


Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536809053586/cv2673sup1.cif |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S1600536809053586/cv2673Isup2.hkl |
CCDC reference: 766851
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean
(C-C) = 0.005 Å
- R factor = 0.088
- wR factor = 0.161
- Data-to-parameter ratio = 13.7
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT230_ALERT_2_C Hirshfeld Test Diff for C4 -- C5 .. 5.26 su PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C15 PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang .. 5 PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L= 0.595 32 PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given ....... ?
Alert level G PLAT154_ALERT_1_G The su's on the Cell Angles are Equal (x 10000) 3000 Deg. PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature 293 K
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
Uracil (0.56 g, 5 mmol) and anhydrous potassium carbonate (0.84 g, 6 mmol) were mixed in N,N-dimethylformamide (20 ml). A solution of 4-methyl-benzyl chloride (0.70 g, 5 mmol) in acetone (10 ml) was then added dropwise, with stirring, at room temperature, and the mixture was stirred for another 10 h and then refluxed for 4 h. The solvent was evaporated in vacuo and the residue was washed with water. The resulting white precipitate was filtered off and purified by column chromatography on silica gel (petroleum ether:ethyl acetate = 2:1). The title compound was recrystallized from ethanol and single crystals of (I) were obtained by slow evaporation.
All H atoms were placed in calculated positions, with C—H = 0.93 - 0.97 Å, and included in the final cycles of refinement using a riding model, with Uiso(H) = 1.2–1.5 Ueq(C).
Data collection: CrystalClear (Rigaku/MSC, 2006); cell refinement: CrystalClear (Rigaku/MSC, 2006); data reduction: CrystalClear (Rigaku/MSC, 2006); 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 structure of (I), with displacement ellipsoids drawn at the 30% probability level. H atoms omitted for clarity. |
C20H20N2O2 | Z = 2 |
Mr = 320.38 | F(000) = 340 |
Triclinic, P1 | Dx = 1.236 Mg m−3 |
a = 9.4182 (19) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.102 (2) Å | Cell parameters from 2459 reflections |
c = 10.448 (2) Å | θ = 2.1–27.9° |
α = 66.25 (3)° | µ = 0.08 mm−1 |
β = 80.79 (3)° | T = 293 K |
γ = 71.18 (3)° | Prism, colourless |
V = 860.7 (3) Å3 | 0.20 × 0.20 × 0.20 mm |
Rigaku Saturn CCD area-detector diffractometer | 3001 independent reflections |
Radiation source: fine-focus sealed tube | 2529 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
Detector resolution: 28.5714 pixels mm-1 | θmax = 25.0°, θmin = 2.1° |
phi and ω scans | h = −11→11 |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2006) | k = −11→12 |
Tmin = 0.984, Tmax = 0.984 | l = −12→12 |
8622 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.088 | H-atom parameters constrained |
wR(F2) = 0.161 | w = 1/[σ2(Fo2) + (0.0409P)2 + 0.3734P] where P = (Fo2 + 2Fc2)/3 |
S = 1.27 | (Δ/σ)max < 0.001 |
3001 reflections | Δρmax = 0.14 e Å−3 |
219 parameters | Δρmin = −0.17 e Å−3 |
Primary atom site location: structure-invariant direct methods |
C20H20N2O2 | γ = 71.18 (3)° |
Mr = 320.38 | V = 860.7 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 9.4182 (19) Å | Mo Kα radiation |
b = 10.102 (2) Å | µ = 0.08 mm−1 |
c = 10.448 (2) Å | T = 293 K |
α = 66.25 (3)° | 0.20 × 0.20 × 0.20 mm |
β = 80.79 (3)° |
Rigaku Saturn CCD area-detector diffractometer | 3001 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2006) | 2529 reflections with I > 2σ(I) |
Tmin = 0.984, Tmax = 0.984 | Rint = 0.034 |
8622 measured reflections |
R[F2 > 2σ(F2)] = 0.088 | 219 parameters |
wR(F2) = 0.161 | H-atom parameters constrained |
S = 1.27 | Δρmax = 0.14 e Å−3 |
3001 reflections | Δρmin = −0.17 e Å−3 |
Experimental. Software + citation |
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 | 0.4982 (3) | 0.1871 (3) | 0.6026 (3) | 0.0711 (7) | |
O2 | 0.3392 (2) | 0.4909 (3) | 0.8542 (2) | 0.0661 (7) | |
N1 | 0.4156 (2) | 0.3369 (3) | 0.7299 (2) | 0.0452 (6) | |
N2 | 0.2678 (3) | 0.5867 (3) | 0.6284 (3) | 0.0491 (6) | |
C1 | 0.3407 (3) | 0.4728 (3) | 0.7458 (3) | 0.0483 (7) | |
C2 | 0.6580 (3) | 0.1972 (3) | 0.8500 (3) | 0.0431 (7) | |
C3 | 0.1828 (3) | 0.7346 (3) | 0.6372 (4) | 0.0596 (9) | |
H3A | 0.1960 | 0.8147 | 0.5494 | 0.072* | |
H3B | 0.2227 | 0.7467 | 0.7105 | 0.072* | |
C4 | 0.3402 (3) | 0.4340 (4) | 0.4937 (3) | 0.0562 (8) | |
H4 | 0.3370 | 0.4235 | 0.4099 | 0.067* | |
C5 | 0.2677 (3) | 0.5635 (4) | 0.5079 (3) | 0.0543 (8) | |
H5 | 0.2143 | 0.6422 | 0.4330 | 0.065* | |
C6 | 0.7652 (3) | 0.0843 (3) | 0.8165 (3) | 0.0529 (8) | |
H6 | 0.7358 | 0.0149 | 0.7973 | 0.064* | |
C7 | 0.4931 (3) | 0.2105 (3) | 0.8525 (3) | 0.0521 (8) | |
H7A | 0.4827 | 0.1170 | 0.8550 | 0.063* | |
H7B | 0.4451 | 0.2249 | 0.9372 | 0.063* | |
C8 | −0.2911 (3) | 0.7765 (3) | 0.7206 (3) | 0.0492 (8) | |
C9 | 0.4242 (3) | 0.3092 (4) | 0.6070 (3) | 0.0526 (8) | |
C10 | −0.0848 (4) | 0.8346 (4) | 0.5629 (3) | 0.0577 (8) | |
H10 | −0.0510 | 0.8844 | 0.4730 | 0.069* | |
C11 | 0.0171 (3) | 0.7490 (3) | 0.6673 (3) | 0.0473 (7) | |
C12 | 0.9150 (4) | 0.0739 (4) | 0.8113 (3) | 0.0614 (9) | |
H12 | 0.9854 | −0.0040 | 0.7901 | 0.074* | |
C13 | −0.0374 (4) | 0.6768 (4) | 0.7999 (3) | 0.0599 (9) | |
H13 | 0.0286 | 0.6189 | 0.8726 | 0.072* | |
C14 | −0.1891 (4) | 0.6899 (3) | 0.8254 (3) | 0.0582 (9) | |
H14 | −0.2231 | 0.6392 | 0.9150 | 0.070* | |
C15 | 0.9639 (4) | 0.1749 (4) | 0.8365 (3) | 0.0630 (10) | |
C16 | −0.4572 (3) | 0.7930 (4) | 0.7502 (4) | 0.0696 (10) | |
H16A | −0.5029 | 0.8770 | 0.7787 | 0.104* | |
H16B | −0.4712 | 0.7025 | 0.8235 | 0.104* | |
H16C | −0.5030 | 0.8099 | 0.6671 | 0.104* | |
C17 | 0.7049 (4) | 0.2967 (4) | 0.8803 (3) | 0.0601 (9) | |
H17 | 0.6349 | 0.3714 | 0.9064 | 0.072* | |
C18 | −0.2361 (4) | 0.8480 (4) | 0.5894 (4) | 0.0610 (9) | |
H18 | −0.3022 | 0.9066 | 0.5168 | 0.073* | |
C19 | 0.8569 (4) | 0.2856 (4) | 0.8720 (4) | 0.0717 (11) | |
H19 | 0.8869 | 0.3548 | 0.8909 | 0.086* | |
C20 | 1.1291 (4) | 0.1673 (6) | 0.8239 (4) | 0.1041 (16) | |
H20A | 1.1884 | 0.0636 | 0.8601 | 0.156* | |
H20B | 1.1462 | 0.2195 | 0.8764 | 0.156* | |
H20C | 1.1572 | 0.2137 | 0.7274 | 0.156* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0713 (16) | 0.0577 (15) | 0.0837 (18) | −0.0011 (12) | −0.0192 (13) | −0.0334 (13) |
O2 | 0.0646 (15) | 0.0773 (16) | 0.0552 (14) | −0.0105 (12) | −0.0044 (11) | −0.0303 (13) |
N1 | 0.0379 (13) | 0.0480 (15) | 0.0434 (14) | −0.0112 (11) | −0.0041 (11) | −0.0106 (12) |
N2 | 0.0424 (14) | 0.0438 (14) | 0.0534 (16) | −0.0082 (11) | −0.0015 (12) | −0.0138 (12) |
C1 | 0.0381 (17) | 0.0513 (19) | 0.052 (2) | −0.0148 (14) | 0.0023 (14) | −0.0162 (16) |
C2 | 0.0462 (17) | 0.0411 (16) | 0.0355 (15) | −0.0103 (14) | −0.0092 (13) | −0.0066 (13) |
C3 | 0.0519 (19) | 0.0480 (19) | 0.076 (2) | −0.0136 (16) | 0.0004 (16) | −0.0216 (17) |
C4 | 0.053 (2) | 0.057 (2) | 0.058 (2) | −0.0112 (17) | −0.0080 (16) | −0.0218 (17) |
C5 | 0.0481 (19) | 0.058 (2) | 0.0452 (19) | −0.0149 (16) | −0.0077 (14) | −0.0052 (16) |
C6 | 0.055 (2) | 0.0476 (18) | 0.0524 (19) | −0.0145 (15) | −0.0082 (15) | −0.0126 (15) |
C7 | 0.0487 (18) | 0.0488 (18) | 0.0469 (18) | −0.0157 (15) | −0.0059 (14) | −0.0032 (14) |
C8 | 0.0509 (19) | 0.0464 (18) | 0.0543 (19) | −0.0124 (15) | 0.0041 (15) | −0.0262 (15) |
C9 | 0.0415 (18) | 0.054 (2) | 0.062 (2) | −0.0143 (16) | −0.0056 (15) | −0.0203 (17) |
C10 | 0.059 (2) | 0.056 (2) | 0.0474 (19) | −0.0160 (16) | 0.0000 (15) | −0.0094 (16) |
C11 | 0.0463 (17) | 0.0376 (16) | 0.0568 (19) | −0.0090 (14) | −0.0008 (15) | −0.0192 (14) |
C12 | 0.052 (2) | 0.060 (2) | 0.054 (2) | −0.0038 (17) | −0.0051 (16) | −0.0103 (17) |
C13 | 0.056 (2) | 0.060 (2) | 0.0489 (19) | −0.0025 (16) | −0.0081 (16) | −0.0143 (16) |
C14 | 0.060 (2) | 0.054 (2) | 0.0499 (19) | −0.0094 (17) | 0.0092 (16) | −0.0181 (16) |
C15 | 0.050 (2) | 0.073 (2) | 0.047 (2) | −0.0214 (19) | −0.0100 (15) | 0.0015 (17) |
C16 | 0.053 (2) | 0.081 (3) | 0.083 (3) | −0.0202 (18) | 0.0078 (18) | −0.042 (2) |
C17 | 0.058 (2) | 0.056 (2) | 0.068 (2) | −0.0105 (17) | −0.0118 (17) | −0.0254 (17) |
C18 | 0.051 (2) | 0.070 (2) | 0.057 (2) | −0.0112 (17) | −0.0121 (16) | −0.0191 (18) |
C19 | 0.075 (3) | 0.072 (2) | 0.079 (3) | −0.034 (2) | −0.024 (2) | −0.021 (2) |
C20 | 0.055 (2) | 0.149 (4) | 0.084 (3) | −0.042 (3) | −0.010 (2) | −0.007 (3) |
O1—C9 | 1.221 (4) | C8—C14 | 1.382 (4) |
O2—C1 | 1.215 (3) | C8—C16 | 1.513 (4) |
N1—C1 | 1.390 (4) | C10—C18 | 1.381 (4) |
N1—C9 | 1.405 (4) | C10—C11 | 1.378 (4) |
N1—C7 | 1.478 (3) | C10—H10 | 0.9300 |
N2—C5 | 1.370 (4) | C11—C13 | 1.383 (4) |
N2—C1 | 1.386 (4) | C12—C15 | 1.371 (5) |
N2—C3 | 1.482 (4) | C12—H12 | 0.9300 |
C2—C17 | 1.376 (4) | C13—C14 | 1.383 (4) |
C2—C6 | 1.381 (4) | C13—H13 | 0.9300 |
C2—C7 | 1.512 (4) | C14—H14 | 0.9300 |
C3—C11 | 1.512 (4) | C15—C19 | 1.375 (5) |
C3—H3A | 0.9700 | C15—C20 | 1.520 (4) |
C3—H3B | 0.9700 | C16—H16A | 0.9600 |
C4—C5 | 1.322 (4) | C16—H16B | 0.9600 |
C4—C9 | 1.439 (4) | C16—H16C | 0.9600 |
C4—H4 | 0.9300 | C17—C19 | 1.391 (4) |
C5—H5 | 0.9300 | C17—H17 | 0.9300 |
C6—C12 | 1.375 (4) | C18—H18 | 0.9300 |
C6—H6 | 0.9300 | C19—H19 | 0.9300 |
C7—H7A | 0.9700 | C20—H20A | 0.9600 |
C7—H7B | 0.9700 | C20—H20B | 0.9600 |
C8—C18 | 1.374 (4) | C20—H20C | 0.9600 |
C1—N1—C9 | 125.6 (3) | C18—C10—C11 | 121.3 (3) |
C1—N1—C7 | 117.3 (3) | C18—C10—H10 | 119.4 |
C9—N1—C7 | 117.1 (3) | C11—C10—H10 | 119.4 |
C5—N2—C1 | 121.7 (3) | C10—C11—C13 | 117.7 (3) |
C5—N2—C3 | 119.8 (3) | C10—C11—C3 | 120.8 (3) |
C1—N2—C3 | 118.5 (3) | C13—C11—C3 | 121.5 (3) |
O2—C1—N2 | 122.4 (3) | C6—C12—C15 | 122.0 (3) |
O2—C1—N1 | 122.7 (3) | C6—C12—H12 | 119.0 |
N2—C1—N1 | 114.9 (3) | C15—C12—H12 | 119.0 |
C17—C2—C6 | 118.5 (3) | C14—C13—C11 | 120.7 (3) |
C17—C2—C7 | 121.2 (3) | C14—C13—H13 | 119.6 |
C6—C2—C7 | 120.3 (3) | C11—C13—H13 | 119.6 |
N2—C3—C11 | 111.9 (2) | C8—C14—C13 | 121.5 (3) |
N2—C3—H3A | 109.2 | C8—C14—H14 | 119.3 |
C11—C3—H3A | 109.2 | C13—C14—H14 | 119.3 |
N2—C3—H3B | 109.2 | C12—C15—C19 | 117.3 (3) |
C11—C3—H3B | 109.2 | C12—C15—C20 | 121.7 (4) |
H3A—C3—H3B | 107.9 | C19—C15—C20 | 120.9 (4) |
C5—C4—C9 | 120.5 (3) | C8—C16—H16A | 109.5 |
C5—C4—H4 | 119.8 | C8—C16—H16B | 109.5 |
C9—C4—H4 | 119.8 | H16A—C16—H16B | 109.5 |
C4—C5—N2 | 122.8 (3) | C8—C16—H16C | 109.5 |
C4—C5—H5 | 118.6 | H16A—C16—H16C | 109.5 |
N2—C5—H5 | 118.6 | H16B—C16—H16C | 109.5 |
C12—C6—C2 | 120.5 (3) | C2—C17—C19 | 120.1 (3) |
C12—C6—H6 | 119.8 | C2—C17—H17 | 120.0 |
C2—C6—H6 | 119.8 | C19—C17—H17 | 120.0 |
N1—C7—C2 | 112.6 (2) | C10—C18—C8 | 121.4 (3) |
N1—C7—H7A | 109.1 | C10—C18—H18 | 119.3 |
C2—C7—H7A | 109.1 | C8—C18—H18 | 119.3 |
N1—C7—H7B | 109.1 | C15—C19—C17 | 121.6 (3) |
C2—C7—H7B | 109.1 | C15—C19—H19 | 119.2 |
H7A—C7—H7B | 107.8 | C17—C19—H19 | 119.2 |
C18—C8—C14 | 117.5 (3) | C15—C20—H20A | 109.5 |
C18—C8—C16 | 121.4 (3) | C15—C20—H20B | 109.5 |
C14—C8—C16 | 121.1 (3) | H20A—C20—H20B | 109.5 |
O1—C9—N1 | 120.2 (3) | C15—C20—H20C | 109.5 |
O1—C9—C4 | 125.3 (3) | H20A—C20—H20C | 109.5 |
N1—C9—C4 | 114.4 (3) | H20B—C20—H20C | 109.5 |
C5—N2—C1—O2 | −178.4 (3) | C5—C4—C9—O1 | −177.7 (3) |
C3—N2—C1—O2 | −1.2 (4) | C5—C4—C9—N1 | 2.5 (4) |
C5—N2—C1—N1 | 1.6 (4) | C18—C10—C11—C13 | −0.1 (5) |
C3—N2—C1—N1 | 178.9 (2) | C18—C10—C11—C3 | 179.8 (3) |
C9—N1—C1—O2 | −178.8 (3) | N2—C3—C11—C10 | −103.7 (3) |
C7—N1—C1—O2 | 1.1 (4) | N2—C3—C11—C13 | 76.1 (4) |
C9—N1—C1—N2 | 1.2 (4) | C2—C6—C12—C15 | −1.1 (5) |
C7—N1—C1—N2 | −178.9 (2) | C10—C11—C13—C14 | 0.5 (5) |
C5—N2—C3—C11 | 80.2 (3) | C3—C11—C13—C14 | −179.3 (3) |
C1—N2—C3—C11 | −97.2 (3) | C18—C8—C14—C13 | 0.8 (5) |
C9—C4—C5—N2 | 0.0 (5) | C16—C8—C14—C13 | −178.6 (3) |
C1—N2—C5—C4 | −2.2 (4) | C11—C13—C14—C8 | −0.9 (5) |
C3—N2—C5—C4 | −179.5 (3) | C6—C12—C15—C19 | 2.1 (5) |
C17—C2—C6—C12 | −1.1 (4) | C6—C12—C15—C20 | −177.1 (3) |
C7—C2—C6—C12 | 178.7 (3) | C6—C2—C17—C19 | 2.3 (5) |
C1—N1—C7—C2 | −95.8 (3) | C7—C2—C17—C19 | −177.5 (3) |
C9—N1—C7—C2 | 84.1 (3) | C11—C10—C18—C8 | 0.0 (5) |
C17—C2—C7—N1 | 74.8 (4) | C14—C8—C18—C10 | −0.3 (5) |
C6—C2—C7—N1 | −105.0 (3) | C16—C8—C18—C10 | 179.0 (3) |
C1—N1—C9—O1 | 177.0 (3) | C12—C15—C19—C17 | −0.9 (5) |
C7—N1—C9—O1 | −2.8 (4) | C20—C15—C19—C17 | 178.3 (3) |
C1—N1—C9—C4 | −3.2 (4) | C2—C17—C19—C15 | −1.3 (5) |
C7—N1—C9—C4 | 176.9 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C14—H14···O2i | 0.93 | 2.50 | 3.430 (4) | 174 |
Symmetry code: (i) −x, −y+1, −z+2. |
Experimental details
Crystal data | |
Chemical formula | C20H20N2O2 |
Mr | 320.38 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 9.4182 (19), 10.102 (2), 10.448 (2) |
α, β, γ (°) | 66.25 (3), 80.79 (3), 71.18 (3) |
V (Å3) | 860.7 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.20 × 0.20 × 0.20 |
Data collection | |
Diffractometer | Rigaku Saturn CCD area-detector diffractometer |
Absorption correction | Multi-scan (CrystalClear; Rigaku/MSC, 2006) |
Tmin, Tmax | 0.984, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8622, 3001, 2529 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.088, 0.161, 1.27 |
No. of reflections | 3001 |
No. of parameters | 219 |
No. of restraints | ? |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.14, −0.17 |
Computer programs: CrystalClear (Rigaku/MSC, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C14—H14···O2i | 0.93 | 2.50 | 3.430 (4) | 174.3 |
Symmetry code: (i) −x, −y+1, −z+2. |
In continuation of our search for new biologically active pyrimidine derivatives (Yang & Li, 2006), we present here the title compound (I).
In (I) (Fig. 1), all bond lengths and angles are normal and correspond to those observed in the related 1,3-bis(4-chlorobenzyl)pyrimidine-2,4(1H,3H)-dione (Yang & Li, 2006). The central pyrimidine ring forms dihedral angles of 71.9 (1)° and 69.8 (1)° with the two benzene rings, respectively. Weak intermolecular C—H···O hydrogen bonds (Table 1) link molecules into centrosymmetric dimers. The crystal packing exhibits also π-π interactions proved by short distances of 3.674 (2) Å between the centroids of pyrimidine rings from the neighbouring molecules.