tert-Butyl 4-{[2-amino-4-(2-hydroxyphenyl)pyrimidin-5-yl]methyl}piperazine-1-carboxylate

In the title compound, C20H27N5O3, the central piperazine ring adopts a chair conformation, with the N-bound carboxylate and methylene substituents occupying bisectional and equatorial orientations, respectively. A twist is evident between the aromatic rings [dihedral angle = 25.61 (9)°] but an intramolecular O—H⋯N hydrogen bond persists between these. Supramolecular tapes along [1-10] are formed in the crystal packing through N(amino)—H⋯O(hydroxyl) and N(amino)—H⋯N(pyrimidinyl) hydrogen bonds, and these are linked into layers in the ab plane by π–π interactions [inter-centroid distance between pyrimidinyl rings = 3.5919 (9) Å].


Comment
Pyrimidine-containing heterocyclic compounds show significant biological importance through various activities such as anti-viral, anti-tumour, anti-proliferative, anti-diabatic, anti-bacterial, etc. (Topalis et al., 2011;Sbardella et al., 2011;Zhang et al., 2011). It was the effectiveness of these derivatives against anti-microbial strains, such as S. aureus and P.
aeruginosa, that motivated the present structural studies of a title compound, (I).
Despite there being a twist between the two aromatic rings in (I), Fig. 1 Fig. 2. Layers in the ab plane are formed by π-π interactions occurring between centrosymmetrically related pyrimidinyl ring [inter-centroid distance = 3.5919 (9) Å for symmetry operation 2 -x, 1 -y, -z], with the layers being associated via hydrophobic interactions, Fig. 3.

Experimental
The title compound, (I), was prepared according to the procedure reported in the literature (Patel et al., 2011). Crystals were obtained by were obtained by slow evaporation from an ethanol solution of (I).

Computing details
Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).  The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 35% probability level.  Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 > 2σ(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.