Study On The Synthesis Of New Types Of Pyrrole Derivatives

In this paper β-carbonyl O-methyloxime derivatives were prepared from acetylacetone and ethyl acetoacetate. 4-Bromo-2-butenoate, 1,4-dibromo-2-butene and some β-carbonyl O-methyloxime derivatives were prepared according to literature procedures. The synthesis of methyl 4-bromo-2-butynoate was improved.The intramolecular Michael addition occurred simultaneously when α-alkylation of β-carbonyl O-methyloximes was carried out with methyl 4-bromo-2-butynoate or 4-bromo-2-butenoates, and corresponding pyrrole or dihydropyrrole derivatives were obtained respectively.The intramolecular cyclization occurred with the catalysis of palladium dichloride after α-alkylation of acetylacetone O-methyloxime with 1,4-dibromo-2-butene, and corresponding dihydropyrrole was obtained in two steps.