4-{[4-(Hydroxymethyl)piperidin-1-yl]methyl}phenol

In the title compound, C13H19NO2, the piperidine ring has a chair conformation with the exocyclic N—C bond in an equatorial position. In the crystal, molecules are linked head-to-tail by phenol O—H⋯O hydrogen bonds to hydroxymethylene O-atom acceptors, forming chains which extend along [100]. These chains form two-dimensional networks lying parallel to (101) through cyclic hydrogen-bonding associations [graph set R 4 4(30)], involving hydroxy O—H donors and piperidine N-atom acceptors.

In the title compound, C 13 H 19 NO 2 , the piperidine ring has a chair conformation with the exocyclic N-C bond in an equatorial position. In the crystal, molecules are linked headto-tail by phenol O-HÁ Á ÁO hydrogen bonds to hydroxymethylene O-atom acceptors, forming chains which extend along [100]. These chains form two-dimensional networks lying parallel to (101) through cyclic hydrogen-bonding associations [graph set R 4 4 (30)], involving hydroxy O-H donors and piperidine N-atom acceptors.
There are two independent classic hydrogen-bond types involving the phenolic, hydroxymethylene and piperidine groups, contributing to the stability of the crystal packing (Table 1). Translation-related molecules are linked head-to-tail along [001] through phenolic O-H···O hydrogen bonds to hydroxymethylene O-atom acceptors (Fig. 2). This hydroxy group also acts as a donor to the piperidine nitrogen ( Fig. 3), forming two-dimensional sheets which extend across (010).
The morphology of the cyclic H-bond pattern within the sheets is R 4 4 (30) (Etter et al., 1990). No π-π interactions are present in the structure.
Experimental 4-Hydroxybenzaldehyde (0.3 g) and 4-piperidinemethanol (0.27 g) were dissolved in 8.5 mL of methanol. The pH was adjusted to 5 with the addition of acetic acid before the addition of 0.15 g of sodium cyanoborohydride. The system was kept stirred under reflux for 5 h, followed by addition of concentrated HCl (ca. 2 mL) to pH 2.0 and the resulting solution was then basified to pH 12 with solid NaOH. The reaction mixture was extracted with chloroform (3 x 15 mL), and the combined organic phase was subsequently washed with water, then brine, dried over anhydrous sodium sulfate, followed by filtration. However, it was observed that the product was present mainly in the aqueous layer and after a slow    Table 1. For other codes: (iii) x, y, z -1; (iv) x -1/2, -y + 1/2, z + 1/2; (v) x -1/2, -y + 1/2, z -1/2].

Figure 3
The  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.23 e Å −3 Δρ min = −0.16 e Å −3 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 > σ(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.