5-Hydr­oxy-7,8,2′-trimethoxy­flavone

Mol­ecules of the title compound, C₁₈H₁₆O₆, are almost planar. The dihedral angle between the benzopyran system and the benzene ring is 3.36 (5)°. In addition to an intra­molecular O—H...O hydrogen bond, mol­ecules are connected by weak inter­molecular C—H...O hydrogen bonds to form a two-dimensional framework.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.032
• wR factor = 0.094
• Data-to-parameter ratio = 9.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT088_ALERT_3_C Poor Data / Parameter Ratio ....................       9.34
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K

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

   1 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

---

Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software; data reduction: XCAD4 in WinGX (Farrugia, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP in WinGX; software used to prepare material for publication: SHELXL97.

5-hydroxy-7,8,2'-trimethoxyflavone

Crystal data

C18H16O6	Z = 2
Mr = 328.31	F(000) = 344
Triclinic, P1	Dx = 1.445 Mg m^−3 Dm = 1.44 Mg m^−3 Dm measured by KI-flotation
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.602 (2) Å	Cell parameters from 25 reflections
b = 8.7563 (10) Å	θ = 2–25°
c = 11.642 (3) Å	µ = 0.11 mm^−1
α = 85.252 (16)°	T = 297 K
β = 84.838 (12)°	Rectangular, yellow
γ = 78.469 (14)°	0.48 × 0.25 × 0.25 mm
V = 754.6 (3) Å^3

Data collection

Enraf–Nonius CAD-4 diffractometer	2289 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.006
Graphite monochromator	θmax = 25.0°, θmin = 2.4°
ω–2θ scans	h = 0→9
Absorption correction: ψ scan (North et al., 1968)	k = −10→10
Tmin = 0.950, Tmax = 0.970	l = −13→13
2854 measured reflections	2 standard reflections every 60 min
2635 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.032	All H-atom parameters refined
wR(F^2) = 0.094	w = 1/[σ^2(Fo^2) + (0.0491P)^2 + 0.1561P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
2635 reflections	Δρmax = 0.17 e Å^−3
282 parameters	Δρmin = −0.13 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.121 (7)

Special details

Experimental. The title compound is isolated by Jayaprakasam et al., 1999. ans recrystalized by slow evoparation from chloroform.

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.

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

	x	y	z	Uiso*/Ueq
O1	0.20733 (12)	0.12511 (10)	0.53528 (7)	0.0361 (2)
C4A	0.34276 (16)	−0.01273 (14)	0.70284 (10)	0.0346 (3)
O4	0.47174 (15)	−0.27918 (11)	0.68926 (9)	0.0532 (3)
O5	0.46405 (16)	−0.13720 (12)	0.87626 (9)	0.0554 (3)
C3	0.33979 (18)	−0.14198 (15)	0.52552 (11)	0.0373 (3)
O8	0.11739 (12)	0.39560 (10)	0.63927 (8)	0.0418 (3)
C2	0.24982 (16)	−0.00768 (14)	0.47611 (10)	0.0330 (3)
C4	0.39028 (17)	−0.15436 (14)	0.64239 (11)	0.0370 (3)
C8	0.20859 (17)	0.26449 (14)	0.69701 (11)	0.0351 (3)
O7	0.20324 (15)	0.40899 (11)	0.85597 (9)	0.0555 (3)
C8A	0.25430 (16)	0.12348 (14)	0.64586 (10)	0.0324 (3)
O10	0.27837 (15)	−0.23890 (11)	0.31331 (9)	0.0535 (3)
C9	0.18331 (16)	0.02433 (15)	0.35982 (10)	0.0341 (3)
C5	0.38222 (18)	−0.00593 (15)	0.81769 (11)	0.0392 (3)
C10	0.19688 (17)	−0.09107 (15)	0.28024 (11)	0.0388 (3)
C14	0.09967 (19)	0.17652 (16)	0.32604 (12)	0.0416 (3)
C11	0.1280 (2)	−0.05083 (19)	0.17325 (12)	0.0482 (4)
C6	0.33796 (19)	0.13257 (16)	0.87149 (11)	0.0411 (3)
C7	0.25224 (18)	0.26693 (15)	0.81095 (11)	0.0388 (3)
C13	0.0295 (2)	0.21488 (19)	0.21994 (12)	0.0499 (4)
C12	0.0445 (2)	0.10041 (19)	0.14386 (13)	0.0521 (4)
C16	0.2888 (3)	−0.3599 (2)	0.23698 (16)	0.0578 (4)
C17	0.2320 (3)	0.47588 (19)	0.56362 (16)	0.0560 (4)
C15	0.2580 (3)	0.4285 (2)	0.96614 (15)	0.0594 (4)
H5	0.485 (3)	−0.212 (3)	0.819 (2)	0.093 (7)*
H14	0.091 (2)	0.2547 (19)	0.3782 (14)	0.048 (4)*
H11	0.140 (2)	−0.129 (2)	0.1178 (15)	0.063 (5)*
H6	0.367 (2)	0.1340 (18)	0.9501 (14)	0.047 (4)*
H13	−0.030 (2)	0.321 (2)	0.2035 (16)	0.067 (5)*
H12	−0.004 (2)	0.126 (2)	0.0681 (16)	0.062 (5)*
H16A	0.353 (3)	−0.334 (2)	0.1638 (19)	0.077 (6)*
H16B	0.170 (3)	−0.375 (2)	0.2224 (16)	0.070 (5)*
H16C	0.352 (3)	−0.454 (3)	0.2758 (19)	0.097 (7)*
H15A	0.213 (3)	0.542 (2)	0.9777 (17)	0.082 (6)*
H15B	0.208 (3)	0.364 (3)	1.027 (2)	0.107 (8)*
H15C	0.385 (3)	0.397 (2)	0.9695 (18)	0.086 (7)*
H3	0.3696 (19)	−0.2320 (18)	0.4835 (13)	0.045 (4)*
H17A	0.153 (2)	0.562 (2)	0.5224 (16)	0.069 (5)*
H17B	0.304 (3)	0.404 (2)	0.5049 (17)	0.082 (6)*
H17C	0.311 (3)	0.516 (2)	0.6100 (18)	0.085 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0469 (5)	0.0305 (5)	0.0301 (5)	−0.0020 (4)	−0.0089 (4)	−0.0040 (3)
C4A	0.0365 (7)	0.0322 (6)	0.0351 (7)	−0.0059 (5)	−0.0060 (5)	−0.0005 (5)
O4	0.0715 (7)	0.0326 (5)	0.0532 (6)	0.0038 (5)	−0.0247 (5)	−0.0014 (4)
O5	0.0794 (8)	0.0403 (6)	0.0436 (6)	0.0031 (5)	−0.0267 (5)	0.0018 (4)
C3	0.0430 (7)	0.0307 (6)	0.0384 (7)	−0.0050 (5)	−0.0065 (5)	−0.0052 (5)
O8	0.0488 (5)	0.0333 (5)	0.0398 (5)	0.0013 (4)	−0.0080 (4)	0.0003 (4)
C2	0.0344 (6)	0.0326 (6)	0.0329 (6)	−0.0081 (5)	−0.0008 (5)	−0.0062 (5)
C4	0.0392 (7)	0.0309 (6)	0.0409 (7)	−0.0052 (5)	−0.0074 (5)	−0.0005 (5)
C8	0.0389 (7)	0.0309 (6)	0.0344 (6)	−0.0030 (5)	−0.0058 (5)	−0.0018 (5)
O7	0.0796 (7)	0.0408 (6)	0.0439 (6)	0.0052 (5)	−0.0204 (5)	−0.0149 (4)
C8A	0.0342 (6)	0.0348 (7)	0.0288 (6)	−0.0074 (5)	−0.0049 (5)	−0.0011 (5)
O10	0.0752 (7)	0.0381 (5)	0.0466 (6)	0.0003 (5)	−0.0169 (5)	−0.0131 (4)
C9	0.0337 (6)	0.0372 (7)	0.0319 (6)	−0.0075 (5)	−0.0027 (5)	−0.0027 (5)
C5	0.0436 (7)	0.0372 (7)	0.0364 (7)	−0.0048 (5)	−0.0113 (5)	0.0018 (5)
C10	0.0397 (7)	0.0413 (7)	0.0363 (7)	−0.0082 (5)	−0.0035 (5)	−0.0063 (5)
C14	0.0487 (8)	0.0389 (7)	0.0361 (7)	−0.0043 (6)	−0.0057 (6)	−0.0042 (6)
C11	0.0557 (9)	0.0545 (9)	0.0369 (7)	−0.0114 (7)	−0.0085 (6)	−0.0106 (6)
C6	0.0491 (8)	0.0422 (7)	0.0326 (7)	−0.0061 (6)	−0.0107 (6)	−0.0038 (5)
C7	0.0435 (7)	0.0365 (7)	0.0367 (7)	−0.0052 (5)	−0.0050 (5)	−0.0077 (5)
C13	0.0578 (9)	0.0480 (9)	0.0406 (8)	−0.0022 (7)	−0.0111 (6)	0.0034 (6)
C12	0.0597 (9)	0.0626 (9)	0.0348 (7)	−0.0101 (7)	−0.0147 (6)	0.0004 (7)
C16	0.0698 (11)	0.0483 (9)	0.0562 (10)	−0.0045 (8)	−0.0072 (9)	−0.0233 (8)
C17	0.0669 (10)	0.0392 (8)	0.0602 (10)	−0.0097 (7)	−0.0086 (8)	0.0092 (7)
C15	0.0779 (12)	0.0550 (10)	0.0462 (9)	−0.0035 (9)	−0.0146 (8)	−0.0204 (7)

Geometric parameters (Å, º)

O1—C8A	1.3649 (15)	C9—C10	1.4093 (18)
O1—C2	1.3687 (15)	C5—C6	1.3787 (19)
C4A—C8A	1.3941 (17)	C10—C11	1.386 (2)
C4A—C5	1.4050 (18)	C14—C13	1.379 (2)
C4A—C4	1.4434 (18)	C14—H14	0.941 (16)
O4—C4	1.2519 (16)	C11—C12	1.379 (2)
O5—C5	1.3542 (16)	C11—H11	0.966 (18)
O5—H5	0.95 (2)	C6—C7	1.3944 (19)
C3—C2	1.3486 (18)	C6—H6	0.963 (16)
C3—C4	1.4365 (19)	C13—C12	1.373 (2)
C3—H3	0.941 (15)	C13—H13	0.958 (19)
O8—C8	1.3742 (15)	C12—H12	0.976 (18)
O8—C17	1.4258 (19)	C16—H16A	0.97 (2)
C2—C9	1.4733 (18)	C16—H16B	0.97 (2)
C8—C8A	1.3831 (17)	C16—H16C	0.97 (2)
C8—C7	1.3989 (18)	C17—H17A	0.987 (19)
O7—C7	1.3595 (16)	C17—H17B	1.01 (2)
O7—C15	1.4173 (19)	C17—H17C	0.98 (2)
O10—C10	1.3592 (16)	C15—H15A	1.00 (2)
O10—C16	1.4239 (17)	C15—H15B	0.97 (3)
C9—C14	1.3979 (19)	C15—H15C	0.95 (2)
C8A—O1—C2	120.45 (10)	C9—C14—H14	118.3 (9)
C8A—C4A—C5	118.16 (12)	C12—C11—C10	120.95 (14)
C8A—C4A—C4	119.24 (11)	C12—C11—H11	119.3 (10)
C5—C4A—C4	122.61 (11)	C10—C11—H11	119.8 (10)
C5—O5—H5	102.4 (14)	C5—C6—C7	119.35 (12)
C2—C3—C4	122.24 (12)	C5—C6—H6	119.0 (9)
C2—C3—H3	119.9 (9)	C7—C6—H6	121.7 (9)
C4—C3—H3	117.9 (9)	O7—C7—C6	123.94 (12)
C8—O8—C17	113.37 (11)	O7—C7—C8	114.47 (11)
C3—C2—O1	120.73 (11)	C6—C7—C8	121.58 (12)
C3—C2—C9	129.40 (11)	C12—C13—C14	119.04 (14)
O1—C2—C9	109.87 (10)	C12—C13—H13	123.1 (11)
O4—C4—C3	122.57 (12)	C14—C13—H13	117.9 (11)
O4—C4—C4A	121.68 (12)	C13—C12—C11	120.48 (13)
C3—C4—C4A	115.75 (11)	C13—C12—H12	120.1 (10)
O8—C8—C8A	121.00 (11)	C11—C12—H12	119.4 (10)
O8—C8—C7	121.42 (11)	O10—C16—H16A	109.8 (11)
C8A—C8—C7	117.53 (11)	O10—C16—H16B	111.4 (11)
C7—O7—C15	119.10 (12)	H16A—C16—H16B	109.1 (16)
O1—C8A—C8	115.88 (11)	O10—C16—H16C	106.1 (13)
O1—C8A—C4A	121.54 (11)	H16A—C16—H16C	111.6 (17)
C8—C8A—C4A	122.58 (11)	H16B—C16—H16C	108.8 (17)
C10—O10—C16	119.09 (12)	O8—C17—H17A	106.6 (10)
C14—C9—C10	117.57 (11)	O8—C17—H17B	110.8 (11)
C14—C9—C2	118.86 (11)	H17A—C17—H17B	108.7 (15)
C10—C9—C2	123.57 (11)	O8—C17—H17C	108.5 (12)
O5—C5—C6	119.69 (12)	H17A—C17—H17C	111.1 (16)
O5—C5—C4A	119.53 (12)	H17B—C17—H17C	111.0 (17)
C6—C5—C4A	120.78 (12)	O7—C15—H15A	104.1 (12)
O10—C10—C11	122.92 (12)	O7—C15—H15B	112.3 (15)
O10—C10—C9	117.43 (11)	H15A—C15—H15B	111.2 (18)
C11—C10—C9	119.65 (13)	O7—C15—H15C	111.6 (13)
C13—C14—C9	122.30 (13)	H15A—C15—H15C	113.5 (17)
C13—C14—H14	119.4 (9)	H15B—C15—H15C	104.3 (19)
C4—C3—C2—O1	2.0 (2)	C4—C4A—C5—O5	−1.7 (2)
C4—C3—C2—C9	−177.97 (12)	C8A—C4A—C5—C6	−1.4 (2)
C8A—O1—C2—C3	−0.48 (17)	C4—C4A—C5—C6	178.58 (12)
C8A—O1—C2—C9	179.49 (10)	C16—O10—C10—C11	−2.2 (2)
C2—C3—C4—O4	179.05 (12)	C16—O10—C10—C9	177.71 (13)
C2—C3—C4—C4A	−1.56 (19)	C14—C9—C10—O10	179.96 (11)
C8A—C4A—C4—O4	179.10 (12)	C2—C9—C10—O10	−0.95 (19)
C5—C4A—C4—O4	−0.8 (2)	C14—C9—C10—C11	−0.09 (19)
C8A—C4A—C4—C3	−0.29 (18)	C2—C9—C10—C11	179.00 (12)
C5—C4A—C4—C3	179.76 (12)	C10—C9—C14—C13	1.0 (2)
C17—O8—C8—C8A	−83.45 (15)	C2—C9—C14—C13	−178.17 (13)
C17—O8—C8—C7	99.14 (15)	O10—C10—C11—C12	179.22 (13)
C2—O1—C8A—C8	178.63 (10)	C9—C10—C11—C12	−0.7 (2)
C2—O1—C8A—C4A	−1.41 (17)	O5—C5—C6—C7	−179.42 (12)
O8—C8—C8A—O1	1.60 (17)	C4A—C5—C6—C7	0.3 (2)
C7—C8—C8A—O1	179.10 (11)	C15—O7—C7—C6	7.1 (2)
O8—C8—C8A—C4A	−178.36 (11)	C15—O7—C7—C8	−173.29 (14)
C7—C8—C8A—C4A	−0.85 (19)	C5—C6—C7—O7	−179.91 (13)
C5—C4A—C8A—O1	−178.30 (11)	C5—C6—C7—C8	0.5 (2)
C4—C4A—C8A—O1	1.75 (18)	O8—C8—C7—O7	−2.37 (18)
C5—C4A—C8A—C8	1.66 (19)	C8A—C8—C7—O7	−179.87 (11)
C4—C4A—C8A—C8	−178.29 (11)	O8—C8—C7—C6	177.23 (12)
O1—C2—C9—C14	2.86 (16)	C8A—C8—C7—C6	−0.3 (2)
C3—C2—C9—C10	3.7 (2)	C9—C14—C13—C12	−1.0 (2)
O1—C2—C9—C10	−176.22 (11)	C14—C13—C12—C11	0.2 (2)
C8A—C4A—C5—O5	178.37 (11)	C10—C11—C12—C13	0.7 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5···O4	0.95 (2)	1.69 (2)	2.5855 (15)	156 (2)
C6—H6···O5^i	0.962 (16)	2.496 (16)	3.4250 (19)	162.4 (13)
C13—H13···O7^ii	0.961 (17)	2.540 (17)	3.497 (2)	174.1 (15)
C16—H16C···O4^iii	0.97 (2)	2.47 (3)	3.402 (2)	161.5 (19)

Symmetry codes: (i) −x+1, −y, −z+2; (ii) −x, −y+1, −z+1; (iii) −x+1, −y−1, −z+1.