(+)-Cedrol hemihydrate: a natural product derived from drying eastern red cedar (Juniperus virginiana) wood.

Cedrol-like compounds are of pharmacological interest due to their diverse range of medicinal effects and are used globally in traditional medicines and cosmetics. Many cedrol tautomers are known from molecular studies but few have been studied in crystalline form by X-ray diffraction. Acicular white crystals collected from the wood of eastern red cedar (Juniperus virginiana) are determined to be (+)-cedrol hemihydrate, namely, (1S,2R,5S,7R,8R)-2,6,6,8-tetramethyltricyclo[5.3.1.0^1,5]undecan-8-ol hemihydrate, C₁₅H₂₆O·0.5H₂O, a novel packing of two unique cedrol molecules (Z' = 2) with a single water molecule [space group P2₁2₁2₁; a = 6.1956 (1), b = 14.5363 (1), and c = 30.9294 (4) Å]. The hydrogen bonding forms a one-dimensional spiral chain running along the a axis, following the chirality of the cedrol molecule, through hydrogen-bonding interactions with a right-handed helical configuration in graph-set notation Δ-C₃³(6) > a > c > b. The crystal packing and symmetry are different from crystalline isocedrol due to the different hydrogen-bonding geometry.