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Polymorph (Ia) (m.p. 474 K) of the title compound, C12H18N2O3, displays an N—H...O=C hydrogen-bonded layer structure which contains R66(28) rings connecting six mol­ecules, as well as R22(8) rings linking two mol­ecules. The 3-connected hydrogen-bonded net resulting from these inter­actions has the hcb topology. Form (Ib) (m.p. 471 K) displays N—H...O=C hydrogen-bonded looped chains in which neighbouring mol­ecules are linked to one another by two different R22(8) rings. Polymorph (Ia) is isostructural with the previously reported form II of 5-(2-bromo­all­yl)-5-iso­propyl­barbituric acid (noctal) and polymorph (Ib) is isostructural with the known crystal structures of four other barbiturates.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229615002880/cu3074sup1.cif
Contains datablocks Ia, Ib, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2053229615002880/cu3074Iasup2.hkl
Contains datablock Ia

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2053229615002880/cu3074Ibsup3.hkl
Contains datablock Ib

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S2053229615002880/cu3074Iasup4.cml
Supplementary material

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S2053229615002880/cu3074Ibsup5.cml
Supplementary material

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S2053229615002880/cu3074sup6.pdf
Supplementary material

CCDC references: 1048710; 1048709

Introduction top

The title compound [systematic name: 5-cyclo­hexyl-5-ethyl­pyrimidine-2,4,6(1H,3H,5H)-trione], (I) (see scheme), was investigated as part of a wider study of solid forms of barbiturates, 5-substituted derivatives of barbituric acid (Zencirci et al., 2009, 2010, 2014; Rossi et al., 2012). Barbiturates have been used as sedative, hypnotic and anti­convulsant agents, and the polymorphism and isomorphic relationships of selected members of this class have been investigated for several decades [see, for example, Brandstätter-Kuhnert & Aepkers (1961, 1962a,b, 1963)]. The core pyrimidine-2,4,6-trione unit contains a rigid arrangement of two N—H and three carbonyl groups, which can serve as donor and acceptor groups, respectively, for hydrogen bonds. This imposes limitations on the connectivity modes and geometries that are feasible for the formation of inter­molecular N—H···OC hydrogen-bonded structures, especially if no other functional groups for classical hydrogen bonding are available. The Cambridge Structural Database (CSD, Version 3.35; Groom & Allen, 2014) and the recent literature contain 51 unique crystal structures of barbiturates which have these characteristics, and the hydrogen-bonded structures (HBSs) formed in this set can be assigned to 12 distinct connectivity modes (Gelbrich et al., 2011). For a classification of the observed HBSs, one has to distinguish between the carbonyl group at position C2 on the one hand and the two topologically equivalent C4 and C6 carbonyl groups on the other (Fig. 1a). This set of barbiturate structures is dominated by four HBS types which are periodic in one dimension, e.g. two kinds of looped chain, a tape and a ladder structure (Gelbrich et al., 2011). The looped chains C-1 and C-2 (Figs. 1b and 1c) are the most important of these one-dimensional structures (see Table S1 of the Supporting information). By comparison, N—H···OC hydrogen-bonded layers and frameworks are rarely encountered in this group, with the exception of the subset of 5,5-dihalogen-substituted barbituric acid derivatives, which tend to form more complex HBSs (DesMarteau et al., 1994; Gelbrich et al., 2011).

Experimental top

Synthesis and crystallisation top

The synthesis of (I) was described by Kindler & Lührs (1965), who reported a melting point of 470 K. There is no previous report about the polymorphism of (I). The sample in our archive, synthesized by Kindler and co-workers more than 70 years ago, contained hexagonal plates of polymorph (Ia) and oblong prisms of form (Ib). It was characterised by hot-stage microscopy, FT–IR spectroscopy, powder X-ray crystallography and differential scanning calorimetry (for details, see the Supporting information). Sublimation experiments were carried out on a hot bench at 393, 423 and 463 K. A small amount of sample was placed on a glass slide and covered by a cylindrical-shaped glass bowl (diameter 6 mm, height 5 mm). After 1 d, the experiment at 393 K yielded isometric crystals of (Ia) in the hot section, close to the surface of the hot bench, and long prisms of form (Ib) in the cold section, on the surface of the inner bottom of the glass bowl. The other experiments resulted exclusively in form (Ib).

Hot-stage microscopy top

Heating of the original sample above 433 K on a hot stage resulted in intense sublimation, followed by the formation of secondary needle-shaped crystals. The oblong prisms of polymorph (Ib) melted at 469–473 K and the hexagonal plates of (Ia) at 473–476 K. The melt, still containing residual seeds of form (Ia), was left to cool, and at about 453 K the seeds grew rapidly into hexagonal or lath-shaped aggregates. Characteristic patterns of cracks appeared in these aggregates on further cooling below 396 K. A fraction of the remaining noncrystalline islands (undercooled melt) transformed into crystalline spherulitic aggregates at approximately the same temperature. These aggregates belong to a third polymorph, form (Ic), and show a distinct inter­nal feather pattern. The remaining islands of undercooled melt crystallized below 384 K as very fine needles which were arranged into a fuzzy pattern and represented a fourth polymorph, form (Id). On reheating, the transformations of the aggregates of forms (Ic) and (Id) into form (Ib) occur at about 393 and 413 K, respectively. With a very fast heating rate, melting of untransformed crystals was observed at approximately 443 K. It was not possible to produce larger qu­anti­ties of forms (Ic) and (Id) nor single crystals of these polymorphs suitable for X-ray crystallography.

Differential scanning calorimetry (DSC) and thermodynamic stability top

The DSC trace of the original sample containing a mixture of forms (Ia) and (Ib) shows two overlapping endothermic events (see Fig. S4 in the Supporting information). These indicate the melting process of form (Ib) with an onset temperature of about 469 K, followed by the melting of form (Ia), the main component of this sample, at about 474 K (onset temperature).

The melting endotherms of the two phase-pure forms (see Fig. S5 in the Supporting information) confirm that form (Ib) is the lower-melting polymorph. From a series of DSC experiments, the heats of fusion (ΔfusH) of forms (Ia) and (Ib) were determined to be 28.8±0.6 and 28.0±0.6 kJ mol-1 (95% c.i.), respectively, indicating that there is very little energy difference between the two forms. Form (Ia) has the higher melting point, as well as the higher heat of fusion. Application of the heat of fusion rule (Burger & Ramberger, 1979) would suggest a monotropic relationship in which form (Ia) is the more stable polymorph over the entire temperature range, but the statistical certainty associated with our data does not permit a reliable assessment in this regard. However, polymorph (Ib) is clearly more dense than (Ia) (by 1.9%). The density rule (Burger & Ramberger, 1979), which postulates that the denser phase should have a lower free energy at absolute zero, may not be applicable for polymorphs with strong hydrogen bonds and different Z'.

The available data do not permit a definitive assessment of the relative thermodynamic stability of forms (Ia) and (Ib). The co-existence of forms (Ia) and (Ib) in a 70-year-old sample investigated in this study indicates that both these polymorphs are kinetically highly stable.

Refinement top

Crystal data, data collection and structure refinement details are summarised in Table 1. All H atoms were identified in difference maps. Methyl H atoms were idealized and included as rigid groups allowed to rotate but not tip, with C—H = 0.98 Å. Other C-bound H atoms were positioned geometrically, with C—H = 0.99 Å for secondary (CH2) and tertiary (CH) C atoms. For all C-bound H atoms, Uiso(H) = 1.2Ueq(C) for CH and CH2 groups, or 1.5Ueq(C) for methyl groups. N-bound H atoms were refined with restrained distances N—H = 0.86 (2) Å, and their Uiso(H) parameters were refined freely.

Results and discussion top

Polymorph (Ia) crystallizes in the space group P21/c and contains two independent molecules (Fig. 2), denoted A and B, which adopt the same principle geometry. The cyclo­hexyl ring displays an almost ideal chair conformation, with an equatorial C5 substituent and with the ethyl group oriented trans relative to the C9—C5 bond (Fig. 3). The largest difference between molecules A and B occurs in the corresponding torsion angles C8—C7—C5—C9 (in molecule A) and C8'—C7'—C5'—C9' (in molecule B) of -173.8 (2) and -179.7 (2)°, respectively. The pyrimidine-2,4,6-trione units of molecules A and B are essentially planar, with the largest deviation shown by their C4 and C4' carbonyl groups, so that atoms O4 and O4' lie 0.109 (3) and 0.158 (3) Å, respectively, from the mean plane of the respective C4N2 ring.

Each molecule is bonded to two molecules of the same type via N1—H1···O4(x, -y + 3/2, z + 1/2) and N1'—H1'···O4'(x, -y + 1/2, z + 1/2) inter­actions which involve a glide mirror operation. Additionally, two A and B molecules are connected to one another by two anti­parallel inter­actions, (A)N3—H3···O2'(B) and (B)N3'—H3'···O2(A). Altogether, a hydrogen-bonded layer structure is formed (Fig. 4) which lies parallel to (100) and belongs to the L-4 type (Fig. 1d). It contains rings comprising six molecules, as well as dimeric units, which may be described in graph-set notation (Etter et al., 1990; Bernstein et al., 1995) as R66(28) and R22(8), respectively. There is only one previous example of this kind of N—H···O hydrogen-bonded layer among the 51 published crystal structures of analogous barbiturates. The underlying net of this HBS has the hcb topology (O'Keeffe et al., 2008), and the A and B molecules both serve as three-connected nodes and are topologically equivalent. The L-4 units of polymorph (Ia) are corrugated sheets with an inter­nal glide mirror symmetry, which are stacked along the a axis via inversion and 21 operations.

An XPac comparison (Gelbrich & Hursthouse, 2005) revealed that the crystal structure of form (Ia) is closely related to that of polymorph II of no­ctal [systematic name: 5-(2-bromo­allyl)-5-iso­propyl­barbituric acid; Gelbrich et al., 2011], the other known L-4 example, not just with regard to the topology of its HBS but indeed in its complete crystal packing arrangement (Fig. 5). Geometric differences between these two crystal structures result from shape and size differences in their substituent pairs at atom C5. This is reflected in the core dissimilarity index x11 (Gelbrich et al., 2012) of 10.9, calculated with parameters derived from matching non-H-atom positions of the pyrimidine-2,4,6-trione unit and the first C atom of each C5 substituent. Furthermore, the difference between the β angles of polymorph (Ia) and the no­ctal structure is 9.9° (see Table S2 of the Supporting information).

The space-group symmetry of the no­ctal structure is also P21/c, but its asymmetric unit contains just one molecule. Closer inspection shows that polymorph (Ia) has an approximate pseudosymmetry and is related to the no­ctal structure via a doubling of the a axis. In Fig. 5(a) (right), the break in the translation symmetry between neighbouring A and B molecules along [100] is visible as a slight offset between the two molecule types.

The molecular geometry of the C2/c polymorph, (Ib) (Fig. 6), is similar to that found in form (Ia) (Fig. 3). However, the ethyl group of (Ib) is oriented somewhat out-of-plane and the torsion angle C8—C7—C5—C9 = -160.77 (9)° is 13.0 and 18.9° smaller than the analogous values for molecules A and B of form (Ia). The C4 carbonyl group shows the largest deviation from the essentially planar pyrimidine ring, and the distance between atom O4 and the mean plane of the C4N2 ring is 0.162 (2) Å. Each molecule of polymorph (Ib) is bonded to two other molecules by two distinct anti­parallel two-point connections, viz. N1—H1···O2(-x + 1, y, -z - 1/2) and N3—H3···O4(-x + 1, y, -z + 1/2). These hydrogen bonds result in two independent R22(8) rings, the centres of which are inter­sected by crystallographic twofold axes. A looped hydrogen-bonded chain is formed, in which the two ring types alternate, and which runs parallel to [001]. This chain belongs to the C-1 type (Fig. 1b), the most common HBS for barbiturates (22 previous examples, see the Supporting information), which is distinct from the C-2 looped chain (eight examples). Neighbouring C-1 chains of polymorph (Ia) are arranged into centrosymmetric pairs in such a way that their mean planes, defined by C4N2 pyrimidine units, are parallel and the ethyl and cyclo­hexyl substituents are oriented towards the centre and the surface, respectively, of the resulting chain pair unit (Fig. 8a).

The formation of this kind of chain pair is a common feature in C-1 structures and an XPac analysis revealed that form (Ib) belongs to a larger subset characterized by extensive packing relationships. It is isostructural with the other four crystal structures listed in Table 4 and additionally with polymorph X of phenobarbital (Zencirci et al., 2009). Only two of the listed crystal structures have the maximum space-group symmetry (C2/c; Z' = 1), namely form (Ib) and polymorph I of ipral (systematic name: 5-ethyl-5-iso­propyl­barbituric acid). The unit-cell transformation between this structure and the two distinct P21/c (Z' = 2) settings of pseudosymmetric isostructures (CSD refcodes AMYTAL and BECLIE) was previously discussed by Zencirci et al. (2009). These lower-symmetry crystal structures are characterized by the absence of crystallographic twofold axes in their C-1 chains. XPac dissimilarity indices x12 were calculated for the comparison of form (Ib) with each of the other four structures listed in Table 4, using the matching non-H-atom positions of the pyrimidine-2,4,6-trione unit and the ethyl group, and additionally the C atom of the R5' substituent which is bonded to the pyrimidine ring. The x12 values obtained lie between 6.8 and 9.2, and are consistent with the accommodation of R5' substituents of different shapes and sizes in the same packing arrangement. Moreover, the isostructures listed in Table 4 show a two-dimensional packing similarity with each of the forms I and II of pentobarbital [systematic name: 5-ethyl-5-(1-methyl­butyl)­barbituric acid; Rossi et al., 2012], due to a common stacking mode of C-1 chain pairs.

In summary, the title compound exemplifies the propensity of barbiturates to crystallize in multiple solid forms, as well as their tendency to form isomorphic relationships. The specific energy contributions associated with competing hydrogen-bond motifs in the barbiturate class are currently being investigated in our laboratory and will be the topic of a future report.

Computing details top

Data collection: COLLECT (Nonius, 1998) for (Ia); CrysAlis PRO (Oxford Diffraction, 2010) for (Ib). Cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998) for (Ia); CrysAlis PRO (Oxford Diffraction, 2010) for (Ib). Data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998) for (Ia); CrysAlis PRO (Oxford Diffraction, 2010) for (Ib). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: XP (Bruker, 1998) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. (a) A simplified representation of a barbiturate molecule (additional circles denote carbonyl groups engaged in hydrogen bonding), used for the depiction of the hydrogen-bonded chain and layer structures, (b) C-1, polymorph (Ib), (c) C-2 and (d) L-4, polymorph (Ia).
[Figure 2] Fig. 2. The asymmetric unit of polymorph (Ia), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 3] Fig. 3. An overlay of the molecular geometries of polymorphs (Ia) and (Ib). The largest conformational differences occur in the torsion angle C9—C5—C8—C7, with a value of -173.9 (2)° for molecule A of (Ia), -179.7 (2)° for molecule B of (Ia) and -160.77 (9)° for (Ib). The r.m.s. distances are 0.061 Å for molecule A of (Ia) versus molecule B of (Ia), 0.090 Å for molecule A of (Ia) versus (Ib), and 0.1123 Å for molecule B of (Ia) versus (Ib).
[Figure 4] Fig. 4. The hydrogen-bonded L-4 structure of (Ia), viewed along [100]. H and O atoms engaged in hydrogen bonding are depicted as balls and all other H atoms have been omitted for clarity. Dashed lines indicate hydrogen bonds. The two graph sets are highlighted.
[Figure 5] Fig. 5. The three-dimensional packing similarity between (Ia) (top row) and polymorph II of noctal (bottom row). The crystal structures are shown in three matching views along corresponding lattice directions, and the core atoms used for XPac calculations (Gelbrich & Hursthouse, 2005) are drawn as balls. All other non-H atoms are drawn as capped sticks in the left-hand column of diagrams. In the centre and right-hand rows they have been omitted for clarity. Dashed lines indicate hydrogen bonds.
[Figure 6] Fig. 6. The asymmetric unit of form (Ib), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 7] Fig. 7. The hydrogen-bonded C-1 chain structure of polymorph (Ib). H and O atoms engaged in hydrogen bonding are depicted as balls and all other H atoms have been omitted for clarity. Dashed lines indicate hydrogen bonds. The graph set is highlighted. [Symmetry codes: (i) -x + 1, y, -z - 1/2; (ii) -x + 1, y, -z + 1/2. Please check]
[Figure 8] Fig. 8. The packing similarity between (a) form (Ib) and (b) polymorph I of ipral. Each crystal structure is viewed along its b axis. The core atoms used for the XPac calculations (Gelbrich & Hursthouse, 2005) are drawn as balls and all the other non-H atoms are drawn as capped sticks.
(Ia) 5-Cyclohexyl-5-ethylpyrimidine-2,4,6(1H,3H,5H)-trione top
Crystal data top
C12H18N2O3Dx = 1.281 Mg m3
Mr = 238.28Melting point: 473 K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 17.9322 (4) ÅCell parameters from 12888 reflections
b = 10.4961 (3) Åθ = 2.9–25.4°
c = 13.2006 (4) ŵ = 0.09 mm1
β = 95.896 (2)°T = 120 K
V = 2471.45 (12) Å3Plate, colourless
Z = 80.12 × 0.12 × 0.02 mm
F(000) = 1024
Data collection top
Bruker Nonius APEXII CCD camera on κ-goniostat
diffractometer
3416 reflections with I > 2σ(I)
Detector resolution: 65.3 pixels mm-1Rint = 0.054
ϕ and ω scansθmax = 25.4°, θmin = 3.0°
Absorption correction: multi-scan
(SADABS2007; Sheldrick, 2007)
h = 2121
Tmin = 0.989, Tmax = 0.998k = 1212
18686 measured reflectionsl = 1415
4513 independent reflections
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.061 w = 1/[σ2(Fo2) + 3.5813P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.125(Δ/σ)max < 0.001
S = 1.08Δρmax = 0.28 e Å3
4513 reflectionsΔρmin = 0.22 e Å3
326 parametersExtinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
4 restraintsExtinction coefficient: 0.0025 (4)
Crystal data top
C12H18N2O3V = 2471.45 (12) Å3
Mr = 238.28Z = 8
Monoclinic, P21/cMo Kα radiation
a = 17.9322 (4) ŵ = 0.09 mm1
b = 10.4961 (3) ÅT = 120 K
c = 13.2006 (4) Å0.12 × 0.12 × 0.02 mm
β = 95.896 (2)°
Data collection top
Bruker Nonius APEXII CCD camera on κ-goniostat
diffractometer
4513 independent reflections
Absorption correction: multi-scan
(SADABS2007; Sheldrick, 2007)
3416 reflections with I > 2σ(I)
Tmin = 0.989, Tmax = 0.998Rint = 0.054
18686 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0614 restraints
wR(F2) = 0.125H atoms treated by a mixture of independent and constrained refinement
S = 1.08Δρmax = 0.28 e Å3
4513 reflectionsΔρmin = 0.22 e Å3
326 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O20.26316 (9)0.61775 (17)0.62922 (12)0.0242 (4)
O40.33419 (10)0.66952 (17)0.31516 (13)0.0252 (4)
O60.41779 (10)0.94798 (17)0.58705 (13)0.0291 (4)
N10.34212 (12)0.7818 (2)0.60629 (16)0.0221 (5)
H10.3412 (16)0.800 (3)0.6700 (14)0.038 (9)*
N30.30390 (11)0.6441 (2)0.47334 (15)0.0207 (5)
H30.2791 (14)0.577 (2)0.453 (2)0.028 (8)*
C20.30070 (13)0.6774 (2)0.57355 (18)0.0194 (5)
C40.34150 (13)0.7068 (2)0.40309 (18)0.0191 (5)
C50.39087 (13)0.8194 (2)0.43796 (18)0.0188 (5)
C60.38503 (13)0.8564 (2)0.54859 (19)0.0207 (5)
C70.36728 (14)0.9357 (2)0.36998 (19)0.0244 (6)
H7A0.40321.00590.38750.029*
H7B0.37100.91230.29800.029*
C80.28861 (17)0.9841 (3)0.3797 (2)0.0405 (8)
H8A0.25270.91430.36590.061*
H8B0.27671.05290.33050.061*
H8C0.28571.01630.44880.061*
C90.47565 (13)0.7868 (2)0.43101 (19)0.0217 (6)
H90.50460.86540.45260.026*
C100.49536 (15)0.7552 (3)0.3234 (2)0.0304 (6)
H10A0.46890.67650.29890.037*
H10B0.47850.82540.27640.037*
C110.57990 (15)0.7363 (3)0.3235 (2)0.0371 (7)
H11A0.59130.71270.25420.044*
H11B0.60600.81740.34220.044*
C120.60870 (16)0.6328 (3)0.3983 (3)0.0408 (8)
H12A0.58650.54990.37570.049*
H12B0.66380.62590.39940.049*
C130.58859 (15)0.6626 (3)0.5045 (2)0.0375 (7)
H13A0.61530.74060.52990.045*
H13B0.60520.59160.55090.045*
C140.50427 (14)0.6821 (3)0.5056 (2)0.0291 (6)
H14A0.49330.70560.57520.035*
H14B0.47780.60140.48680.035*
O2'0.21369 (10)0.42669 (18)0.42118 (13)0.0278 (4)
O4'0.15416 (10)0.34154 (17)0.73713 (12)0.0253 (4)
O6'0.09393 (11)0.05615 (17)0.46154 (14)0.0300 (4)
N1'0.15211 (11)0.2426 (2)0.44330 (15)0.0203 (5)
H1'0.1556 (15)0.225 (3)0.3808 (14)0.027 (8)*
N3'0.17635 (11)0.3859 (2)0.57713 (15)0.0207 (5)
H3'0.1993 (14)0.453 (2)0.599 (2)0.029 (8)*
C2'0.18263 (13)0.3560 (2)0.47667 (18)0.0200 (5)
C4'0.14797 (13)0.3089 (2)0.64810 (18)0.0192 (5)
C5'0.11057 (13)0.1851 (2)0.61185 (18)0.0190 (5)
C6'0.11752 (13)0.1541 (2)0.50050 (19)0.0207 (5)
C7'0.14867 (14)0.0756 (3)0.67532 (19)0.0255 (6)
H7C0.13970.08750.74750.031*
H7D0.12500.00580.65180.031*
C8'0.23292 (17)0.0662 (4)0.6689 (2)0.0478 (9)
H8D0.24240.05350.59780.072*
H8E0.25320.00600.71000.072*
H8F0.25720.14510.69470.072*
C9'0.02403 (13)0.1901 (2)0.62223 (19)0.0214 (5)
H9A0.00310.10670.59600.026*
C10'0.01589 (14)0.2926 (3)0.5551 (2)0.0287 (6)
H10C0.00340.28210.48430.034*
H10D0.00180.37760.57940.034*
C11'0.10068 (15)0.2844 (3)0.5571 (2)0.0347 (7)
H11C0.12510.35450.51590.042*
H11D0.11910.20270.52670.042*
C12'0.12154 (16)0.2937 (3)0.6659 (2)0.0399 (8)
H12C0.10790.37920.69360.048*
H12D0.17640.28320.66570.048*
C13'0.08176 (15)0.1929 (3)0.7335 (2)0.0365 (7)
H13C0.09910.10740.70980.044*
H13D0.09450.20400.80420.044*
C14'0.00338 (14)0.2020 (3)0.7318 (2)0.0299 (6)
H14C0.02810.13330.77420.036*
H14D0.02140.28480.76080.036*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O20.0277 (9)0.0275 (10)0.0183 (9)0.0075 (8)0.0064 (7)0.0026 (8)
O40.0294 (10)0.0299 (10)0.0165 (10)0.0063 (8)0.0036 (7)0.0013 (8)
O60.0365 (11)0.0266 (10)0.0243 (10)0.0101 (8)0.0040 (8)0.0043 (8)
N10.0295 (12)0.0228 (12)0.0145 (11)0.0049 (9)0.0055 (9)0.0024 (9)
N30.0234 (11)0.0211 (11)0.0178 (11)0.0072 (9)0.0034 (9)0.0024 (9)
C20.0194 (12)0.0199 (13)0.0188 (13)0.0001 (10)0.0017 (10)0.0000 (11)
C40.0193 (12)0.0200 (13)0.0180 (13)0.0016 (10)0.0019 (10)0.0007 (10)
C50.0197 (12)0.0217 (13)0.0153 (12)0.0009 (10)0.0031 (9)0.0015 (10)
C60.0210 (12)0.0184 (13)0.0225 (14)0.0017 (10)0.0008 (10)0.0006 (11)
C70.0310 (14)0.0199 (13)0.0220 (14)0.0022 (11)0.0017 (11)0.0029 (11)
C80.0434 (18)0.0451 (19)0.0335 (17)0.0199 (15)0.0063 (14)0.0067 (14)
C90.0208 (13)0.0190 (13)0.0254 (14)0.0024 (10)0.0036 (10)0.0002 (11)
C100.0276 (14)0.0353 (16)0.0296 (15)0.0052 (12)0.0084 (12)0.0018 (13)
C110.0256 (15)0.0434 (18)0.0449 (18)0.0004 (13)0.0163 (13)0.0066 (15)
C120.0245 (15)0.0367 (17)0.062 (2)0.0059 (13)0.0057 (14)0.0028 (16)
C130.0259 (15)0.0345 (17)0.051 (2)0.0052 (12)0.0035 (13)0.0023 (15)
C140.0251 (14)0.0264 (15)0.0353 (16)0.0042 (11)0.0006 (11)0.0011 (12)
O2'0.0354 (10)0.0312 (11)0.0172 (9)0.0125 (8)0.0051 (8)0.0022 (8)
O4'0.0297 (10)0.0311 (10)0.0152 (9)0.0099 (8)0.0028 (7)0.0020 (8)
O6'0.0428 (11)0.0235 (10)0.0245 (10)0.0085 (9)0.0079 (8)0.0053 (8)
N1'0.0249 (11)0.0238 (12)0.0126 (11)0.0044 (9)0.0043 (9)0.0019 (9)
N3'0.0247 (11)0.0219 (11)0.0153 (11)0.0065 (9)0.0009 (8)0.0009 (9)
C2'0.0201 (12)0.0239 (14)0.0156 (12)0.0002 (10)0.0003 (10)0.0006 (11)
C4'0.0164 (12)0.0236 (13)0.0178 (13)0.0005 (10)0.0024 (9)0.0024 (11)
C5'0.0206 (12)0.0206 (13)0.0159 (12)0.0003 (10)0.0028 (10)0.0013 (10)
C6'0.0207 (12)0.0215 (13)0.0203 (13)0.0015 (10)0.0033 (10)0.0006 (11)
C7'0.0320 (14)0.0248 (14)0.0201 (14)0.0056 (11)0.0044 (11)0.0036 (11)
C8'0.0411 (18)0.069 (2)0.0347 (18)0.0292 (17)0.0124 (14)0.0163 (17)
C9'0.0168 (12)0.0237 (13)0.0237 (13)0.0025 (10)0.0021 (10)0.0032 (11)
C10'0.0269 (14)0.0314 (15)0.0272 (15)0.0042 (11)0.0003 (11)0.0004 (12)
C11'0.0243 (14)0.0417 (18)0.0370 (17)0.0060 (12)0.0027 (12)0.0076 (14)
C12'0.0253 (15)0.0480 (19)0.0468 (19)0.0039 (13)0.0060 (13)0.0162 (15)
C13'0.0253 (14)0.056 (2)0.0295 (16)0.0035 (14)0.0073 (12)0.0075 (14)
C14'0.0229 (13)0.0416 (17)0.0258 (15)0.0030 (12)0.0054 (11)0.0037 (13)
Geometric parameters (Å, º) top
O2—C21.219 (3)O2'—C2'1.217 (3)
O4—C41.219 (3)O4'—C4'1.218 (3)
O6—C61.210 (3)O6'—C6'1.207 (3)
N1—C21.369 (3)N1'—C2'1.364 (3)
N1—C61.381 (3)N1'—C6'1.383 (3)
N1—H10.865 (17)N1'—H1'0.854 (17)
N3—C41.370 (3)N3'—C4'1.374 (3)
N3—C21.375 (3)N3'—C2'1.379 (3)
N3—H30.862 (17)N3'—H3'0.853 (17)
C4—C51.520 (3)C4'—C5'1.517 (3)
C5—C61.525 (3)C5'—C6'1.523 (3)
C5—C71.548 (3)C5'—C7'1.540 (3)
C5—C91.570 (3)C5'—C9'1.573 (3)
C7—C81.517 (4)C7'—C8'1.525 (4)
C7—H7A0.9900C7'—H7C0.9900
C7—H7B0.9900C7'—H7D0.9900
C8—H8A0.9800C8'—H8D0.9800
C8—H8B0.9800C8'—H8E0.9800
C8—H8C0.9800C8'—H8F0.9800
C9—C141.529 (4)C9'—C10'1.524 (4)
C9—C101.535 (3)C9'—C14'1.534 (3)
C9—H91.0000C9'—H9A1.0000
C10—C111.529 (4)C10'—C11'1.526 (4)
C10—H10A0.9900C10'—H10C0.9900
C10—H10B0.9900C10'—H10D0.9900
C11—C121.523 (4)C11'—C12'1.523 (4)
C11—H11A0.9900C11'—H11C0.9900
C11—H11B0.9900C11'—H11D0.9900
C12—C131.516 (4)C12'—C13'1.515 (4)
C12—H12A0.9900C12'—H12C0.9900
C12—H12B0.9900C12'—H12D0.9900
C13—C141.527 (4)C13'—C14'1.532 (4)
C13—H13A0.9900C13'—H13C0.9900
C13—H13B0.9900C13'—H13D0.9900
C14—H14A0.9900C14'—H14C0.9900
C14—H14B0.9900C14'—H14D0.9900
C2—N1—C6126.5 (2)C2'—N1'—C6'126.7 (2)
C2—N1—H1115 (2)C2'—N1'—H1'115.7 (19)
C6—N1—H1118 (2)C6'—N1'—H1'117.7 (19)
C4—N3—C2126.9 (2)C4'—N3'—C2'126.5 (2)
C4—N3—H3116.9 (19)C4'—N3'—H3'117.5 (19)
C2—N3—H3116.2 (19)C2'—N3'—H3'115.1 (19)
O2—C2—N1122.4 (2)O2'—C2'—N1'122.1 (2)
O2—C2—N3121.9 (2)O2'—C2'—N3'121.8 (2)
N1—C2—N3115.6 (2)N1'—C2'—N3'116.1 (2)
O4—C4—N3118.6 (2)O4'—C4'—N3'119.3 (2)
O4—C4—C5122.7 (2)O4'—C4'—C5'122.6 (2)
N3—C4—C5118.7 (2)N3'—C4'—C5'118.1 (2)
C4—C5—C6113.13 (19)C4'—C5'—C6'114.2 (2)
C4—C5—C7108.8 (2)C4'—C5'—C7'108.1 (2)
C6—C5—C7108.2 (2)C6'—C5'—C7'106.9 (2)
C4—C5—C9110.50 (19)C4'—C5'—C9'110.64 (19)
C6—C5—C9105.88 (19)C6'—C5'—C9'105.70 (19)
C7—C5—C9110.28 (19)C7'—C5'—C9'111.3 (2)
O6—C6—N1119.5 (2)O6'—C6'—N1'119.8 (2)
O6—C6—C5121.7 (2)O6'—C6'—C5'122.2 (2)
N1—C6—C5118.7 (2)N1'—C6'—C5'118.0 (2)
C8—C7—C5114.6 (2)C8'—C7'—C5'113.9 (2)
C8—C7—H7A108.6C8'—C7'—H7C108.8
C5—C7—H7A108.6C5'—C7'—H7C108.8
C8—C7—H7B108.6C8'—C7'—H7D108.8
C5—C7—H7B108.6C5'—C7'—H7D108.8
H7A—C7—H7B107.6H7C—C7'—H7D107.7
C7—C8—H8A109.5C7'—C8'—H8D109.5
C7—C8—H8B109.5C7'—C8'—H8E109.5
H8A—C8—H8B109.5H8D—C8'—H8E109.5
C7—C8—H8C109.5C7'—C8'—H8F109.5
H8A—C8—H8C109.5H8D—C8'—H8F109.5
H8B—C8—H8C109.5H8E—C8'—H8F109.5
C14—C9—C10110.3 (2)C10'—C9'—C14'110.2 (2)
C14—C9—C5112.5 (2)C10'—C9'—C5'112.4 (2)
C10—C9—C5114.7 (2)C14'—C9'—C5'114.9 (2)
C14—C9—H9106.3C10'—C9'—H9A106.2
C10—C9—H9106.3C14'—C9'—H9A106.2
C5—C9—H9106.3C5'—C9'—H9A106.2
C11—C10—C9110.5 (2)C9'—C10'—C11'111.1 (2)
C11—C10—H10A109.6C9'—C10'—H10C109.4
C9—C10—H10A109.6C11'—C10'—H10C109.4
C11—C10—H10B109.6C9'—C10'—H10D109.4
C9—C10—H10B109.6C11'—C10'—H10D109.4
H10A—C10—H10B108.1H10C—C10'—H10D108.0
C12—C11—C10111.3 (2)C12'—C11'—C10'110.7 (2)
C12—C11—H11A109.4C12'—C11'—H11C109.5
C10—C11—H11A109.4C10'—C11'—H11C109.5
C12—C11—H11B109.4C12'—C11'—H11D109.5
C10—C11—H11B109.4C10'—C11'—H11D109.5
H11A—C11—H11B108.0H11C—C11'—H11D108.1
C13—C12—C11110.8 (2)C13'—C12'—C11'111.4 (2)
C13—C12—H12A109.5C13'—C12'—H12C109.4
C11—C12—H12A109.5C11'—C12'—H12C109.4
C13—C12—H12B109.5C13'—C12'—H12D109.4
C11—C12—H12B109.5C11'—C12'—H12D109.4
H12A—C12—H12B108.1H12C—C12'—H12D108.0
C12—C13—C14111.5 (2)C12'—C13'—C14'110.9 (2)
C12—C13—H13A109.3C12'—C13'—H13C109.5
C14—C13—H13A109.3C14'—C13'—H13C109.5
C12—C13—H13B109.3C12'—C13'—H13D109.5
C14—C13—H13B109.3C14'—C13'—H13D109.5
H13A—C13—H13B108.0H13C—C13'—H13D108.0
C13—C14—C9110.9 (2)C13'—C14'—C9'110.3 (2)
C13—C14—H14A109.5C13'—C14'—H14C109.6
C9—C14—H14A109.5C9'—C14'—H14C109.6
C13—C14—H14B109.5C13'—C14'—H14D109.6
C9—C14—H14B109.5C9'—C14'—H14D109.6
H14A—C14—H14B108.0H14C—C14'—H14D108.1
C6—N1—C2—O2178.7 (2)C6'—N1'—C2'—N3'1.8 (4)
C6—N1—C2—N31.1 (4)C4'—N3'—C2'—O2'174.4 (2)
C4—N3—C2—O2177.1 (2)C4'—N3'—C2'—N1'5.5 (4)
C4—N3—C2—N12.7 (4)C2'—N3'—C4'—O4'171.1 (2)
C2—N3—C4—O4174.8 (2)C2'—N3'—C4'—C5'8.3 (4)
C2—N3—C4—C55.5 (4)O4'—C4'—C5'—C6'172.5 (2)
O4—C4—C5—C6174.2 (2)N3'—C4'—C5'—C6'6.9 (3)
N3—C4—C5—C66.1 (3)O4'—C4'—C5'—C7'53.8 (3)
O4—C4—C5—C753.9 (3)N3'—C4'—C5'—C7'125.7 (2)
N3—C4—C5—C7126.4 (2)O4'—C4'—C5'—C9'68.4 (3)
O4—C4—C5—C967.3 (3)N3'—C4'—C5'—C9'112.2 (2)
N3—C4—C5—C9112.4 (2)C2'—N1'—C6'—O6'178.8 (2)
C2—N1—C6—O6178.5 (2)C2'—N1'—C6'—C5'1.3 (4)
C2—N1—C6—C52.5 (4)C4'—C5'—C6'—O6'176.3 (2)
C4—C5—C6—O6176.3 (2)C7'—C5'—C6'—O6'56.9 (3)
C7—C5—C6—O655.7 (3)C9'—C5'—C6'—O6'61.8 (3)
C9—C5—C6—O662.5 (3)C4'—C5'—C6'—N1'3.8 (3)
C4—C5—C6—N14.8 (3)C7'—C5'—C6'—N1'123.2 (2)
C7—C5—C6—N1125.4 (2)C9'—C5'—C6'—N1'118.1 (2)
C9—C5—C6—N1116.4 (2)C4'—C5'—C7'—C8'58.0 (3)
C4—C5—C7—C864.9 (3)C6'—C5'—C7'—C8'65.4 (3)
C6—C5—C7—C858.4 (3)C9'—C5'—C7'—C8'179.7 (2)
C9—C5—C7—C8173.8 (2)C4'—C5'—C9'—C10'63.3 (3)
C4—C5—C9—C1466.0 (3)C6'—C5'—C9'—C10'60.9 (3)
C6—C5—C9—C1456.8 (3)C7'—C5'—C9'—C10'176.5 (2)
C7—C5—C9—C14173.7 (2)C4'—C5'—C9'—C14'63.9 (3)
C4—C5—C9—C1061.0 (3)C6'—C5'—C9'—C14'172.0 (2)
C6—C5—C9—C10176.1 (2)C7'—C5'—C9'—C14'56.3 (3)
C7—C5—C9—C1059.3 (3)C14'—C9'—C10'—C11'57.3 (3)
C14—C9—C10—C1156.8 (3)C5'—C9'—C10'—C11'173.2 (2)
C5—C9—C10—C11175.1 (2)C9'—C10'—C11'—C12'56.3 (3)
C9—C10—C11—C1256.8 (3)C10'—C11'—C12'—C13'55.8 (3)
C10—C11—C12—C1356.1 (3)C11'—C12'—C13'—C14'56.4 (3)
C11—C12—C13—C1455.7 (3)C12'—C13'—C14'—C9'57.0 (3)
C12—C13—C14—C956.3 (3)C10'—C9'—C14'—C13'57.3 (3)
C10—C9—C14—C1356.5 (3)C5'—C9'—C14'—C13'174.5 (2)
C5—C9—C14—C13174.2 (2)C9—C5—C7—C8173.8 (2)
C6'—N1'—C2'—O2'178.2 (2)C9'—C5'—C7'—C8'179.7 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O4i0.87 (2)1.96 (2)2.822 (3)175 (3)
N3—H3···O20.86 (2)1.98 (2)2.840 (3)172 (3)
N1—H1···O4ii0.85 (2)2.02 (2)2.865 (3)171 (3)
N3—H3···O20.85 (2)2.09 (2)2.932 (3)171 (3)
Symmetry codes: (i) x, y+3/2, z+1/2; (ii) x, y+1/2, z1/2.
(Ib) 5-Cyclohexyl-5-ethylpyrimidine-2,4,6(1H,3H,5H)-trione top
Crystal data top
C12H18N2O3Dx = 1.305 Mg m3
Mr = 238.28Melting point: 462 K
Monoclinic, C2/cCu Kα radiation, λ = 1.5418 Å
a = 12.5071 (7) ÅCell parameters from 4171 reflections
b = 21.0741 (9) Åθ = 4.0–67.3°
c = 10.3310 (5) ŵ = 0.77 mm1
β = 116.989 (5)°T = 173 K
V = 2426.4 (2) Å3Prism, colourless
Z = 80.60 × 0.08 × 0.08 mm
F(000) = 1024
Data collection top
Oxford Xcalibur
diffractometer with Gemini Ultra Ruby CCD detector [OK?]
2188 independent reflections
Radiation source: Enhance Ultra (Cu) X-ray Source1897 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.024
Detector resolution: 10.3575 pixels mm-1θmax = 67.4°, θmin = 4.2°
ω scansh = 1414
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2010)
k = 2524
Tmin = 0.932, Tmax = 1.000l = 1211
6607 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.035H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.099 w = 1/[σ2(Fo2) + (0.0583P)2 + 0.7034P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max < 0.001
2188 reflectionsΔρmax = 0.29 e Å3
164 parametersΔρmin = 0.23 e Å3
2 restraintsExtinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.00111 (15)
Crystal data top
C12H18N2O3V = 2426.4 (2) Å3
Mr = 238.28Z = 8
Monoclinic, C2/cCu Kα radiation
a = 12.5071 (7) ŵ = 0.77 mm1
b = 21.0741 (9) ÅT = 173 K
c = 10.3310 (5) Å0.60 × 0.08 × 0.08 mm
β = 116.989 (5)°
Data collection top
Oxford Xcalibur
diffractometer with Gemini Ultra Ruby CCD detector [OK?]
2188 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2010)
1897 reflections with I > 2σ(I)
Tmin = 0.932, Tmax = 1.000Rint = 0.024
6607 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0352 restraints
wR(F2) = 0.099H atoms treated by a mixture of independent and constrained refinement
S = 1.08Δρmax = 0.29 e Å3
2188 reflectionsΔρmin = 0.23 e Å3
164 parameters
Special details top

Experimental. CrysAlisPro (Oxford Diffraction, 2010) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O20.44099 (7)0.07368 (4)0.13883 (9)0.0313 (2)
O40.65981 (7)0.06726 (4)0.34585 (8)0.0293 (2)
O60.84171 (7)0.08917 (5)0.03118 (9)0.0344 (3)
N10.64283 (9)0.07951 (5)0.05071 (11)0.0246 (2)
H10.6315 (14)0.0791 (7)0.1393 (19)0.036 (4)*
N30.55393 (8)0.07662 (5)0.10429 (10)0.0222 (2)
H30.4920 (14)0.0726 (6)0.1154 (15)0.028 (4)*
C20.54014 (10)0.07646 (5)0.03538 (12)0.0218 (3)
C40.66090 (10)0.07439 (5)0.22940 (12)0.0215 (3)
C50.77686 (10)0.08310 (5)0.21676 (12)0.0229 (3)
C60.75865 (10)0.08392 (5)0.06019 (12)0.0241 (3)
C70.86557 (10)0.02881 (6)0.29951 (12)0.0259 (3)
H7A0.94770.04260.32120.031*
H7B0.86390.02210.39340.031*
C80.84039 (11)0.03426 (6)0.21941 (14)0.0323 (3)
H8A0.75820.04770.19370.049*
H8B0.89700.06630.28210.049*
H8C0.84980.02940.13080.049*
C90.83334 (11)0.14932 (6)0.28090 (13)0.0294 (3)
H90.90470.15380.26230.035*
C100.88127 (14)0.15489 (7)0.44579 (15)0.0421 (4)
H10A0.81390.15220.47100.051*
H10B0.93730.11950.49460.051*
C110.9462 (2)0.21825 (9)0.4979 (2)0.0684 (6)
H11A0.97340.22260.60360.082*
H11B1.01800.21900.48100.082*
C120.8653 (2)0.27382 (9)0.4192 (2)0.0776 (7)
H12A0.91150.31380.45200.093*
H12B0.79810.27580.44470.093*
C130.81515 (19)0.26823 (8)0.2552 (2)0.0594 (5)
H3A0.88130.27160.22800.071*
H3B0.75830.30340.20770.071*
C140.75063 (14)0.20474 (6)0.20239 (18)0.0428 (4)
H14A0.67910.20350.21990.051*
H14B0.72310.20070.09650.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O20.0191 (4)0.0515 (6)0.0207 (4)0.0027 (4)0.0069 (3)0.0022 (3)
O40.0211 (4)0.0490 (5)0.0200 (4)0.0010 (4)0.0113 (3)0.0032 (3)
O60.0213 (4)0.0601 (6)0.0262 (4)0.0023 (4)0.0146 (4)0.0049 (4)
N10.0204 (5)0.0377 (6)0.0170 (5)0.0013 (4)0.0096 (4)0.0010 (4)
N30.0149 (5)0.0328 (5)0.0209 (5)0.0003 (4)0.0099 (4)0.0009 (4)
C20.0199 (6)0.0242 (6)0.0214 (6)0.0003 (4)0.0095 (5)0.0005 (4)
C40.0191 (6)0.0259 (6)0.0205 (6)0.0010 (4)0.0098 (4)0.0005 (4)
C50.0161 (5)0.0338 (6)0.0192 (6)0.0003 (4)0.0083 (4)0.0011 (4)
C60.0196 (6)0.0318 (6)0.0221 (6)0.0024 (4)0.0106 (5)0.0023 (4)
C70.0166 (5)0.0396 (7)0.0211 (6)0.0031 (5)0.0083 (4)0.0035 (5)
C80.0244 (6)0.0372 (7)0.0355 (7)0.0022 (5)0.0137 (5)0.0025 (5)
C90.0247 (6)0.0368 (7)0.0305 (6)0.0066 (5)0.0158 (5)0.0036 (5)
C100.0479 (8)0.0474 (8)0.0338 (7)0.0158 (7)0.0209 (6)0.0125 (6)
C110.0898 (14)0.0702 (12)0.0513 (10)0.0469 (11)0.0374 (10)0.0285 (9)
C120.1261 (19)0.0433 (10)0.0931 (15)0.0387 (11)0.0757 (15)0.0294 (10)
C130.0767 (12)0.0370 (9)0.0809 (12)0.0130 (8)0.0499 (10)0.0039 (8)
C140.0423 (8)0.0332 (7)0.0584 (9)0.0018 (6)0.0276 (7)0.0015 (6)
Geometric parameters (Å, º) top
O2—C21.2168 (14)C8—H8C0.9800
O4—C41.2186 (14)C9—C141.5267 (19)
O6—C61.2098 (14)C9—C101.5323 (17)
N1—C21.3651 (15)C9—H91.0000
N1—C61.3832 (15)C10—C111.528 (2)
N1—H10.860 (18)C10—H10A0.9900
N3—C21.3733 (15)C10—H10B0.9900
N3—C41.3759 (15)C11—C121.520 (3)
N3—H30.838 (16)C11—H11A0.9900
C4—C51.5252 (15)C11—H11B0.9900
C5—C61.5278 (15)C12—C131.521 (3)
C5—C71.5523 (15)C12—H12A0.9900
C5—C91.5687 (16)C12—H12B0.9900
C7—C81.5213 (18)C13—C141.529 (2)
C7—H7A0.9900C13—H3A0.9900
C7—H7B0.9900C13—H3B0.9900
C8—H8A0.9800C14—H14A0.9900
C8—H8B0.9800C14—H14B0.9900
C2—N1—C6126.43 (10)C10—C9—C5114.32 (10)
C2—N1—H1114.4 (11)C14—C9—H9105.9
C6—N1—H1119.1 (10)C10—C9—H9105.9
C2—N3—C4126.29 (10)C5—C9—H9105.9
C2—N3—H3117.4 (10)C11—C10—C9109.62 (12)
C4—N3—H3115.7 (10)C11—C10—H10A109.7
O2—C2—N1122.54 (10)C9—C10—H10A109.7
O2—C2—N3121.00 (10)C11—C10—H10B109.7
N1—C2—N3116.46 (10)C9—C10—H10B109.7
O4—C4—N3119.33 (10)H10A—C10—H10B108.2
O4—C4—C5122.44 (10)C12—C11—C10111.51 (16)
N3—C4—C5118.20 (9)C12—C11—H11A109.3
C4—C5—C6113.67 (9)C10—C11—H11A109.3
C4—C5—C7109.51 (9)C12—C11—H11B109.3
C6—C5—C7108.50 (9)C10—C11—H11B109.3
C4—C5—C9109.53 (9)H11A—C11—H11B108.0
C6—C5—C9105.03 (9)C11—C12—C13111.98 (15)
C7—C5—C9110.53 (9)C11—C12—H12A109.2
O6—C6—N1119.68 (10)C13—C12—H12A109.2
O6—C6—C5122.08 (10)C11—C12—H12B109.2
N1—C6—C5118.23 (10)C13—C12—H12B109.2
C8—C7—C5115.12 (9)H12A—C12—H12B107.9
C8—C7—H7A108.5C12—C13—C14110.45 (14)
C5—C7—H7A108.5C12—C13—H3A109.6
C8—C7—H7B108.5C14—C13—H3A109.6
C5—C7—H7B108.5C12—C13—H3B109.6
H7A—C7—H7B107.5C14—C13—H3B109.6
C7—C8—H8A109.5H3A—C13—H3B108.1
C7—C8—H8B109.5C9—C14—C13111.05 (13)
H8A—C8—H8B109.5C9—C14—H14A109.4
C7—C8—H8C109.5C13—C14—H14A109.4
H8A—C8—H8C109.5C9—C14—H14B109.4
H8B—C8—H8C109.5C13—C14—H14B109.4
C14—C9—C10111.16 (11)H14A—C14—H14B108.0
C14—C9—C5112.93 (10)
C8—C7—C5—C9160.77 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O2i0.86 (2)2.05 (2)2.8896 (13)165 (2)
N3—H3···O4ii0.84 (2)2.11 (2)2.9497 (13)176 (1)
Symmetry codes: (i) x+1, y, z1/2; (ii) x+1, y, z+1/2.

Experimental details

(Ia)(Ib)
Crystal data
Chemical formulaC12H18N2O3C12H18N2O3
Mr238.28238.28
Crystal system, space groupMonoclinic, P21/cMonoclinic, C2/c
Temperature (K)120173
a, b, c (Å)17.9322 (4), 10.4961 (3), 13.2006 (4)12.5071 (7), 21.0741 (9), 10.3310 (5)
β (°) 95.896 (2) 116.989 (5)
V3)2471.45 (12)2426.4 (2)
Z88
Radiation typeMo KαCu Kα
µ (mm1)0.090.77
Crystal size (mm)0.12 × 0.12 × 0.020.60 × 0.08 × 0.08
Data collection
DiffractometerBruker Nonius APEXII CCD camera on κ-goniostat
diffractometer
Oxford Xcalibur
diffractometer with Gemini Ultra Ruby CCD detector [OK?]
Absorption correctionMulti-scan
(SADABS2007; Sheldrick, 2007)
Multi-scan
(CrysAlis PRO; Oxford Diffraction, 2010)
Tmin, Tmax0.989, 0.9980.932, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
18686, 4513, 3416 6607, 2188, 1897
Rint0.0540.024
(sin θ/λ)max1)0.6030.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.061, 0.125, 1.08 0.035, 0.099, 1.08
No. of reflections45132188
No. of parameters326164
No. of restraints42
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.28, 0.220.29, 0.23

Computer programs: , CrysAlis PRO (Oxford Diffraction, 2010), DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2015), XP (Bruker, 1998) and Mercury (Macrae et al., 2008), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) for (Ia) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O4i0.865 (17)1.959 (18)2.822 (3)175 (3)
N3—H3···O2'0.862 (17)1.984 (18)2.840 (3)172 (3)
N1'—H1'···O4'ii0.854 (17)2.019 (18)2.865 (3)171 (3)
N3'—H3'···O20.853 (17)2.087 (18)2.932 (3)171 (3)
Symmetry codes: (i) x, y+3/2, z+1/2; (ii) x, y+1/2, z1/2.
Hydrogen-bond geometry (Å, º) for (Ib) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O2i0.860 (18)2.050 (18)2.8896 (13)165.0 (15)
N3—H3···O4ii0.838 (16)2.113 (16)2.9497 (13)176.1 (14)
Symmetry codes: (i) x+1, y, z1/2; (ii) x+1, y, z+1/2.
Details for a set of isostructural crystal structures and XPac dissimilarity paramers x12 for pairwise comparison with polymorph (Ib). R5 and R5' are the 5-position substituents of the pyrimidinetrione unit. top
R5R5'Space groupZCSD refcodeReferencex12
EthylCyclohexylC2/c1Polymorph (Ib)
EthylIsopropylC2/c1FUFTAC(Zencirci et al., 2009)6.8
EthylPentan-2-yl/phenylC2/c1LATMEA(Rossi et al., 2012)7.0
Ethyl3-MethylbutylP21/ca2AMYTAL11(Craven & Vizzini, 1969)7.1
Ethyl3-Methylbut-2-enylP21/c2BECLIE(Jones & Andrews, 1981)9.2
Note: (a) the space group is P21/n with reference to the setting used for the C2/c structures listed in the rows above (for details, see Zencirci et al., 2009).
 

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