(1S,3R)-N-{(3S,10S,12S,13R,17R)-12-Hydroxy-17-[(R)-5-hydroxypentan-2-yl]-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-yl}adamantane-1-carboxamide 0.25-hydrate

The title compound was synthesized from deoxycholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain.

The title compound, C 35 H 57 NO 3 Á0.25H 2 O, was synthesized from deoxycholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain. The compound crystallizes in the P1 space group with four steroid molecules and one water molecule in the triclinic cell unit. The crystal structure features O-HÁ Á ÁO hydrogen bonding. The crystal studied was refined as a non-merohedral twin.

Structure description
Bile salts are natural surfactants with a diverse biological activity, some of their derivatives show antiproliferative, antimicrobial and anticancer activity (Huang et al., 2009). Lately new compounds have been synthesized with a hydrophobic expansion in the region 3 (Monte et al., 2009); as a result, interesting supramolecular properties arise and some of them show cytotoxic activity (Trillo et al., 2014). Hydrophobic derivatives of bile acids have been demonstrated to exhibit biological activity against certain cells; these derivatives cause apoptosis (programmed cell death), throughout a series of biochemical reactions inside the cellular body.
For inclusion crystals of 3,7,24-tetrahydroxycholane with aromatic compounds, see: Liu et al. (2013). For the inclusion abilities of cholic acid and its derivatives, see: Sada et al. (1994). For the lamellar structure formed by an adamantyl derivative of cholic acid, see: Soto et al. (2006).

data reports
There are four independent molecules, which do not show any significant differences, and one water molecule in the asymmetric unit of the title compound ( Fig. 1), which crystallizes in space group P1. The crystal structure features extensive O-HÁ Á ÁO hydrogen bonding (Table 1, Fig. 2), leading to the formation of a two-dimensional network parallel to (010).

Synthesis and crystallization
The compound was initially obtained by the coupling of methyl 3-aminodeoxycholate with adamantane-1-carbonyl chloride. Subsequently and after deprotecting the 24 position, the acid group was reduced with borane. The synthesis followed previously published methods (Trillo et al., 2014).

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The title compound crystallized as a non-merohedral twin (determined with CELL_NOW; Sheldrick, 2008a) and an approximate ratio between the domains of 52:48% (determined with the refinement against hkl5 file). The data were integrated using the two orientation matrixes and TWINABS (Sheldrick, 2012) was used to generate the merged hkl4 file that contained only non-overlapped reflections belonging to the first domain and an hkl5 file containing single and overlapped reflections for both domains. As the refinement against the merged hkl4 file gave better results, it was selected over the hkl5 refinement. In case of H1N_1 and H1N 0 _1, FLAT 0.3 was used to keep the disordered protons close to the plane of the corresponding position of the disordered HN-C(O) peptide bond. The disordered groups (residue 1: HN-C(O), residue 4: adamantane carbonyl group) were refined using geometry (FLAT, SADI and SAME) and U ij restraints (SIMU and RIGU) implemented in SHELXL (Sheldrick, 2015b). Noteworthy, Q1 (0.32 e À Å À1 ) corresponds to a second position of the OH group of residue 4 that does not modify appreciably Table 1 Hydrogen-bond geometry (Å , ).  (6) 165 (8) Symmetry codes: (i) x þ 1; y; z þ 1; (ii) x; y; z À 1.

Figure 1
One of the four molecules in the asymmetric unit of the title compound; disordered atoms (N1, O3, C25-C33) and the water molecule are omitted for clarity.

Special details
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. Carbon-bound hydrogen atoms were placed in idealized positions and refined with a riding model. N-H hydrogen atoms were localized from the residual electron density map and refined with Uij tied to the parent atom with distance restraints.  0.050 (2) 0.051 (2) 0.047 (2)