(1E,4Z,6E)-5-Hy-droxy-1,7-bis-(2-meth-oxy-phen-yl)-1,4,6-hepta-trien-3-one.

In the title compound, C(21)H(20)O(4), the central hepta-trienone unit is approximately planar, with a maximum atomic deviation of 0.1121 (11) Å; the two benzene rings are twisted with respect to the hepta-trienone mean plane by 2.73 (5) and 29.31 (4)°. The mol-ecule exists in the enol form and the hy-droxy group forms an intra-molecular hydrogen bond with the neighboring carbonyl group. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

Related literature

For potential applications of curcumin and its derivatives in medicine, see: Reddy & Lokesh (1992 ▶); Sreejayan Rao (1997 ▶); Narlawar et al. (2008 ▶); Qiu et al. (2010 ▶). For the tautomerism of curcumin and its analogues, see: Gunasekaran et al. (2008 ▶).

Experimental

Crystal data

C21H20O4

M = 336.37

Triclinic,

a = 7.3234 (11) Å

b = 7.7960 (12) Å

c = 16.897 (3) Å

α = 96.819 (3)°

β = 95.641 (3)°

γ = 115.520 (2)°

V = 852.3 (2) Å3

Z = 2

Mo Kα radiation

μ = 0.09 mm−1

T = 150 K

0.30 × 0.20 × 0.20 mm

Data collection

Bruker SMART APEXII CCD diffractometer

5805 measured reflections

2998 independent reflections

2238 reflections with I > 2σ(I)

R int = 0.022

Refinement

R[F 2 > 2σ(F 2)] = 0.044

wR(F 2) = 0.120

S = 1.05

2998 reflections

229 parameters

H-atom parameters constrained

Δρmax = 0.19 e Å−3

Δρmin = −0.24 e Å−3

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1999 ▶); software used to prepare material for publication: SHELXL97 and publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681102469X/xu5219sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681102469X/xu5219Isup2.hkl

Supplementary material file. DOI: 10.1107/S160053681102469X/xu5219Isup3.cml

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

C21H20O4	Z = 2
Mr = 336.37	F(000) = 356
Triclinic, P1	Dx = 1.311 Mg m−3
Hall symbol: -P 1	Melting point: 397(2) K
a = 7.3234 (11) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.7960 (12) Å	Cell parameters from 500 reflections
c = 16.897 (3) Å	θ = 1.1–28.2°
α = 96.819 (3)°	µ = 0.09 mm−1
β = 95.641 (3)°	T = 150 K
γ = 115.520 (2)°	Block, yellow
V = 852.3 (2) Å3	0.30 × 0.20 × 0.20 mm

Bruker SMART APEXII CCD diffractometer	2238 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube, Bruker K760	Rint = 0.022
graphite	θmax = 25.2°, θmin = 2.5°
ω scans	h = −8→8
5805 measured reflections	k = −7→9
2998 independent reflections	l = −20→20

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.120	H-atom parameters constrained
S = 1.05	w = 1/[σ2(Fo2) + (0.0634P)2 + 0.0684P] where P = (Fo2 + 2Fc2)/3
2998 reflections	(Δ/σ)max = 0.009
229 parameters	Δρmax = 0.19 e Å−3
0 restraints	Δρmin = −0.24 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
C1	0.6037 (2)	0.3920 (3)	0.64590 (10)	0.0297 (4)
C2	0.5514 (3)	0.3937 (3)	0.72270 (10)	0.0344 (4)
H2	0.4929	0.2793	0.7428	0.041*
C3	0.5873 (3)	0.5672 (3)	0.76908 (10)	0.0354 (5)
H3	0.5524	0.5687	0.8205	0.042*
C4	0.6743 (3)	0.7384 (3)	0.74013 (10)	0.0338 (4)
H4	0.6964	0.8541	0.7716	0.041*
C5	0.7279 (2)	0.7363 (3)	0.66415 (9)	0.0297 (4)
H5	0.7877	0.8518	0.6450	0.036*
C6	0.6946 (2)	0.5643 (2)	0.61529 (9)	0.0268 (4)
C7	0.7506 (2)	0.5582 (2)	0.53473 (9)	0.0281 (4)
H7	0.7175	0.4365	0.5058	0.034*
C8	0.8438 (2)	0.7075 (3)	0.49809 (10)	0.0304 (4)
H8	0.8820	0.8307	0.5266	0.036*
C9	0.8905 (2)	0.6913 (3)	0.41590 (9)	0.0280 (4)
C10	0.8584 (2)	0.5123 (2)	0.37012 (9)	0.0272 (4)
H10	0.8122	0.4023	0.3937	0.033*
C11	0.8942 (2)	0.4988 (2)	0.29240 (9)	0.0268 (4)
C12	0.8535 (2)	0.3168 (2)	0.24370 (9)	0.0283 (4)
H12	0.8155	0.2092	0.2687	0.034*
C13	0.8668 (2)	0.2926 (3)	0.16534 (9)	0.0281 (4)
H13	0.9086	0.4020	0.1415	0.034*
C14	0.8221 (2)	0.1110 (2)	0.11348 (9)	0.0264 (4)
C15	0.8139 (2)	−0.0505 (2)	0.14426 (10)	0.0293 (4)
H15	0.8443	−0.0406	0.1999	0.035*
C16	0.7621 (2)	−0.2245 (3)	0.09447 (10)	0.0315 (4)
H16	0.7570	−0.3302	0.1163	0.038*
C17	0.7178 (3)	−0.2390 (3)	0.01173 (10)	0.0348 (4)
H17	0.6811	−0.3559	−0.0221	0.042*
C18	0.7274 (3)	−0.0814 (3)	−0.02129 (10)	0.0335 (4)
H18	0.6975	−0.0930	−0.0770	0.040*
C19	0.7815 (2)	0.0937 (2)	0.02861 (9)	0.0275 (4)
C20	0.4696 (3)	0.0470 (3)	0.62014 (13)	0.0528 (6)
H20A	0.5460	0.0455	0.6694	0.079*
H20B	0.4574	−0.0550	0.5788	0.079*
H20C	0.3353	0.0284	0.6290	0.079*
C21	0.7528 (3)	0.2469 (3)	−0.08326 (9)	0.0361 (4)
H21A	0.8425	0.2087	−0.1101	0.054*
H21B	0.7722	0.3714	−0.0938	0.054*
H21C	0.6129	0.1539	−0.1030	0.054*
O1	0.57382 (19)	0.22818 (18)	0.59524 (7)	0.0404 (3)
O2	0.95885 (19)	0.84396 (17)	0.38537 (7)	0.0373 (3)
O3	0.96478 (19)	0.65274 (18)	0.25677 (7)	0.0355 (3)
H3'	0.9801	0.7482	0.2883	0.053*
O4	0.79859 (17)	0.25673 (17)	0.00178 (6)	0.0335 (3)

	U11	U22	U33	U12	U13	U23
C1	0.0299 (9)	0.0292 (10)	0.0291 (9)	0.0131 (8)	0.0038 (7)	0.0041 (8)
C2	0.0337 (10)	0.0361 (11)	0.0333 (10)	0.0132 (8)	0.0080 (7)	0.0138 (8)
C3	0.0332 (9)	0.0475 (13)	0.0250 (9)	0.0171 (9)	0.0072 (7)	0.0067 (8)
C4	0.0335 (9)	0.0356 (11)	0.0288 (9)	0.0142 (8)	0.0035 (7)	−0.0010 (8)
C5	0.0314 (9)	0.0268 (10)	0.0273 (9)	0.0102 (8)	0.0047 (7)	0.0027 (7)
C6	0.0269 (8)	0.0258 (10)	0.0261 (9)	0.0108 (7)	0.0030 (7)	0.0040 (7)
C7	0.0315 (9)	0.0241 (10)	0.0258 (9)	0.0110 (8)	0.0033 (7)	0.0003 (7)
C8	0.0383 (10)	0.0222 (10)	0.0258 (9)	0.0102 (8)	0.0059 (7)	−0.0008 (7)
C9	0.0288 (9)	0.0245 (10)	0.0270 (9)	0.0085 (7)	0.0045 (7)	0.0046 (7)
C10	0.0312 (9)	0.0234 (9)	0.0245 (8)	0.0100 (7)	0.0046 (7)	0.0042 (7)
C11	0.0262 (8)	0.0236 (9)	0.0282 (9)	0.0091 (7)	0.0032 (7)	0.0052 (7)
C12	0.0313 (9)	0.0241 (10)	0.0287 (9)	0.0113 (8)	0.0066 (7)	0.0049 (7)
C13	0.0287 (9)	0.0260 (10)	0.0283 (9)	0.0107 (7)	0.0063 (7)	0.0052 (7)
C14	0.0243 (8)	0.0281 (10)	0.0264 (9)	0.0113 (7)	0.0065 (6)	0.0035 (7)
C15	0.0287 (9)	0.0302 (10)	0.0283 (9)	0.0122 (8)	0.0067 (7)	0.0048 (7)
C16	0.0328 (9)	0.0268 (10)	0.0371 (10)	0.0143 (8)	0.0099 (7)	0.0066 (8)
C17	0.0365 (10)	0.0283 (11)	0.0361 (10)	0.0133 (8)	0.0079 (8)	−0.0028 (8)
C18	0.0383 (10)	0.0351 (11)	0.0254 (9)	0.0157 (8)	0.0063 (7)	0.0005 (8)
C19	0.0262 (8)	0.0263 (10)	0.0299 (9)	0.0109 (7)	0.0076 (7)	0.0061 (7)
C20	0.0698 (14)	0.0275 (12)	0.0646 (14)	0.0198 (11)	0.0241 (11)	0.0186 (10)
C21	0.0405 (10)	0.0443 (12)	0.0284 (9)	0.0212 (9)	0.0099 (8)	0.0125 (8)
O1	0.0556 (8)	0.0249 (7)	0.0414 (7)	0.0157 (6)	0.0178 (6)	0.0098 (6)
O2	0.0537 (8)	0.0227 (7)	0.0312 (7)	0.0114 (6)	0.0141 (6)	0.0051 (5)
O3	0.0508 (8)	0.0248 (7)	0.0288 (6)	0.0138 (6)	0.0124 (6)	0.0052 (5)
O4	0.0454 (7)	0.0302 (7)	0.0265 (6)	0.0177 (6)	0.0079 (5)	0.0065 (5)

C1—O1	1.369 (2)	C12—H12	0.9300
C1—C2	1.389 (2)	C13—C14	1.460 (2)
C1—C6	1.406 (2)	C13—H13	0.9300
C2—C3	1.384 (3)	C14—C15	1.398 (2)
C2—H2	0.9300	C14—C19	1.414 (2)
C3—C4	1.382 (3)	C15—C16	1.384 (2)
C3—H3	0.9300	C15—H15	0.9300
C4—C5	1.380 (2)	C16—C17	1.384 (2)
C4—H4	0.9300	C16—H16	0.9300
C5—C6	1.398 (2)	C17—C18	1.386 (2)
C5—H5	0.9300	C17—H17	0.9300
C6—C7	1.461 (2)	C18—C19	1.388 (3)
C7—C8	1.332 (2)	C18—H18	0.9300
C7—H7	0.9300	C19—O4	1.359 (2)
C8—C9	1.466 (2)	C20—O1	1.425 (2)
C8—H8	0.9300	C20—H20A	0.9600
C9—O2	1.271 (2)	C20—H20B	0.9600
C9—C10	1.424 (2)	C20—H20C	0.9600
C10—C11	1.365 (2)	C21—O4	1.4283 (18)
C10—H10	0.9300	C21—H21A	0.9600
C11—O3	1.3297 (19)	C21—H21B	0.9600
C11—C12	1.445 (2)	C21—H21C	0.9600
C12—C13	1.334 (2)	O3—H3'	0.8200
O1—C1—C2	123.87 (16)	C12—C13—C14	126.25 (16)
O1—C1—C6	115.31 (14)	C12—C13—H13	116.9
C2—C1—C6	120.82 (16)	C14—C13—H13	116.9
C3—C2—C1	119.36 (17)	C15—C14—C19	117.82 (15)
C3—C2—H2	120.3	C15—C14—C13	122.64 (14)
C1—C2—H2	120.3	C19—C14—C13	119.53 (15)
C4—C3—C2	121.01 (16)	C16—C15—C14	121.97 (15)
C4—C3—H3	119.5	C16—C15—H15	119.0
C2—C3—H3	119.5	C14—C15—H15	119.0
C5—C4—C3	119.41 (17)	C17—C16—C15	119.04 (16)
C5—C4—H4	120.3	C17—C16—H16	120.5
C3—C4—H4	120.3	C15—C16—H16	120.5
C4—C5—C6	121.47 (16)	C16—C17—C18	120.78 (17)
C4—C5—H5	119.3	C16—C17—H17	119.6
C6—C5—H5	119.3	C18—C17—H17	119.6
C5—C6—C1	117.92 (15)	C17—C18—C19	120.17 (16)
C5—C6—C7	122.55 (15)	C17—C18—H18	119.9
C1—C6—C7	119.53 (15)	C19—C18—H18	119.9
C8—C7—C6	127.18 (16)	O4—C19—C18	124.39 (15)
C8—C7—H7	116.4	O4—C19—C14	115.44 (14)
C6—C7—H7	116.4	C18—C19—C14	120.18 (16)
C7—C8—C9	124.57 (16)	O1—C20—H20A	109.5
C7—C8—H8	117.7	O1—C20—H20B	109.5
C9—C8—H8	117.7	H20A—C20—H20B	109.5
O2—C9—C10	120.10 (14)	O1—C20—H20C	109.5
O2—C9—C8	117.60 (15)	H20A—C20—H20C	109.5
C10—C9—C8	122.29 (15)	H20B—C20—H20C	109.5
C11—C10—C9	121.33 (15)	O4—C21—H21A	109.5
C11—C10—H10	119.3	O4—C21—H21B	109.5
C9—C10—H10	119.3	H21A—C21—H21B	109.5
O3—C11—C10	121.55 (15)	O4—C21—H21C	109.5
O3—C11—C12	116.30 (14)	H21A—C21—H21C	109.5
C10—C11—C12	122.14 (15)	H21B—C21—H21C	109.5
C13—C12—C11	124.44 (16)	C1—O1—C20	118.23 (14)
C13—C12—H12	117.8	C11—O3—H3'	109.5
C11—C12—H12	117.8	C19—O4—C21	118.11 (13)
O1—C1—C2—C3	−179.73 (15)	O3—C11—C12—C13	−5.5 (2)
C6—C1—C2—C3	0.8 (2)	C10—C11—C12—C13	173.19 (15)
C1—C2—C3—C4	0.0 (3)	C11—C12—C13—C14	−178.32 (15)
C2—C3—C4—C5	−0.7 (2)	C12—C13—C14—C15	−18.2 (3)
C3—C4—C5—C6	0.6 (2)	C12—C13—C14—C19	160.64 (15)
C4—C5—C6—C1	0.1 (2)	C19—C14—C15—C16	−1.9 (2)
C4—C5—C6—C7	−179.81 (14)	C13—C14—C15—C16	176.95 (14)
O1—C1—C6—C5	179.67 (14)	C14—C15—C16—C17	0.3 (2)
C2—C1—C6—C5	−0.8 (2)	C15—C16—C17—C18	0.8 (2)
O1—C1—C6—C7	−0.4 (2)	C16—C17—C18—C19	−0.1 (3)
C2—C1—C6—C7	179.11 (15)	C17—C18—C19—O4	178.77 (14)
C5—C6—C7—C8	2.5 (3)	C17—C18—C19—C14	−1.6 (2)
C1—C6—C7—C8	−177.40 (16)	C15—C14—C19—O4	−177.76 (13)
C6—C7—C8—C9	−178.05 (15)	C13—C14—C19—O4	3.3 (2)
C7—C8—C9—O2	172.23 (16)	C15—C14—C19—C18	2.6 (2)
C7—C8—C9—C10	−6.7 (3)	C13—C14—C19—C18	−176.36 (15)
O2—C9—C10—C11	−1.9 (2)	C2—C1—O1—C20	4.7 (2)
C8—C9—C10—C11	177.04 (14)	C6—C1—O1—C20	−175.74 (15)
C9—C10—C11—O3	1.5 (2)	C18—C19—O4—C21	1.7 (2)
C9—C10—C11—C12	−177.04 (14)	C14—C19—O4—C21	−177.93 (13)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3'···O2	0.82	1.77	2.5003 (18)	147
C5—H5···O2i	0.93	2.45	3.351 (2)	162
C8—H8···O2i	0.93	2.49	3.413 (2)	169

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3′⋯O2	0.82	1.77	2.5003 (18)	147
C5—H5⋯O2i	0.93	2.45	3.351 (2)	162
C8—H8⋯O2i	0.93	2.49	3.413 (2)	169

Symmetry code: (i) .