	109.5
C4—C5—C6	122.1 (2)	H13A—C13—H13B	109.5
C5—C6—C7	116.38 (19)	C12—C13—H13C	109.5
C5—C6—C12	118.6 (2)	H13A—C13—H13C	109.5
C7—C6—C12	125.0 (2)	H13B—C13—H13C	109.5
O4—C7—C8	121.91 (19)	O4—C14—H14A	109.5
O4—C7—C6	116.15 (18)	O4—C14—H14B	109.5
C8—C7—C6	121.93 (19)	H14A—C14—H14B	109.5
C7—C8—C9	119.2 (2)	O4—C14—H14C	109.5
C7—C8—H8	120.4	H14A—C14—H14C	109.5
C9—C8—H8	120.4	H14B—C14—H14C	109.5
C9—O1—C1—C2	−36.1 (3)	C5—C6—C7—O4	178.63 (19)
C9—O1—C1—C10	−157.02 (19)	C12—C6—C7—O4	−2.0 (3)
C9—O1—C1—C11	85.1 (2)	C5—C6—C7—C8	−0.1 (3)
O1—C1—C2—C3	25.1 (3)	C12—C6—C7—C8	179.2 (2)
C10—C1—C2—C3	141.0 (2)	O4—C7—C8—C9	−178.26 (18)
C11—C1—C2—C3	−93.6 (3)	C6—C7—C8—C9	0.4 (3)
C1—C2—C3—C4	−2.5 (4)	C1—O1—C9—C4	25.4 (3)
C2—C3—C4—C9	−11.4 (3)	C1—O1—C9—C8	−157.02 (19)
C2—C3—C4—C5	171.5 (2)	C5—C4—C9—O1	177.07 (19)
C9—C4—C5—O2	−179.63 (18)	C3—C4—C9—O1	−0.1 (3)
C3—C4—C5—O2	−2.6 (3)	C5—C4—C9—C8	−0.4 (3)
C9—C4—C5—C6	0.7 (3)	C3—C4—C9—C8	−177.6 (2)
C3—C4—C5—C6	177.72 (19)	C7—C8—C9—O1	−177.73 (18)
O2—C5—C6—C7	179.90 (18)	C7—C8—C9—C4	−0.2 (3)
C4—C5—C6—C7	−0.4 (3)	C5—C6—C12—O3	−1.2 (3)
O2—C5—C6—C12	0.5 (3)	C7—C6—C12—O3	179.5 (2)
C4—C5—C6—C12	−179.84 (19)	C5—C6—C12—C13	178.7 (2)
C14—O4—C7—C8	1.7 (3)	C7—C6—C12—C13	−0.6 (4)
C14—O4—C7—C6	−177.06 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3	0.82	1.75	2.479 (2)	147
C8—H8···O3^i	0.93	2.48	3.374 (3)	162

Symmetry code: (i) x, y−1, z.