The present thesis has two major subjects; the synthesis of i) mephedrone derivatives and ii) the key fragment of leoligin and leoligin analogs. i) Methcathinones are widely used recreational drugs. These inhibitors of monoamine transporters are typically consumed as racemic mixtures. One of the most commonly used methcathinones is mephedrone. In this work, racemic mixtures as well as enantiomerically pure samples of representative mephedrone derivatives were prepared. Therefore, different strategies were employed. ii) Leoligin, the major lignan from Leontopodium nivale ssp. alpinum, is capable of enhancing macrophage cholesterol efflux, suppression of the NFB pathway, and inhibition of intimal hyperplasia. For this reason, it is a molecular scaffold from which physiologically useful compounds may be developed for the prevention of atherosclerosis and treatment of restenosis in the wake of bypass grafting and angioplasty. This work is based on a previously developed approach, which permitted the synthesis of a sufficiently diverse array of leoliginlike compounds to selectively improve on the biological activities of this plantderived natural product. All these compounds have one fragment in common, which is synthesized within this work for further modifications.