Flavonoids, including flavones, flavanones, flavanols, and isoflavones, are an important type of plant polyphenols. The range of available flavanones includes (±)-pinostrobin (1), isolated from balsam poplar Populus balsamifera L. 1 The compound 1 has been shown to possess antiproliferative, 2 antimicrobial, 3 neuroprotective, 4 and anti-inflammatory 5 proper-ties. The development of methods for chemical modification of pinostrobin (1) opens new possibilities for creating new compounds with specific biological activity. Our attention was drawn to the possibility to obtain functionalized chalcones from pinostrobin (1) and to perform subsequent transforma-tions in order to build hybrid structures, in particular com-pounds that would combine both chalcone and coumarin fragments.Modified chalcones are of interest for the creation of new drugs against various types of oncological and viral diseases, as well as diabetes. 6 Coumarin-chalcone hybrids have been previously characterized with regard to antimicrobial, 7 antitumor, 8 and anti-inflammatory 9 activity. Structure-activity studies have provided data about the effect of substituents in the chalcone and coumarin fragments on the selectivity of cytotoxic activity with regard to human tumor cells. 8 The analysis of a library of coumarin derivatives, conjugated with 1,2,3-triazole ring at positions 3, 10 4, or 7 11,12 of the coumarin system, showed that triazole ring is an important structural feature for the creation of selective antitumor agents -inducers of tumor cell apoptosis and specific inhibitors of the G2 phase in cell division. Besides that, 1,2,3-triazoles were characterized as potential inhibitors of PDE4В phosphodiesterase, which reduced the proliferation of lung cancer cells and inhibited their angiogenesis. 13 For these reasons, we were interested in the synthesis and study of coumarin-chalcone hybrids containing a 1,2,3-triazole linker. Our objective was to develop a method for the preparation of 2-(bromoalkoxy)-and related 2-(azidoalkoxy)chalcones from pinostrobin (1) and to investigate the possibilities for using these new azides in the synthesis of coumarin-chalcone hybrids.The reaction of pinostrobin (1) with dihaloalkanes (1,4-dibromobutane (2), 1,5-dibromopentane (3), or 1,6-dibromoThe reaction of flavanone pinostrobin with dibromoalkanes in acetone in the presence of potassium carbonate followed the path of retroMichael addition -О-alkylation and resulted in the formation of the respective 2-(bromoalkoxy)chalcones. Treatment of the latter with sodium azide gave the respective azides, which were highly active in the Сu-catalyzed 1,3-dipolar cycloaddition reaction. The reaction of these azides with 6-substituted 7-ethynylcoumarins gave coumarin-chalcone hybrids containing a 1,2,3-triazole linker.
