(±)-3-Benz­yloxy-1-(4-meth­oxy­benz­yl)piperidine-2-thione

The title mol­ecule, C₂₀H₂₃NO₂S, adopts a twisted conformation in which the two aromatic rings connected to the central piperidine ring are orientated trans to each other. An intra­molecular C—H...S contact occurs. In the crystal, C—H...π and C—H...O inter­actions act to stabilize the structure in three dimensions.

3-Hy­droxy-1-(4-meth­oxy­benz­yl)piperidin-2-one

The title compound, C₁₃H₁₇NO₃, adopts a conformation in which the aromatic ring and the mean plane of the piperidine ring are almost perpendicular to each other [dihedral angle = 79.25 (6)°]. The presence of the carbonyl group alters the conformation of the piperidine ring from a chair to a twisted half-chair conformation. In the crystal, pairs of strong O—H...O hydrogen bonds link the mol­ecules into inversion dimers. Weak C—H...O inter­actions extend the hydrogen-bonding network into three dimensions.

(Z)-Ethyl 2-hy­droxy-4-oxo-4-(1,4,5,6,8-penta­meth­oxy­naphthalen-2-yl)but-2-enoate

The title compound, C₂₁H₂₄O₉, crystallizes with two independent mol­ecules in the asymmetric unit which are almost centrosymmetrically related to each other. The ethano­ate group in one of the two mol­ecules is disordered over two positions with a site-occupation factor of 0.880 (7) for the major occupied site. In the crystal, the 1,3-diketone group exists in the keto–enol isomeric form due to the stabilizing effect of the intra­molecular O—H...O hydrogen bond present in this form. The compound packs as a layered structure in which C—H...π and C—H...O inter­actions are present within and between the layers.