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All stereoisomers of lariciresinol were synthesized to examine the effect of stereochemistry on plant growth. Configuration of benzylic 7-positions was constructed through S(N)1 or S(N)2 intramolecular etherification. 8- and 8'-position configurations were established from the starting material except for all cis stereoisomers, the 8-position configurations of which were achieved by employing stereoselective hydroboration. (-)-Lariciresinol and its 7S,8S,8'R stereoisomer inhibited the root growth of Italian ryegrass to 51-55% relative to the negative control, whereas other stereoisomers had less effect. These results demonstrate that the stereochemistry of lignans is one of the important factors influencing their inhibitory activity.

All stereoisomers of 3,3'-dimethoxy-7,7'-epoxylignane-4,4'-diol were synthesized to examine the effect of stereochemistry on their plant growth inhibitory activity using lettuce and Italian ryegrass. The effect of structural modifications such as dehydroxylation, methoxylation and hydroxylation at the 9- and 9'-positions of the lignans on the activity was also studied. Most of the epoxylignanes showed higher plant growth inhibitory potency against ryegrass than against lettuce, and the inhibitory activity varied depending on the configurations of each position of the tetrahydrofuran ring (7-, 7'-, 8-, and 8'-positions of the epoxylignanes). Among the 9,9'-position-modified derivatives, the dehydroxy derivatives showed the highest potency. These results suggested that the plant growth inhibitory activity should be influenced by the structure of the epoxylignanes.

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The influence of an F-atom in the side chain of benzo[7]annulen-7-amines on the affinity towards GluN2B subunit containing NMDA receptors and the selectivity over related receptors was investigated. The synthesis of and was performed by reductive amination of the ketone with primary alkanamines and bearing an F-atom in β-position. The GluN2B affinities of non-fluorinated and fluorinated ligands and are almost identical. The low impact of the F-atom on GluN2B affinity was unexpected, as it influences several chemical and physicochemical properties of the ligands. However, introduction of the F-atom led to reduced selectivity over receptors. Whereas and display still a 2-3-fold preference for GluN2B over receptors, they show almost the same affinity to GluN2B and receptors.