Synthesis Of2-methyl-oxazole Derivatives And α-Carbonyl Ester By Gold Catalysis

Homogeneous gold catalysis has attracted much attention lately owing to theexceptional capacity of gold complexes/salts in activating alkynes and allenes towardnucleophilic attack. A variety of practically useful synthetic methods using alkyne orallene substrates have been developed. Further reviews and highlights on Au catalysisfocus on particular classes of synthetic reactions.Thanks to gold-basedcatalysts,various organic transformations have been accessible under facile conditionswith both high yields and chemoselectivity.The oxazole ring with its2-and5-positions substituted with aryl or alkyl groupsis an important structure found in various natural products and compounds withbiological activities. these oxazoles can also serve as versatile substrates for varioussynthetic transformations,including the formation of fully substituted oxazoles.Therefore, synthesis of2,5-disubstituted oxazole derivatives have very importantsignificance.First，a series of2-methyl-oxazole derivatives were successful synthesized,which by using Ph₃PAuNTf₂as a catalyst for the reactions,which used erminalalkynes and acetonitrile as the reaction substrate. The reactions carried on in verymild conditions: at room temperature for three hours. In the reaction, acetonitrile isnot only as the reaction substrate but also as the reation solvent, at the same time,8-methylquinolinenitrogen oxygen is the oxidant of the reaction. Compared with otherways of synthesizing2,5-disubstituted oxazoles derivatives, gold catalysis has itsunique advantages, which they can carry on in the mild conditions,as well，they have avariety of reaction substrates and so on.Then，antibacterial activity of2-methyl-oxazole derivatives was carried on withstaphylococcus aureus、 table staphylococcus aureus、 escherichia coli andpseudomonas aeruginosa by dilution method.which showed that the2-methyl-oxazolederivatives could be a fairy good bacteriostatic reagent.α-carbonyl ester，the intermediate product of many organic reactions, plays avery important role of a bridge in the process of organic synthesis and industrialproduction, due to its importance for the research and synthesis. This class ofsubstances were synthesized by using gold catalysis in the experiment,the synthesis ofα-carbonyl ester by gold catalysis as a groundbreaking method of synthesis, had aextremely progressive significance to α-carbonyl ester.During the experiment, by Comparative experiment, selected the gold catalyst and oxidant of the reaction, andthen got the optimum reaction conditions, which used Ph₃PAuNTf₂as the catalyst，inaddition，regarded8-methylquinolinenitrogen oxygen as the oxidant of the reaction.During the reaction, a certain amount of MsOH was added. reacted by substrate ofterminal alkyne and acetic acid, which prepared a series of α-carbonyl ester with veryhigh yield. The reaction carried on in mild conditions, as well, fewer subsidiaryreactions happened during the reaction, at the same time, Steped with high yieldsynthesis of the target product.In conclusion, on the one hand, a series of2-methyl-oxazole derivatives andα-carbonyl ester were synthesized. On the other hand, indicate that gold catalysis oforganic reactions has vital significance, and it carried on smoothly in mild conditions,as well, it has a very good yields. A series of target Compounds which weresynthesized during the experiment, are characterized the structure by using¹H NMRand¹³C NMR.