WITTIG REACTION AS A PROMISING METHOD OF THE CHALCONES OBTAINING

Abstract

Chalcones, being the derivatives of 1,3-diphenylpropenone and its analogues are of interest primarily due to the wide spectrum of their physiological activity. The therapeutic properties of a number of plant origin natural compounds of this class caused an active preparation and investigation of their synthetic analogues. Particularly chalcones show high anti-inflammatory, antibacterial and antiviral, as well as antitumor and antihyperglycemic activity. They are also characterized by valuable optical properties, fluorescent by instance. Chalcones are also known as valuable intermediates for the synthesis of other classes organic compounds, primarily heterocycles. A wide range of practically valuable properties requires an active search for new ways of their synthesis. The Wittig reaction as a method for obtaining chalcone derivatives has been known for a long time, but its capabilities and application options in this area have not been studied sufficiently. Current investigation aims to obtain new chalcones on the base of aldehydes containing ester groups in their molecules as well as to study the possibility of phosphonium salts application as starting compounds, without intermediate isolation of alkylidenephosphoranes. It have been found that phosphonium salts easily interact with aldehydes in the presence of triethylamine, the action of the base converts the salt into alkylidenephosphorane, which under reaction conditions immediately interacts with the aldehyde, forming the corresponding unsaturated ketones. This method allowed to obtain a number of hydroxychalcones, benzoxazinone derivatives and heterocyclic analogues of chalcones. However, the mentioned synthesis method have been found to be unavailable for compounds containing sensitive to alkaline hydrolysis groups. In this case it turned out to be necessary to use alkylidenephosphoranes previously isolated in an individual state. A number of substituted chalcones, particularly those containing fragments of natural compounds – coumarin and pyridinecarboxylic acids – have been obtained by interaction of stable phosphorylides with aldehydes containing ester groups.