organic compounds
rac-7-Methyl-3-[(7-methyl-4-oxochroman-3-yl)methyl]-4H-chromen-4-one
aDepartment of Chemistry, Annamalai University, Annamalai Nagar, Chidambaram, India, and bShasun Reaearch Centre, 27 Vandaloor Kelambakkam Road, Keezhakottaiyur, Meelakottaiyur Post, Chennai, India
*Correspondence e-mail: soma78@gmail.com
In the racemic title compound, C21H18O4, the chromone ring is essentially planar [maximum deviation from the least-squares plane = 0.026 (3) Å], with a dihedral angle of 78.18 (12)° between the benzene rings of the chromanone and chromenone moieties. In the crystal, there are weak π–π stacking interactions [minimum ring centroid separation = 3.9286 (17) Å].
Related literature
For backgound to bis-chromanones, see: Dean & Murray (1975); Santhosh & Balasubramanian (1991); Panja et al. (2009). For related structures, see: Ambartsumyan et al. (2012); Nyburg et al. (1986); Li et al. (2010).
Experimental
Crystal data
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Data collection: SMART (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; 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.
Supporting information
https://doi.org/10.1107/S1600536813009422/zs2250sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813009422/zs2250Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536813009422/zs2250Isup3.cml
In a dry single-neck round-bottom flask, 4-chloro-3-formyl chromene (1 mol) and sodium acetate (1.1 mol) was taken, and DMF (5 vol) was added. The reaction mixture was stirred at 70 – 80 °C for 7–8 h. The progress of the reaction was monitored by TLC. After completion of the reaction, the mixture was cooled to room temperature and then quenched with water, extracted with ethyl acetate and concentrated under reduced pressure, giving the crude bis-chromanone product. This product was purified on silica gel using ethyl acetate–hexane solvent, giving the pure title compound.
The chromanone moiety forms an important component in pharmacophores in a number of biologically active molecules of synthetic as well as natural origin. Bis-chromanones bridged by a methylene group at C3 of the ring are considered to be a biologically important class of molecules (Santhosh & Balasubramanian, 1991; Panja, et al., 2009). Herein we report the structure of the racemic title compound, C21H18O4, in which the dihedral angle between the phenyl rings of the two chromanone moieties is 78.18 (12)° (Fig. 1). The chromone ring is essentially planar [maximum deviation from the l.s. plane = 0.026 (3) Å (C15)], while in the chromanone ring the maximum deviation is 0.206 (4) Å (C19)]. In the chromanone ring system, the C19—C20 bond length is short [1.380 (5)]. The torsion angles about the central methylene carbon C12 (C15—C1—C12—C20 and C19—C20—C12—C1) are -93.91 (3) and -37.48 (4)°, respectively. The angle subtended at C12 by the C—C bonds (C1—C12—C20) is 114.87 (2)°. The olefinic bond length [C1—C15 = 1.324 (4) Å] is close to the values found in known chromanone systems (Ambartsumyan et al., 2012). Some examples of bis-chromanone structures are known (Dean & Murray, 1975). In the crystal, there are weak π···π stacking interactions [minimum ring centroid separation = 3.9286 (17) Å].
For backgound to bis-chromanones, see: Dean & Murray (1975); Santhosh & Balasubramanian (1991); Panja et al. (2009). For related structures, see: Ambartsumyan et al. (2012); Nyburg et al. (1986); Li et al. (2010).
Data collection: SMART (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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).Fig. 1. The molecular conformation and atom numbering scheme for the title compound, showing 50% probability displacement ellipsoids. |
C21H18O4 | F(000) = 704 |
Mr = 334.35 | Dx = 1.320 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2970 reflections |
a = 10.664 (2) Å | θ = 2.5–28.2° |
b = 6.6428 (13) Å | µ = 0.09 mm−1 |
c = 23.754 (5) Å | T = 293 K |
β = 91.11 (3)° | Crystal, yellow |
V = 1682.4 (6) Å3 | 0.44 × 0.22 × 0.22 mm |
Z = 4 |
Bruker SMART CCD diffractometer | 4032 independent reflections |
Radiation source: fine-focus sealed tube | 1982 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
φ and ω scans | θmax = 28.3°, θmin = 3.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2007) | h = −13→12 |
Tmin = 0.961, Tmax = 0.980 | k = −8→8 |
11780 measured reflections | l = −29→31 |
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)] = 0.059 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.180 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0748P)2 + 0.4282P] where P = (Fo2 + 2Fc2)/3 |
4032 reflections | (Δ/σ)max < 0.001 |
229 parameters | Δρmax = 0.43 e Å−3 |
0 restraints | Δρmin = −0.30 e Å−3 |
C21H18O4 | V = 1682.4 (6) Å3 |
Mr = 334.35 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.664 (2) Å | µ = 0.09 mm−1 |
b = 6.6428 (13) Å | T = 293 K |
c = 23.754 (5) Å | 0.44 × 0.22 × 0.22 mm |
β = 91.11 (3)° |
Bruker SMART CCD diffractometer | 4032 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2007) | 1982 reflections with I > 2σ(I) |
Tmin = 0.961, Tmax = 0.980 | Rint = 0.029 |
11780 measured reflections |
R[F2 > 2σ(F2)] = 0.059 | 0 restraints |
wR(F2) = 0.180 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.43 e Å−3 |
4032 reflections | Δρmin = −0.30 e Å−3 |
229 parameters |
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 | ||
O2 | −0.12544 (16) | −0.0887 (3) | 0.10824 (8) | 0.0673 (5) | |
O1 | 0.34094 (18) | 0.1176 (2) | −0.01163 (8) | 0.0682 (5) | |
C1 | 0.0420 (2) | 0.1514 (3) | 0.10862 (11) | 0.0573 (7) | |
C2 | 0.3259 (2) | 0.4731 (3) | −0.03163 (10) | 0.0472 (6) | |
O4 | 0.18080 (18) | 0.6629 (2) | 0.01958 (8) | 0.0729 (6) | |
C3 | 0.0456 (2) | −0.1335 (3) | 0.17464 (9) | 0.0471 (6) | |
C4 | 0.2280 (2) | 0.4997 (3) | 0.00924 (10) | 0.0537 (6) | |
C5 | −0.1317 (2) | −0.3631 (3) | 0.16993 (11) | 0.0566 (7) | |
H5 | −0.2075 | −0.4003 | 0.1529 | 0.068* | |
C6 | −0.0679 (2) | −0.1937 (3) | 0.15148 (10) | 0.0493 (6) | |
C7 | 0.3769 (2) | 0.2828 (3) | −0.04092 (10) | 0.0533 (6) | |
C8 | 0.0330 (3) | −0.4157 (4) | 0.23729 (12) | 0.0684 (8) | |
H8 | 0.0676 | −0.4909 | 0.2667 | 0.082* | |
O3 | 0.2109 (2) | 0.1038 (3) | 0.17275 (9) | 0.0836 (6) | |
C9 | 0.1091 (2) | 0.0457 (4) | 0.15384 (10) | 0.0550 (6) | |
C10 | 0.0960 (2) | −0.2503 (4) | 0.21857 (10) | 0.0604 (7) | |
H10 | 0.1726 | −0.2152 | 0.2351 | 0.072* | |
C11 | 0.4571 (3) | 0.6020 (4) | −0.10497 (12) | 0.0634 (7) | |
H11 | 0.4826 | 0.7100 | −0.1269 | 0.076* | |
C12 | 0.0952 (3) | 0.3414 (3) | 0.08411 (11) | 0.0606 (7) | |
H12A | 0.0263 | 0.4252 | 0.0708 | 0.073* | |
H12B | 0.1391 | 0.4145 | 0.1139 | 0.073* | |
C13 | 0.3700 (2) | 0.6324 (3) | −0.06455 (11) | 0.0581 (7) | |
H13 | 0.3392 | 0.7615 | −0.0587 | 0.070* | |
C14 | 0.5085 (2) | 0.4123 (4) | −0.11405 (11) | 0.0631 (7) | |
C15 | −0.0676 (3) | 0.0812 (4) | 0.09029 (12) | 0.0684 (8) | |
H15 | −0.1090 | 0.1553 | 0.0624 | 0.082* | |
C16 | −0.0817 (3) | −0.4749 (4) | 0.21350 (11) | 0.0605 (7) | |
C17 | 0.4669 (3) | 0.2547 (4) | −0.08142 (12) | 0.0652 (7) | |
H17 | 0.5001 | 0.1268 | −0.0868 | 0.078* | |
C18 | 0.6082 (3) | 0.3821 (5) | −0.15727 (14) | 0.0897 (10) | |
H18A | 0.5698 | 0.3752 | −0.1941 | 0.135* | |
H18B | 0.6525 | 0.2591 | −0.1495 | 0.135* | |
H18C | 0.6660 | 0.4930 | −0.1558 | 0.135* | |
C19 | 0.2677 (4) | 0.1520 (4) | 0.03518 (17) | 0.0991 (12) | |
H19 | 0.2205 | 0.0297 | 0.0418 | 0.119* | |
H1 | 0.3247 | 0.1687 | 0.0672 | 0.62 (11)* | |
C20 | 0.1836 (3) | 0.3097 (4) | 0.03647 (15) | 0.0846 (10) | |
H20 | 0.1236 | 0.2640 | 0.0074 | 0.102* | |
C21 | −0.1514 (3) | −0.6556 (5) | 0.23528 (16) | 0.0968 (11) | |
H21A | −0.1730 | −0.6333 | 0.2738 | 0.145* | |
H21B | −0.0990 | −0.7727 | 0.2328 | 0.145* | |
H21C | −0.2264 | −0.6758 | 0.2130 | 0.145* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O2 | 0.0557 (11) | 0.0714 (11) | 0.0742 (12) | −0.0134 (9) | −0.0163 (10) | 0.0252 (10) |
O1 | 0.0876 (14) | 0.0363 (8) | 0.0811 (13) | 0.0084 (8) | 0.0148 (11) | 0.0026 (8) |
C1 | 0.0505 (16) | 0.0538 (13) | 0.0673 (17) | −0.0022 (12) | −0.0023 (13) | 0.0107 (12) |
C2 | 0.0488 (14) | 0.0389 (11) | 0.0536 (14) | −0.0033 (10) | −0.0045 (12) | −0.0018 (10) |
O4 | 0.0857 (14) | 0.0385 (9) | 0.0954 (14) | 0.0122 (9) | 0.0249 (11) | 0.0127 (9) |
C3 | 0.0463 (14) | 0.0516 (12) | 0.0434 (13) | 0.0032 (10) | 0.0013 (11) | 0.0001 (10) |
C4 | 0.0595 (16) | 0.0373 (11) | 0.0643 (16) | 0.0021 (11) | 0.0007 (13) | 0.0061 (11) |
C5 | 0.0528 (15) | 0.0562 (14) | 0.0610 (16) | −0.0059 (12) | 0.0092 (13) | 0.0018 (12) |
C6 | 0.0500 (15) | 0.0513 (12) | 0.0466 (13) | 0.0053 (11) | 0.0026 (12) | 0.0044 (11) |
C7 | 0.0597 (16) | 0.0413 (12) | 0.0587 (15) | −0.0011 (11) | −0.0027 (13) | −0.0043 (11) |
C8 | 0.0706 (19) | 0.0727 (17) | 0.0621 (17) | 0.0132 (15) | 0.0064 (15) | 0.0242 (14) |
O3 | 0.0722 (14) | 0.0901 (14) | 0.0873 (14) | −0.0270 (11) | −0.0280 (12) | 0.0159 (11) |
C9 | 0.0530 (16) | 0.0582 (14) | 0.0536 (15) | −0.0038 (12) | −0.0053 (13) | 0.0008 (12) |
C10 | 0.0554 (16) | 0.0719 (16) | 0.0537 (15) | 0.0039 (13) | −0.0019 (13) | 0.0093 (13) |
C11 | 0.0646 (18) | 0.0589 (15) | 0.0666 (17) | −0.0138 (13) | 0.0011 (15) | 0.0009 (13) |
C12 | 0.0640 (17) | 0.0497 (13) | 0.0683 (17) | −0.0035 (12) | 0.0051 (14) | 0.0063 (12) |
C13 | 0.0581 (16) | 0.0439 (12) | 0.0723 (17) | −0.0029 (11) | 0.0012 (14) | 0.0009 (12) |
C14 | 0.0568 (17) | 0.0703 (17) | 0.0622 (17) | −0.0111 (13) | −0.0008 (14) | −0.0147 (14) |
C15 | 0.0621 (18) | 0.0651 (16) | 0.0775 (19) | −0.0048 (14) | −0.0101 (15) | 0.0263 (14) |
C16 | 0.0658 (18) | 0.0550 (14) | 0.0615 (16) | 0.0045 (13) | 0.0187 (14) | 0.0104 (12) |
C17 | 0.0693 (18) | 0.0516 (14) | 0.0746 (18) | 0.0030 (13) | 0.0015 (15) | −0.0140 (13) |
C18 | 0.084 (2) | 0.099 (2) | 0.087 (2) | −0.0138 (18) | 0.0216 (19) | −0.0229 (18) |
C19 | 0.133 (3) | 0.0430 (14) | 0.124 (3) | 0.0074 (17) | 0.060 (3) | 0.0136 (16) |
C20 | 0.105 (2) | 0.0431 (14) | 0.107 (2) | 0.0176 (14) | 0.041 (2) | 0.0204 (14) |
C21 | 0.102 (3) | 0.078 (2) | 0.111 (3) | −0.0075 (18) | 0.027 (2) | 0.0322 (19) |
O2—C15 | 1.359 (3) | C10—H10 | 0.9300 |
O2—C6 | 1.376 (3) | C11—C13 | 1.364 (4) |
O1—C7 | 1.359 (3) | C11—C14 | 1.393 (3) |
O1—C19 | 1.390 (3) | C11—H11 | 0.9300 |
C1—C15 | 1.324 (3) | C12—C20 | 1.501 (4) |
C1—C9 | 1.459 (4) | C12—H12A | 0.9700 |
C1—C12 | 1.505 (3) | C12—H12B | 0.9700 |
C2—C7 | 1.395 (3) | C13—H13 | 0.9300 |
C2—C13 | 1.402 (3) | C14—C17 | 1.381 (4) |
C2—C4 | 1.451 (3) | C14—C18 | 1.505 (4) |
O4—C4 | 1.222 (3) | C15—H15 | 0.9300 |
C3—C6 | 1.379 (3) | C16—C21 | 1.508 (4) |
C3—C10 | 1.399 (3) | C17—H17 | 0.9300 |
C3—C9 | 1.460 (3) | C18—H18A | 0.9600 |
C4—C20 | 1.499 (3) | C18—H18B | 0.9600 |
C5—C16 | 1.373 (4) | C18—H18C | 0.9600 |
C5—C6 | 1.390 (3) | C19—C20 | 1.380 (4) |
C5—H5 | 0.9300 | C19—H19 | 0.9700 |
C7—C17 | 1.385 (3) | C19—H1 | 0.9700 |
C8—C10 | 1.367 (4) | C20—H20 | 0.9800 |
C8—C16 | 1.394 (4) | C21—H21A | 0.9600 |
C8—H8 | 0.9300 | C21—H21B | 0.9600 |
O3—C9 | 1.229 (3) | C21—H21C | 0.9600 |
C15—O2—C6 | 117.2 (2) | H12A—C12—H12B | 107.5 |
C7—O1—C19 | 116.44 (18) | C11—C13—C2 | 121.4 (2) |
C15—C1—C9 | 119.3 (2) | C11—C13—H13 | 119.3 |
C15—C1—C12 | 120.3 (2) | C2—C13—H13 | 119.3 |
C9—C1—C12 | 120.3 (2) | C17—C14—C11 | 117.9 (2) |
C7—C2—C13 | 117.4 (2) | C17—C14—C18 | 121.4 (3) |
C7—C2—C4 | 120.3 (2) | C11—C14—C18 | 120.8 (3) |
C13—C2—C4 | 122.3 (2) | C1—C15—O2 | 126.3 (2) |
C6—C3—C10 | 117.3 (2) | C1—C15—H15 | 116.8 |
C6—C3—C9 | 120.7 (2) | O2—C15—H15 | 116.8 |
C10—C3—C9 | 122.1 (2) | C5—C16—C8 | 118.5 (2) |
O4—C4—C2 | 123.2 (2) | C5—C16—C21 | 120.2 (3) |
O4—C4—C20 | 121.7 (2) | C8—C16—C21 | 121.3 (3) |
C2—C4—C20 | 115.07 (19) | C14—C17—C7 | 121.5 (2) |
C16—C5—C6 | 119.4 (3) | C14—C17—H17 | 119.3 |
C16—C5—H5 | 120.3 | C7—C17—H17 | 119.3 |
C6—C5—H5 | 120.3 | C14—C18—H18A | 109.5 |
O2—C6—C3 | 121.8 (2) | C14—C18—H18B | 109.5 |
O2—C6—C5 | 115.6 (2) | H18A—C18—H18B | 109.5 |
C3—C6—C5 | 122.7 (2) | C14—C18—H18C | 109.5 |
O1—C7—C17 | 116.9 (2) | H18A—C18—H18C | 109.5 |
O1—C7—C2 | 122.4 (2) | H18B—C18—H18C | 109.5 |
C17—C7—C2 | 120.6 (2) | C20—C19—O1 | 121.2 (3) |
C10—C8—C16 | 121.9 (2) | C20—C19—H19 | 107.0 |
C10—C8—H8 | 119.1 | O1—C19—H19 | 107.0 |
C16—C8—H8 | 119.1 | C20—C19—H1 | 107.0 |
O3—C9—C1 | 122.3 (2) | O1—C19—H1 | 107.0 |
O3—C9—C3 | 123.0 (2) | H19—C19—H1 | 106.8 |
C1—C9—C3 | 114.7 (2) | C19—C20—C4 | 114.7 (2) |
C8—C10—C3 | 120.3 (3) | C19—C20—C12 | 122.7 (3) |
C8—C10—H10 | 119.8 | C4—C20—C12 | 114.6 (2) |
C3—C10—H10 | 119.8 | C19—C20—H20 | 99.5 |
C13—C11—C14 | 121.2 (2) | C4—C20—H20 | 99.5 |
C13—C11—H11 | 119.4 | C12—C20—H20 | 99.5 |
C14—C11—H11 | 119.4 | C16—C21—H21A | 109.5 |
C20—C12—C1 | 114.9 (2) | C16—C21—H21B | 109.5 |
C20—C12—H12A | 108.5 | H21A—C21—H21B | 109.5 |
C1—C12—H12A | 108.5 | C16—C21—H21C | 109.5 |
C20—C12—H12B | 108.5 | H21A—C21—H21C | 109.5 |
C1—C12—H12B | 108.5 | H21B—C21—H21C | 109.5 |
C19—O1—C7—C2 | −11.4 (4) | C6—C3—C9—O3 | −179.2 (2) |
C19—O1—C7—C17 | 169.2 (3) | C6—C3—C9—C1 | 0.9 (3) |
C7—O1—C19—C20 | 33.0 (4) | C10—C3—C9—O3 | 1.1 (4) |
C15—O2—C6—C3 | −2.0 (3) | C10—C3—C9—C1 | −178.9 (2) |
C15—O2—C6—C5 | 178.0 (2) | C6—C3—C10—C8 | −0.5 (4) |
C6—O2—C15—C1 | 3.3 (4) | C9—C3—C10—C8 | 179.2 (2) |
C12—C1—C9—O3 | −1.4 (4) | O4—C4—C20—C12 | −10.6 (4) |
C12—C1—C9—C3 | 178.6 (2) | O4—C4—C20—C19 | −160.5 (3) |
C15—C1—C9—O3 | −179.8 (3) | C2—C4—C20—C12 | 172.1 (2) |
C15—C1—C9—C3 | 0.2 (3) | C2—C4—C20—C19 | 22.2 (4) |
C9—C1—C12—C20 | 87.7 (3) | C16—C5—C6—O2 | −179.1 (2) |
C15—C1—C12—C20 | −93.9 (3) | C16—C5—C6—C3 | 1.0 (4) |
C9—C1—C15—O2 | −2.4 (4) | C6—C5—C16—C8 | −0.9 (4) |
C12—C1—C15—O2 | 179.3 (2) | C6—C5—C16—C21 | 178.2 (2) |
C7—C2—C4—O4 | 179.2 (2) | O1—C7—C17—C14 | 179.0 (3) |
C7—C2—C4—C20 | −3.6 (3) | C2—C7—C17—C14 | −0.4 (4) |
C13—C2—C4—O4 | −3.1 (4) | C16—C8—C10—C3 | 0.5 (4) |
C13—C2—C4—C20 | 174.2 (2) | C10—C8—C16—C5 | 0.2 (4) |
C4—C2—C7—O1 | −2.0 (3) | C10—C8—C16—C21 | −178.9 (3) |
C4—C2—C7—C17 | 177.5 (2) | C14—C11—C13—C2 | −1.9 (4) |
C13—C2—C7—O1 | −179.8 (2) | C13—C11—C14—C17 | 1.1 (4) |
C13—C2—C7—C17 | −0.4 (3) | C13—C11—C14—C18 | −177.6 (3) |
C4—C2—C13—C11 | −176.3 (2) | C1—C12—C20—C4 | 175.3 (2) |
C7—C2—C13—C11 | 1.5 (4) | C1—C12—C20—C19 | −37.5 (4) |
C9—C3—C6—O2 | 0.1 (3) | C11—C14—C17—C7 | 0.1 (4) |
C9—C3—C6—C5 | −180.0 (2) | C18—C14—C17—C7 | 178.8 (3) |
C10—C3—C6—O2 | 179.8 (2) | O1—C19—C20—C4 | −38.2 (5) |
C10—C3—C6—C5 | −0.2 (3) | O1—C19—C20—C12 | 174.7 (3) |
Experimental details
Crystal data | |
Chemical formula | C21H18O4 |
Mr | 334.35 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 10.664 (2), 6.6428 (13), 23.754 (5) |
β (°) | 91.11 (3) |
V (Å3) | 1682.4 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.44 × 0.22 × 0.22 |
Data collection | |
Diffractometer | Bruker SMART CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2007) |
Tmin, Tmax | 0.961, 0.980 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11780, 4032, 1982 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.059, 0.180, 1.02 |
No. of reflections | 4032 |
No. of parameters | 229 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.43, −0.30 |
Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Acknowledgements
The authors are thankful to the University Grants Commission, New Delhi, India, for financial support in the form of a Major Research Project. In addition, they express thanks to Dr Srinivasulu and Dr Jai Anand Garg for their valuable support in the preparation of this structure report.
References
Ambartsumyan, A. A., Vasiléva, T. T., Chakhovskaya, O. V., Mysova, N. E., Tuskaev, V. A., Khrustalev, V. N. & Kochetkov, K. A. (2012). Russ. J. Org. Chem. 48, 451–455. Web of Science CrossRef CAS Google Scholar
Bruker (2007). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Dean, F. M. & Murray, S. (1975). J. Chem. Soc. Perkin Trans. 1, pp. 1706–1711. CrossRef Web of Science Google Scholar
Li, Y., Xiao, T., Liu, D. & Yu, G. (2010). Acta Cryst. E66, o694. Web of Science CSD CrossRef IUCr Journals Google Scholar
Nyburg, S. C., Prasad, L., Leong, T. S. & Still, I. W. J. (1986). Acta Cryst. C42, 816–821. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Panja, S. K., Maiti, S., Drew, M. G. B. & Bandyopadhyay, Ch. (2009). Tetrahedron, 65, 1276–1280. Web of Science CSD CrossRef CAS Google Scholar
Santhosh, K. C. & Balasubramanian, K. K. (1991). Tetrahedron Lett. 32, 7727–7730. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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The chromanone moiety forms an important component in pharmacophores in a number of biologically active molecules of synthetic as well as natural origin. Bis-chromanones bridged by a methylene group at C3 of the ring are considered to be a biologically important class of molecules (Santhosh & Balasubramanian, 1991; Panja, et al., 2009). Herein we report the structure of the racemic title compound, C21H18O4, in which the dihedral angle between the phenyl rings of the two chromanone moieties is 78.18 (12)° (Fig. 1). The chromone ring is essentially planar [maximum deviation from the l.s. plane = 0.026 (3) Å (C15)], while in the chromanone ring the maximum deviation is 0.206 (4) Å (C19)]. In the chromanone ring system, the C19—C20 bond length is short [1.380 (5)]. The torsion angles about the central methylene carbon C12 (C15—C1—C12—C20 and C19—C20—C12—C1) are -93.91 (3) and -37.48 (4)°, respectively. The angle subtended at C12 by the C—C bonds (C1—C12—C20) is 114.87 (2)°. The olefinic bond length [C1—C15 = 1.324 (4) Å] is close to the values found in known chromanone systems (Ambartsumyan et al., 2012). Some examples of bis-chromanone structures are known (Dean & Murray, 1975). In the crystal, there are weak π···π stacking interactions [minimum ring centroid separation = 3.9286 (17) Å].