Synthesis, crystal structure and Hirshfeld surface analysis of 2-[(4-hydroxyphenyl)amino]-5,5-diphenyl-1H-imidazol-4(5H)-one

The five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, five-membered ring vary between 50.78 (4) and 86.78 (10)°. In the crystal, O—H⋯N hydrogen bonds and weak π-stacking interactions form inversion dimers, which are linked into chains extending along the c-axis direction by two sets of N—H⋯O hydrogen bonds. The chains are connected into layers parallel to the bc plane by two sets of C—H⋯π(ring) interactions.


Chemical context
Hydantoins or imidazolidine-2,4-diones are heterocyclic compounds characterized by the presence of an imidazole ring and keto groups in positions 2 and 4. Hydantoin-containing compounds exhibit a broad spectrum of pharmacological and biological activities such as an anticancer (Cao et al., 2022), antibacterial (Ghasempour et al., 2021;El Moutaouakil Ala Allah et al., 2024), antidiabetic (Sergent et al., 2008), antiinflammatory (Lin et al., 2021), antimicrobial (Shaala & Youssef, 2021), anticonvulsant (Byrtus et al., 2011) and anti-HIV (Romine et al., 2011) activities.Thiohydantoins, sulfur analogues of hydantoins, undergo replacement of one or both carbonyl groups with thiocarbonyl groups (Johnson & Scott, 1913;Wyzlic et al., 1996;Cromwell & Stark, 1969).This substitution enables versatile structural modifications, facilitating the customization of thiohydantoins to preferentially adopt specific structural types.Such modifications, achieved by introducing steric bulk, altering hydrophilic or hydrophobic interactions, or promoting �-� stacking, afford control over the molecule's ability to form hydrogen-bonded arrays in the solid state.Hence, the capacity to manipulate the formation of hydrogen-bonded arrays in the solid state is of vital importance in the pharmaceutical field (Lu & Rohani, 2009).

Figure 1
The molecular structure of the title molecule with labelling scheme and 50% probability ellipsoids.
with Cu II and so are not directly comparable to the title molecule because of the constraints imposed by coordination to the metal.In REFREB, the five-membered ring adopts an envelope conformation with C4 at the tip of the flap and 0.044 (6) A ˚from the mean plane (r.m.s.deviation of the fitted atoms = 0.003 A ˚) with the mean planes of the attached phenyl rings inclined to the above plane by 63.3 (2) and 82.9 (2) � , respectively, which are similar to the corresponding angles in the title molecule.Also, the torsion angle corresponding to the C16-N3-C3-N1 angle in the title molecule is for REFREB À 8.0 (5) � , which is again comparable to that cited above although the remainder of the ester chain is pointed away from the plane of the five-membered ring.

Hirshfeld surface analysis
A Hirshfeld surface analysis was performed using Crystal-Explorer21 (Turner et al., 2017) to evaluate the relative contributions of the intermolecular interactions in the crystal.Fragment used in the CSD search.

Figure 5
Front and back views of the Hirshfeld surface for the title molecule mapped over d norm .

Figure 6
The Additional details of the plots produced and their interpretation have been published (Tan et al., 2019).Fig. 5 presents two views of the surface mapped over d norm together with four neighbouring molecules showing the intermolecular N-H� � �O and O-H� � �N hydrogen bonds as well as one of the C-H� � ��(ring) interactions.From the 2D fingerprint plots, the major intermolecular interactions, comprising 48.7% of the total, are H� � �H contacts (Fig. 6b), appearing as a broad central peak and which are presumed to be van der Waals contacts.At 28.9% of the total are the C� � �H/H� � �C contacts (Fig. 6c), shown as two broad peaks at d e + d i = 3.14 A ˚, which are primarily the two sets of C-H� � ��(ring) interactions (Table 1) with the width of the peaks due to the range of H� � �C distances from the hydrogen atom in question to the several carbon atoms of the ring.The O� � �H/H� � �O (Fig. 6d) and N� � �H/H� � �N (Fig. 6e) contacts appear as sharp spikes at d e + d i = 2.16 and 2.20 A ˚, respectively, contributing 13.3% and 6.9%, respectively.

Synthesis and crystallization
The synthesis of the title compound is shown in Fig. 7.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. Analysis of 185 reflections having I/�(I) > 12 and chosen from the full data set with CELL_NOW (Sheldrick, 2008a) showed the crystal to belong to the monoclinic system and to be twinned by a 180 � rotation about the c*-axis.The raw data were processed using the multicomponent version of SAINT under control of the twocomponent orientation file generated by CELL_NOW.The final refinement used the full twinned dataset.H atoms attached to carbon were placed in calculated positions and were included as riding contributions with isotropic displacement parameters 1.2-1.5 times those of the attached atoms.Those attached to nitrogen and to oxygen were placed in locations derived from a difference map and refined with DFIX 0.91 0.01 and DFIX 0.84 0.01 instructions, respectively.One reflection affected by the beamstop was omitted from the final refinement.

Special details
Experimental.The diffraction data were collected in three sets of 363 frames 0.5° width in ω) at φ = 0, 120 and 240°.A scan time of 60 sec/frame was used.Analysis of 185 reflections having I/σ(I) > 12 and chosen from the full data set with CELL_NOW (Sheldrick, 2008) showed the crystal to belong to the monoclinic system and to be twinned by a 180° rotation about the c* axis.The raw data were processed using the multi-component version of SAINT under control of the two-component orientation file generated by CELL_NOW.Geometry.All esds (except the esd in the dihedral angle between two l.s.planes) are estimated using the full covariance matrix.The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry.An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s.planes.Refinement.Refinement of F 2 against ALL reflections.The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 .The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement.R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.H-atoms attached to carbon were placed in calculated positions (C-H = 0.95 -0.98 Å) and were included as riding contributions with isotropic displacement parameters 1.2 -1.5 times those of the attached atoms.Those attached to nitrogen and to oxygen were placed in locations derived from a difference map and refined with DFIX 0.91 0.01 and DFIX 0.84 0.01 instructions, respectively.Refined as a 2-component twin.One reflection affected by the beamstop was omitted from the final refinement.

Figure 2 A
Figure 2 A portion of one chain of molecules viewed along the b-axis direction.O-H� � �N and N-H� � �O hydrogen bonds are depicted, respectively, by pink and violet dashed lines and non-interacting hydrogen atoms are omitted for clarity.

Figure 3
Figure 3Packing viewed along the c-axis direction with intermolecular hydrogen bonds depicted as in Fig.2.C-H� � ��(ring) interactions are depicted by green dashed lines and non-interacting hydrogen atoms are omitted for clarity.

Figure 7
Figure 7Synthesis of the title compound.

Table 2
Experimental details.