QSAR for Cycloaliphatic Alcohols with Qualitatively Defined Sandalwood Odour Characteristics

QSAR's are set up for a series of up to 53 cycloaliphatic alcohols with qualitatively defined sandalwood odour characteristics: i-inactive, w-weak, s-strong, and vs-very strong. “Central” values (0, 1, 2, and 3) were attached to these qualitative characteristics, as well as intervals (<0.5; 0.5–1.5; 1.5–2.5; >2.5). The superposition procedure of the MTD method was used to define the probable active conformation. Conformational energies and log Poct values were also calculated using HyperChem-2 and Chemicalc-2. A correlational equations were set up using δ, D and D2–with δ=1 for OH groups in favourable position and D–the distance between the gravity centre of the hydrophobic moiety and the osmophoric OH-group. The MTD method was used only for a series of N=15 rigid molecules, because a too large number of vertices for the whole series appear. Eighter central values or intervals were used as biologic activities. The δ, D and D2–equations set up for N=31 molecules allow a good classification of the training set and also of the rest of molecules, considered as test set. An osmophoric receptor with a hydrophylic part (2 or 3 OH-groups) and a relatively large hydrophobic pocket is suggested, which produces also some steric misfit with regard to these molecules.