organic compounds
6-Amino-1,3-dimethyl-5-[(E)-2-(methylsulfanyl)benzylideneamino]pyrimidine-2,4(1H,3H)-dione
aUniversity of Kwazulu-Natal, School of Chemistry, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa, and bNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth 6031, South Africa
*Correspondence e-mail: richard.betz@webmail.co.za
The title compound, C14H16N4O2S, is a Schiff base derivative of 2-(methylsulfanyl)benzaldehyde. The configuration about the C=N double bond is E. The heterocyclic ring is essentially planar (τ = 3.1°) and makes a dihedral angle of 12.24 (7)° with the benzene ring. An intramolecular N—H⋯S hydrogen bond is observed. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds link molecules into layers perpendicular to [101]. The closest distance between the centroids of two heterocyclic rings was found to be 3.5268 (8) Å.
Related literature
For background on chelating ligands, see: Gade (1998). For the crystal structures of other derived from ortho-(thiomethyl)benzaldehyde, see: Yan et al. (2007); Baidina et al. (1987). For details of graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995). For details of puckering analysis, see: Cremer & Pople (1975).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: APEX2 (Bruker, 2010); cell SAINT (Bruker, 2010); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536811020903/wn2434sup1.cif
contains datablocks I, global. DOI:Supporting information file. DOI: 10.1107/S1600536811020903/wn2434Isup2.cdx
Structure factors: contains datablock I. DOI: 10.1107/S1600536811020903/wn2434Isup3.hkl
Supporting information file. DOI: 10.1107/S1600536811020903/wn2434Isup4.cml
Equimolar amounts of ortho-(thiomethyl)-benzaldehyde (1.00 g, 6.57 mmol) and 5,6-diamino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione (1.12 g) in 50 cm3 anhydrous methanol were refluxed for three hours. The reaction mixture was allowed to cool to room temperature. A yellow precipitate was isolated which was recrystallized from anhydrous acetonitrile to give yellow crystals, which were suitable for X-ray analysis.
H atoms bonded to Csp2 atoms were placed in calculated positions (C—H 0.95 Å) and were included in the
in the riding model approximation, with U(H) set to 1.2Ueq(C). The H atoms of the methyl groups were allowed to rotate with a fixed angle around the C—C bond to best fit the experimental electron density (HFIX 137 in the SHELX program suite (Sheldrick, 2008)), with U(H) set to 1.5Ueq(C) and C—H = 0.98 Å. Both nitrogen-bound H atoms were located in a difference Fourier map and refined freely [N—H = 0.86 (2) Å and 0.88 (2) Å].Data collection: APEX2 (Bruker, 2010); cell
SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).C14H16N4O2S | F(000) = 640 |
Mr = 304.37 | Dx = 1.459 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -P 2ybc | Cell parameters from 6560 reflections |
a = 7.9740 (2) Å | θ = 2.6–28.3° |
b = 12.4630 (3) Å | µ = 0.24 mm−1 |
c = 13.9870 (3) Å | T = 100 K |
β = 94.384 (1)° | Rod, yellow |
V = 1385.96 (6) Å3 | 0.45 × 0.25 × 0.13 mm |
Z = 4 |
Bruker APEXII CCD diffractometer | 2912 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.025 |
Graphite monochromator | θmax = 28.3°, θmin = 2.2° |
ϕ and ω scans | h = −10→10 |
13383 measured reflections | k = −16→16 |
3441 independent reflections | l = −17→18 |
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)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.094 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | w = 1/[σ2(Fo2) + (0.042P)2 + 0.7103P] where P = (Fo2 + 2Fc2)/3 |
3441 reflections | (Δ/σ)max < 0.001 |
201 parameters | Δρmax = 0.43 e Å−3 |
0 restraints | Δρmin = −0.26 e Å−3 |
C14H16N4O2S | V = 1385.96 (6) Å3 |
Mr = 304.37 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.9740 (2) Å | µ = 0.24 mm−1 |
b = 12.4630 (3) Å | T = 100 K |
c = 13.9870 (3) Å | 0.45 × 0.25 × 0.13 mm |
β = 94.384 (1)° |
Bruker APEXII CCD diffractometer | 2912 reflections with I > 2σ(I) |
13383 measured reflections | Rint = 0.025 |
3441 independent reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.094 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | Δρmax = 0.43 e Å−3 |
3441 reflections | Δρmin = −0.26 e Å−3 |
201 parameters |
x | y | z | Uiso*/Ueq | ||
S1 | 0.24479 (5) | 0.11449 (3) | 0.01927 (3) | 0.01828 (10) | |
O1 | 0.20013 (13) | 0.57346 (8) | 0.04281 (7) | 0.0182 (2) | |
O2 | 0.45091 (14) | 0.64532 (9) | −0.23229 (8) | 0.0219 (2) | |
N1 | 0.32410 (15) | 0.60885 (9) | −0.09573 (8) | 0.0145 (2) | |
N2 | 0.45428 (15) | 0.47261 (10) | −0.17925 (8) | 0.0151 (2) | |
N3 | 0.26375 (15) | 0.34072 (10) | 0.01660 (8) | 0.0141 (2) | |
N4 | 0.43846 (16) | 0.29401 (11) | −0.13145 (9) | 0.0179 (3) | |
H741 | 0.392 (3) | 0.2487 (17) | −0.0927 (14) | 0.027 (5)* | |
H742 | 0.480 (3) | 0.2713 (18) | −0.1826 (16) | 0.039 (6)* | |
C1 | 0.31118 (17) | 0.42673 (11) | −0.03962 (9) | 0.0133 (3) | |
C2 | 0.27303 (17) | 0.53685 (11) | −0.02460 (10) | 0.0131 (3) | |
C3 | 0.41138 (17) | 0.58028 (12) | −0.17251 (10) | 0.0155 (3) | |
C4 | 0.40082 (17) | 0.39688 (11) | −0.11738 (10) | 0.0142 (3) | |
C5 | 0.19312 (18) | 0.35231 (11) | 0.09502 (10) | 0.0164 (3) | |
H5 | 0.1728 | 0.4229 | 0.1171 | 0.020* | |
C6 | 0.14235 (18) | 0.26118 (12) | 0.15205 (10) | 0.0148 (3) | |
C7 | 0.15496 (18) | 0.15166 (12) | 0.12645 (10) | 0.0155 (3) | |
C8 | 0.09458 (18) | 0.07399 (12) | 0.18772 (11) | 0.0187 (3) | |
H8 | 0.1007 | 0.0003 | 0.1709 | 0.022* | |
C9 | 0.02593 (19) | 0.10237 (13) | 0.27252 (11) | 0.0203 (3) | |
H9 | −0.0145 | 0.0482 | 0.3126 | 0.024* | |
C10 | 0.01599 (19) | 0.20918 (13) | 0.29904 (11) | 0.0201 (3) | |
H10 | −0.0300 | 0.2284 | 0.3573 | 0.024* | |
C11 | 0.07393 (17) | 0.28749 (12) | 0.23952 (10) | 0.0151 (3) | |
H11 | 0.0676 | 0.3607 | 0.2579 | 0.018* | |
C12 | 0.2959 (2) | 0.72400 (11) | −0.08308 (11) | 0.0193 (3) | |
H121 | 0.4043 | 0.7604 | −0.0708 | 0.029* | |
H122 | 0.2275 | 0.7352 | −0.0286 | 0.029* | |
H123 | 0.2370 | 0.7534 | −0.1413 | 0.029* | |
C13 | 0.55971 (19) | 0.44007 (13) | −0.25572 (10) | 0.0203 (3) | |
H131 | 0.6549 | 0.3976 | −0.2282 | 0.030* | |
H132 | 0.6017 | 0.5041 | −0.2869 | 0.030* | |
H133 | 0.4929 | 0.3968 | −0.3032 | 0.030* | |
C14 | 0.2462 (2) | −0.03061 (12) | 0.02441 (12) | 0.0259 (3) | |
H141 | 0.3075 | −0.0541 | 0.0842 | 0.039* | |
H142 | 0.3016 | −0.0591 | −0.0304 | 0.039* | |
H143 | 0.1303 | −0.0572 | 0.0222 | 0.039* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0251 (2) | 0.01325 (17) | 0.01737 (18) | −0.00195 (13) | 0.00745 (13) | −0.00143 (13) |
O1 | 0.0237 (5) | 0.0156 (5) | 0.0163 (5) | 0.0005 (4) | 0.0081 (4) | −0.0011 (4) |
O2 | 0.0257 (6) | 0.0225 (6) | 0.0184 (5) | −0.0023 (4) | 0.0070 (4) | 0.0074 (4) |
N1 | 0.0171 (6) | 0.0121 (6) | 0.0145 (5) | −0.0006 (4) | 0.0034 (4) | 0.0017 (4) |
N2 | 0.0155 (6) | 0.0186 (6) | 0.0120 (5) | −0.0005 (5) | 0.0056 (4) | −0.0005 (4) |
N3 | 0.0153 (6) | 0.0126 (6) | 0.0147 (6) | −0.0011 (4) | 0.0016 (4) | 0.0001 (4) |
N4 | 0.0217 (6) | 0.0167 (6) | 0.0161 (6) | 0.0006 (5) | 0.0079 (5) | −0.0031 (5) |
C1 | 0.0154 (6) | 0.0117 (6) | 0.0130 (6) | −0.0011 (5) | 0.0027 (5) | −0.0003 (5) |
C2 | 0.0142 (6) | 0.0128 (6) | 0.0125 (6) | −0.0016 (5) | 0.0018 (5) | 0.0005 (5) |
C3 | 0.0145 (6) | 0.0186 (7) | 0.0134 (6) | −0.0017 (5) | 0.0016 (5) | 0.0018 (5) |
C4 | 0.0141 (6) | 0.0149 (7) | 0.0135 (6) | −0.0015 (5) | 0.0007 (5) | −0.0013 (5) |
C5 | 0.0194 (7) | 0.0130 (6) | 0.0174 (7) | 0.0008 (5) | 0.0046 (5) | 0.0000 (5) |
C6 | 0.0144 (7) | 0.0160 (7) | 0.0143 (6) | −0.0002 (5) | 0.0034 (5) | 0.0007 (5) |
C7 | 0.0148 (6) | 0.0166 (7) | 0.0151 (6) | −0.0012 (5) | 0.0025 (5) | 0.0012 (5) |
C8 | 0.0196 (7) | 0.0159 (7) | 0.0207 (7) | −0.0034 (5) | 0.0029 (6) | 0.0032 (6) |
C9 | 0.0187 (7) | 0.0234 (8) | 0.0192 (7) | −0.0042 (6) | 0.0039 (6) | 0.0072 (6) |
C10 | 0.0184 (7) | 0.0262 (8) | 0.0162 (7) | −0.0009 (6) | 0.0052 (5) | 0.0031 (6) |
C11 | 0.0161 (7) | 0.0162 (7) | 0.0136 (6) | 0.0006 (5) | 0.0058 (5) | 0.0016 (5) |
C12 | 0.0239 (8) | 0.0114 (6) | 0.0228 (7) | 0.0009 (5) | 0.0030 (6) | 0.0028 (5) |
C13 | 0.0209 (7) | 0.0253 (8) | 0.0160 (7) | −0.0004 (6) | 0.0103 (6) | −0.0009 (6) |
C14 | 0.0373 (9) | 0.0130 (7) | 0.0284 (8) | −0.0009 (6) | 0.0095 (7) | −0.0030 (6) |
S1—C7 | 1.7719 (15) | C6—C11 | 1.4157 (19) |
S1—C14 | 1.8098 (16) | C6—C7 | 1.417 (2) |
O1—C2 | 1.2325 (17) | C7—C8 | 1.402 (2) |
O2—C3 | 1.2231 (17) | C8—C9 | 1.390 (2) |
N1—C3 | 1.3706 (18) | C8—H8 | 0.9500 |
N1—C2 | 1.4223 (17) | C9—C10 | 1.386 (2) |
N1—C12 | 1.4655 (18) | C9—H9 | 0.9500 |
N2—C4 | 1.3702 (18) | C10—C11 | 1.385 (2) |
N2—C3 | 1.3897 (19) | C10—H10 | 0.9500 |
N2—C13 | 1.4672 (17) | C11—H11 | 0.9500 |
N3—C5 | 1.2789 (18) | C12—H121 | 0.9800 |
N3—C1 | 1.3986 (18) | C12—H122 | 0.9800 |
N4—C4 | 1.3348 (19) | C12—H123 | 0.9800 |
N4—H741 | 0.88 (2) | C13—H131 | 0.9800 |
N4—H742 | 0.86 (2) | C13—H132 | 0.9800 |
C1—C4 | 1.3968 (19) | C13—H133 | 0.9800 |
C1—C2 | 1.4247 (19) | C14—H141 | 0.9800 |
C5—C6 | 1.463 (2) | C14—H142 | 0.9800 |
C5—H5 | 0.9500 | C14—H143 | 0.9800 |
C7—S1—C14 | 103.25 (7) | C6—C7—S1 | 120.46 (11) |
C3—N1—C2 | 125.02 (12) | C9—C8—C7 | 121.47 (14) |
C3—N1—C12 | 116.16 (12) | C9—C8—H8 | 119.3 |
C2—N1—C12 | 118.59 (11) | C7—C8—H8 | 119.3 |
C4—N2—C3 | 122.15 (12) | C10—C9—C8 | 120.49 (14) |
C4—N2—C13 | 119.56 (12) | C10—C9—H9 | 119.8 |
C3—N2—C13 | 118.29 (12) | C8—C9—H9 | 119.8 |
C5—N3—C1 | 123.47 (13) | C11—C10—C9 | 119.18 (14) |
C4—N4—H741 | 114.4 (13) | C11—C10—H10 | 120.4 |
C4—N4—H742 | 123.0 (15) | C9—C10—H10 | 120.4 |
H741—N4—H742 | 120 (2) | C10—C11—C6 | 121.64 (14) |
C4—C1—N3 | 114.22 (12) | C10—C11—H11 | 119.2 |
C4—C1—C2 | 119.94 (12) | C6—C11—H11 | 119.2 |
N3—C1—C2 | 125.83 (12) | N1—C12—H121 | 109.5 |
O1—C2—N1 | 118.60 (12) | N1—C12—H122 | 109.5 |
O1—C2—C1 | 126.01 (13) | H121—C12—H122 | 109.5 |
N1—C2—C1 | 115.39 (12) | N1—C12—H123 | 109.5 |
O2—C3—N1 | 122.42 (14) | H121—C12—H123 | 109.5 |
O2—C3—N2 | 121.06 (13) | H122—C12—H123 | 109.5 |
N1—C3—N2 | 116.51 (12) | N2—C13—H131 | 109.5 |
N4—C4—N2 | 118.96 (13) | N2—C13—H132 | 109.5 |
N4—C4—C1 | 120.31 (13) | H131—C13—H132 | 109.5 |
N2—C4—C1 | 120.71 (13) | N2—C13—H133 | 109.5 |
N3—C5—C6 | 122.58 (13) | H131—C13—H133 | 109.5 |
N3—C5—H5 | 118.7 | H132—C13—H133 | 109.5 |
C6—C5—H5 | 118.7 | S1—C14—H141 | 109.5 |
C11—C6—C7 | 118.76 (13) | S1—C14—H142 | 109.5 |
C11—C6—C5 | 115.63 (13) | H141—C14—H142 | 109.5 |
C7—C6—C5 | 125.61 (13) | S1—C14—H143 | 109.5 |
C8—C7—C6 | 118.44 (13) | H141—C14—H143 | 109.5 |
C8—C7—S1 | 121.10 (12) | H142—C14—H143 | 109.5 |
C5—N3—C1—C4 | 174.13 (13) | C13—N2—C4—C1 | 175.11 (13) |
C5—N3—C1—C2 | −7.2 (2) | N3—C1—C4—N4 | −1.84 (19) |
C3—N1—C2—O1 | 177.49 (13) | C2—C1—C4—N4 | 179.37 (13) |
C12—N1—C2—O1 | 3.22 (19) | N3—C1—C4—N2 | 179.44 (12) |
C3—N1—C2—C1 | −3.08 (19) | C2—C1—C4—N2 | 0.6 (2) |
C12—N1—C2—C1 | −177.34 (12) | C1—N3—C5—C6 | 179.11 (13) |
C4—C1—C2—O1 | −177.39 (14) | N3—C5—C6—C11 | 176.78 (13) |
N3—C1—C2—O1 | 4.0 (2) | N3—C5—C6—C7 | −3.8 (2) |
C4—C1—C2—N1 | 3.22 (19) | C11—C6—C7—C8 | 1.8 (2) |
N3—C1—C2—N1 | −175.42 (12) | C5—C6—C7—C8 | −177.64 (14) |
C2—N1—C3—O2 | 179.26 (13) | C11—C6—C7—S1 | −178.33 (11) |
C12—N1—C3—O2 | −6.3 (2) | C5—C6—C7—S1 | 2.3 (2) |
C2—N1—C3—N2 | −1.0 (2) | C14—S1—C7—C8 | −4.30 (14) |
C12—N1—C3—N2 | 173.35 (12) | C14—S1—C7—C6 | 175.81 (12) |
C4—N2—C3—O2 | −175.03 (13) | C6—C7—C8—C9 | −1.0 (2) |
C13—N2—C3—O2 | 4.7 (2) | S1—C7—C8—C9 | 179.16 (11) |
C4—N2—C3—N1 | 5.27 (19) | C7—C8—C9—C10 | −0.3 (2) |
C13—N2—C3—N1 | −175.01 (12) | C8—C9—C10—C11 | 0.6 (2) |
C3—N2—C4—N4 | 176.08 (13) | C9—C10—C11—C6 | 0.3 (2) |
C13—N2—C4—N4 | −3.6 (2) | C7—C6—C11—C10 | −1.5 (2) |
C3—N2—C4—C1 | −5.2 (2) | C5—C6—C11—C10 | 177.98 (13) |
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H741···S1 | 0.88 (2) | 2.63 (2) | 3.5117 (14) | 178.4 (17) |
N4—H742···O2i | 0.86 (2) | 2.07 (2) | 2.8463 (16) | 150 (2) |
C9—H9···O1ii | 0.95 | 2.61 | 3.2807 (18) | 128 |
Symmetry codes: (i) −x+1, y−1/2, −z−1/2; (ii) −x, y−1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C14H16N4O2S |
Mr | 304.37 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 7.9740 (2), 12.4630 (3), 13.9870 (3) |
β (°) | 94.384 (1) |
V (Å3) | 1385.96 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.24 |
Crystal size (mm) | 0.45 × 0.25 × 0.13 |
Data collection | |
Diffractometer | Bruker APEXII CCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13383, 3441, 2912 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.668 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.094, 1.09 |
No. of reflections | 3441 |
No. of parameters | 201 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.43, −0.26 |
Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SIR97 (Altomare et al., 1999), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H741···S1 | 0.88 (2) | 2.63 (2) | 3.5117 (14) | 178.4 (17) |
N4—H742···O2i | 0.86 (2) | 2.07 (2) | 2.8463 (16) | 150 (2) |
C9—H9···O1ii | 0.95 | 2.61 | 3.2807 (18) | 127.5 |
Symmetry codes: (i) −x+1, y−1/2, −z−1/2; (ii) −x, y−1/2, −z+1/2. |
Acknowledgements
The authors thank Mrs Isolda Williams for helpful discussions.
References
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Yan, G.-B., Zhang, C.-N. & Yang, M.-H. (2007). Acta Cryst. E63, o2663–o2664. Web of Science CSD CrossRef IUCr Journals Google Scholar
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Chelate ligands have found widespread use in coordination chemistry due to the enhanced thermodynamic stability of resultant coordination compounds in relation to coordination compounds exclusively applying comparable monodentate ligands (Gade, 1998). Combining different sets of donor atoms in one chelate ligand molecule, a probe for testing and accomodating metal centers of different Lewis acidities is at hand. To enable comparative studies with envisioned coordination compounds, we determined the crystal structure of the title compound. Other crystal structures of Schiff-bases derived from ortho-(thiomethyl)-benzaldehyde are reported in the literature (Yan et al., 2007; Baidina et al. 1987).
The molecule is a Schiff-base featuring an ortho-(thiomethyl)phenyl moiety and a 6-amino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione moiety. The double-bond is (E)-configured. A conformational analysis of the non-aromatic six-membered ring (Cremer & Pople, 1975) fails due to the low puckering amplitude. The molecule, excluding methyl hydrogen atoms is essentially planar, the least-squares planes defined by the respective atoms of both six-membered ring systems intersecting at an angle of only 12.24 (7)° (Fig. 1).
In the crystal structure, intra- as well as intermolecular hydrogen bonds can be observed, both supported by the amino group. While the intramolecular hydrogen bond is formed to the sulfur atom of the thiomethyl group, the intermolecular hydrogen bond uses one of the ketonic oxygen atoms as acceptor. Apart from these hydrogen bonds, C—H···O contacts whose range falls by more than 0.1 Å below the sum of van-der-Waals radii of the atoms participating are apparent. These stem from the H atom bonded to the C atom in para-position to the Schiff-base functionality on the aromatic ring and have the second ketonic O atom as acceptor. A description of the hydrogen bonding system in terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995) is possible with a DC11(6) descriptor on the unitary level, whereas the C—H···O contacts necessitate a C11(10) descriptor on the same level. In total, the molecules are linked in planes perpendicular to [1 0 1]. The shortest distance between the centroids of two heterocyclic rings was found to be 3.5268 (8) Å (Fig. 2). The packing of the title compound is shown in Fig. 3.