tert-Butyl N-[3-hydroxy-1-phenyl-4-(pyrimidin-2-ylsulfanyl)butan-2-yl]carbamate monohydrate

In the title hydrate, C19H25N3O3S·H2O, the configuration at each chiral centre in the organic molecule is S, with the hydroxy and carbamate substituents being anti [O—C—C—N torsion angle = −179.3 (3)°]. The thiopyrimidyl and carbamate residues lie to one side of the pseudo-mirror plane defined by the C5S backbone of the molecule; this plane approximately bisects the benzene ring at the 1- and 4-C atoms. The dihedral angle formed between the terminal rings is 5.06 (18)°. In the crystal, supramolecular tubes aligned along the b axis are found: these are sustained by a combination of O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds.

In the title hydrate, C 19 H 25 N 3 O 3 SÁH 2 O, the configuration at each chiral centre in the organic molecule is S, with the hydroxy and carbamate substituents being anti [O-C-C-N torsion angle = À179.3 (3) ]. The thiopyrimidyl and carbamate residues lie to one side of the pseudo-mirror plane defined by the C 5 S backbone of the molecule; this plane approximately bisects the benzene ring at the 1-and 4-C atoms. The dihedral angle formed between the terminal rings is 5.06 (18) . In the crystal, supramolecular tubes aligned along the b axis are found: these are sustained by a combination of O-HÁ Á ÁO, O-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds.
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil).

Comment
Compounds having a hydroxyethylamine core play important roles in the medicinal chemistry field. They inhibit aspartyl protease enzymes and are widely used as anti-HIV agents (Brik & Wong, 2003;Ghosh et al., 2001), as inhibitors of BACE-1 to combat Alzheimer's disease (Marcin, et al., 2011) and have also been considered in the treatment of leishmania/HIV-1 co-infections (Trudel et al., 2008). Cunico and co-workers have reported on the in vitro activity of hydroxyethylamine derivatives as anti-malarial agents (Cunico et al., 2009a(Cunico et al., , 2009b(Cunico et al., , 2009c(Cunico et al., , 2011 and in this article we report the structure of the title molecule, isolated from ethanol solution as a monohydrate, (I).
The structure analysis of (I) confirms the stereochemistry at each of the C1 and C7 atoms to be S, Fig. 1, as anticipated from the synthesis. The O1 and N3 substituents on C1 and C7, respectively, have an anti disposition [the O1-C1-C7-N3 torsion angle = -179.3 (3) °]. With reference to the C 5 S backbone of the molecule, i.e. comprising the C1/C2/C7/C13/C14/S1 atoms, the benzene ring occupies a position that is approximately bisected by the pseudo mirror plane through these atoms [the C7-C13-C14···C17 torsion angle = -17.1 (5) °] whereas the thiopyrimidyl group lies to one side of the plane [the C3-S1-C2-C1 torsion angle = 89.9 (2) °]. The terminal rings of the C 5 S backbone are almost parallel forming a dihedral angle of 5.06 (18) °. The carbamate residue lies to the same side of the C 5 S plane as does the thiopyrimidyl group with the t-BuO atoms being directed away from the rest of the molecule.
In the crystal, the water molecules serve to link translationally related hydroxy groups by forming both donor and acceptor interactions, and at the same time the water molecule forms a donor interaction to one of the pyrimidyl-N atoms, Table   1. The resultant supramolecular assembly, a tube, is further stabilized by amine-H···O(carbonyl) interactions. Side-on and end-on views of the supramolecular tube are shown in Figs 2 and 3, respectively. The tubes are aligned along the b direction as seen in Fig. 4.
The O-and N-bound H atoms were located from a difference map and refined with the distance restraints O-H = 0.84 ± 0.01 and N-H = 0.86±0.01 Å, and with U iso (H) = zU eq (carrier atom); z = 1.5 for O and z = 1.2 for N. Fig. 1. The molecular structure of (I) showing displacement ellipsoids at the 50% probability level.