Carbamate In The Synthesis Of Heterocyclic Compounds

Nitrogen-containing heterocyclic compounds have been widely used in medicine, pesticide and other fields. In the paper, some methods for preparing nitrogen-containing heterocyclic compounds are provided. Trizolones, pyrroles and oxazines are synthesized by using carbamic esters as initiative materials.Three methods for the preparation of 1,2,4-trizolone~5 are provided. 22 compounds are prepared. 3, 4-disubstituted 1,2,4-trizolone-5 is prepared by reacting amide with ethyl hydrazine-fornate at 110癈 for 3h in the presence of phosphorus oxychloride, following neutralization and cyclization reaction, giving to 74.5 % yields ( in total ),which is 30% more than the literature value.N-substituted pyrroles are synthesized by reacting acetonylacetone with carbamic ester , catalysted by p-toluenyl sulfonic acid, heated at reflux temperature for 6h, collecting evolved water, giving to 75% yields, which is 26% more than the literature value.6-methyl-l, 3-oxazine-2,4-dione are prepared from ethyl acetoacetate and ethyl carbamate at 140 for 6h, catalysted by zinc acetate, giving to 48.8% yields which is 33% more than the literature value.