Investigations On Palladium And Copper Catalyzed Desulfurative Coupling And Domino Reactions Of Dihydropyrimidinthione/thioethers

Recently, desulfurative coupling reactions of organosulfur compounds attracted wide attetion from the organic synthesis field. Compared with the other bonds in organic molecules, C-S bonds possess the virtues of higher reactivity for their lower bond-energies, and their strong tendencies to cordinate the transition metals. Organosulfur compounds are widely rooted in the natural circulation, endowed us with broad access to these synthetical materials. Above all, it is undoubtedly a valueable research on the desulfurative coupling reactions of organosulfur compouds as dihydropyrimidinthiones(DHPM).It was mainly discussed in this thesis the recent advances reported about desulfurative coupling reactions with a brief review. Then, the cleavage of C-S bonds of the dihydropyrimidinthiones(DHPM)(or thioethers) with the formation of new C-C bonds were investigated. In company with these experiments, a domino desulfurative coupling-acylation-hydration-Michael addition cycling process was revealed. A series of melecules of pyrimidine derivatives were synthesized, providing the new methods for the synthesis of this class of organic compounds with their structural units expanded. The contents of this thesis include:1. A brief review of the recent advances reported about desulfurative coupling reactions.2. With Palladium(II) and copper(I) as catalyst, a multiple-component domino reaction process in one pot among dihydropyrimidinthiones(DHPM), carboxylic acids and terminal alkynes was investigated. A series of pyrimidine derivatives were synthesized as products. C-C coupling, hydration of the alkyne, amide formation and Micheal addition were completed simultaneously in the domino process, with a molecule with pyrido[1,2-a]pyrimidine scafold produced. The reaction was easy hadling and operating, and substrates were tolerated well.3. With Palladium(II) and copper(I) as catalyst, a multiple-component domino reaction process in one pot among 2-(phenylthio)-1,4-dihydropyrimidine, carboxylic acids and terminal alkynes was investigated. The transformations of 2-(phenylthio)-1,4-dihydropyrimidine derivatives were similar to that of the DHPM, with the same domino process of C-C coupling, hydration of the alkyne and amide formation revealed.4. With Palladium(II) and copper(I) as catalyst, reactions between 2-(ethylthio)pyrimidine and terminal alkynes was investigated. This is a C-C coupling reaction between thioether derivatives and terminal alkynes, with a series of 2-(alkynyl)pyrimidine derivatives produced.A series of pyrimidine derivatives were synthesized in those processes above, with their structures characterized by 1H NMR、13C NMR、HRMS analysises.