The Reseach On Novel Acylation And Methylation Reactions

Acylation and methylation are crucial research fields in synthetic chemistry, and are widely applied in pharmaceutical synthesis, fine chemicals, and food additives.Over the past few decades, acylation and methylation have gained much attention of organic synthesis chemists, and made great progress and development. Based on the previous works in this area, we wish to disclose our recent development on their further applications in synthetic organic chemistry.This dissertation is made up of three chapters:Chapter one is about concise synthesis of semicarbazides and formylhydrazines via direct addition reaction between aromatic azoarenes and N-substituted formamides.Selective cleavage of the N-substituted formamides will afford the N-formylated products and hydroacylated products in the presence of Na I/DTBP and imidazole/DCP catalytic systems, respectively.Chapter two is about a practical, chemoselective approach to O-methylation of carboxylic acids with dimethyl malonate. In this work an efficient and practical method for the O-Methylation of carboxylic acids has been developed by utilizing a new inexpensive and low toxic methylating reagent, dimethyl malonate. The protocol was proved to tolerate various carboxylic acids, and with excellent chemoselectivity.Chapter three is about temperature-controlled Na I-mediated α-oxyacylation or oxidative decarboxylative coupling of dimethyl malonate with carboxylic acids. We described a facile Na I-mediated oxidative coupling of dimethyl malonate with carboxylic acids. Two types of products resulting from different reaction routes have been obtained, depending on distinct reaction temperatures that were employed.