Structure--taste relationship of perillartine and nitro- and cyanoaniline derivatives

The relationship between structure and taste potency of perillartine and its analogues was investigated quantitatively by physicochemical parameters and regression analysis. The results indicated that the hydrophobicity estimated from the 1-octanol/water partition coefficient and the molecular widths from the bond axis connecting the oxime carbon and alicyclic ring are important, regardless of whether the taste is sweet or bitter, so far as the taste potency is concerned. The SAR for the sweet/bitter ratio was not established quantitatively, but the molecular width and thickness and the position-specific electronic effect seem to delineate the ratio qualitatively; i.e., in principle, the wider and/or the thicker the molecule, the more bitter the taste. Comparatively, the QSAR of 5-nitro- and 5-cyanoaniline sweetners was formulated to show the insignificance of the hydrophobicity within the compounds investigated but the importance of the steric dimensions in determining the activity.