| Резюме: |
The main goal of the present dissertation was to investigate the chemical behavior of diethyl ester of coumarin-3-phosphonic acid 1a with organometallic reagents in reactions carried out under different reaction conditions - conventional and ultrasonic irradiation conditions. Based on the obtained results some conclutions for the chemical behavior of 1a were made: Under conventional reaction condition (reflux), the reaction with organomagnesium reagents proceeded easily as 1,4-addition - the corresponding products were isolated with 38-78% yields. The main disadvantage of the method was the lack of reproducibility of the results. The Michael-type addition proceeded with better yields (53-94%) and shorter reaction times when ultrasonic irradiation was applied, another advantage of the sonocation method was the increased reproducibility of the obtained results - average statistical deviation of the yields 0.8-1.5%. As a result of the reaction of 1a with chloroacetic anhydride in the presence of zinc under ultrasound conditions, the dimer tetraethyl(2,2'-dioxo-4,4'-dichroman-3,3'-diyl)bisphosphonate was isolated and characterized.A new convenient method for dimerization of 3-substituted coumarins with the use of ultrasonic radiation had been developed and the products were obtained in 45-92% yields. It was noted that the homodimerization reaction is applicable only to coumarins with an electronacceptor group in the 3-rd position. Based on the obtained results, an assumption for the mechanism of the dimerization reaction was made.
|