Synthesis Of Nitrogen-containing Heterocycles And Their Boron Complexes

In recent years,much attention has been paid to the luminescent boron complexes.For the organic molecules that can act as chelating ligands,the boron complexation is a simple yet effective strategy to express or enhance fluorescence.This thesis is devoted to the exploration of the strategies for the synthesis of nitrogen-containing heterocycles that can potentially be used as chelating ligands for the boron complexation.Furthermore,the synthesis and the optical properties of some N,O-chelated boron complexes were also studied.Chapter 1 deals with a catalyst-free protocol for the reaction of 2-methylazines and aryl glyoxal hydrates leading to ?-hydroxy ketones bearing azaarene moiety.The developed process proved to be operationally simple and was applied to a broad range of substrates.A possibility to prepare N,O-ligands suitable for boron complexation is discussed.Chapter 2 focuses on a copper(II)triflate-catalyzed diethylamine-assisted protocol for the reaction of 2-aminonicotinaldehydes and terminal alkynes leading to 1,8-naphthyridines.The overall process presumably involves a copper(II)triflate-catalyzed hydroamination of the triple bond followed by the Friedl?nder-type condensation of the resulting enamine with 2-aminonicotinaldehyde.In the Chapter 3 we have prepared a series of N,O-chelated azine-enol boron complexes featuring a different conjugation pattern of the benzene ring in the azine fragment.The optical properties of these complexes were studied in dichloromethane solution and in solid state.