title: Efficient synthesis of 1,2-bis(alkoxycarbonyl)pyrazol-3-ones from 2,3-allenoic acids, azodicarboxylates and PPh3.
abstract: An efficient cascade reaction of 2,3-allenoic acids with dialkyl azodicarboxylate in the presence of PPh3 affording 1,2-bis(alkoxycarbonyl)pyrazol-3-ones in moderate yields has been developed. The reaction may proceed via the intramolecular Michael addition of the expected 2,3-allenoyl hydrazines.
authors.affiliation: Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, 3663 North Zhongshan Lu, Shanghai 200062, Peoples Republic of China. masm@sioc.ac.cn.
authors.forename: Ruizhi
authors.initials: R
authors.lastname: Lü
authors.forename: Xin
authors.initials: X
authors.lastname: Cheng
authors.forename: Xingliang
authors.initials: X
authors.lastname: Zheng
authors.forename: Shengming
authors.initials: S
authors.lastname: Ma
mesh_terms: D001386:Azides / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D003500:Cyclization; D006834:Hydrazines / Q000737:chemistry; D008958:Models, Molecular; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001386:Azides; D002264:Carboxylic Acids; D006834:Hydrazines; D011720:Pyrazoles