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Cardanol was obtained by vacuum distillation of ‘‘cashew nut shell liquid’’ (CNSL). Cardanol is a by-product of cashew production and a building block for chemical synthesis; cardanol and its derivatives can be used for different types of applications. Three of these compounds are the subject of the present NMR study and theoretical comparison. 1H and 13C NMR signals were assigned using 1D and 2D NMR experiments. The DFT/B3LYP method using the cc-pVTZ basis set was employed for the calculations of the 1H and 13C NMR chemical shifts (δ). The obtained data were used as an auxiliary tool for unequivocal assignment of all 1H and 1³C NMR signals. For these compounds, the adopted theoretical model was sufficient to obtain a good description of the chemical shifts.

GIAO model at DFT/B3LYP level of theory using the cc-pVTZ basis set was employed for calculations of 1H and 13C NMR chemical shifts (δ) for various rigid polycyclic compounds. The data obtained were used as an auxiliary tool to an unequivocal assignment of all 1H and 13C NMR signals and the endo/exo stereochemistry of the strained compounds studied. For these compounds the theoretical model adopted was sufficient to obtain a good description of chemical shifts.

The direct E/Z configuration assignment of tri- and tetra-substituted stilbenes (and other analogous olefins) when only one of the isomers is available is a quite challenging task. Sometimes, a chemical transformation or some other tedious method is necessary for determination of the double bond substitution pattern. In this paper, we relied on theoretical calculation of chemical shifts as a complementary tool for 1H NMR determination of the configuration of an α-phenylcinnamic acid prepared as a unique isomer by the Perkin reaction.