title: An efficient method for the construction of polysubstituted 4-pyridones via self-condensation of β-keto amides mediated by P2O5 and catalyzed by zinc bromide.
abstract: A self-condensation cyclization reaction mediated by phosphorus pentoxide (P2O5) and catalyzed by zinc bromide (ZnBr2) is presented for the synthesis of polysubstituted 4-pyridones and 2-pyridones from β-keto amides. A variety of β-keto amides are used in this approach, and a wide range of functionalized 4-pyridones and 2-pyridones were obtained in good to excellent yields. When employing the N-aryl β-keto amides as the substrates in this protocol, 4-pyridones are resulted, however, when using N-aliphatic-substituted β-keto amides as the partners of N-aryl β-keto amides under the same conditions, 2-pyridones are afforded.
authors.affiliation: School of Chemistry and Life Science, Guangdong University of Petrochemical Technology, 2 Guangdu Road, Maoming 525000, China.
authors.forename: Liquan
authors.initials: L
authors.lastname: Tan
authors.affiliation: School of Chemistry and Life Science, Guangdong University of Petrochemical Technology, 2 Guangdu Road, Maoming 525000, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.affiliation: School of Chemistry and Life Science, Guangdong University of Petrochemical Technology, 2 Guangdu Road, Maoming 525000, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Chen
authors.affiliation: School of Chemistry and Life Science, Guangdong University of Petrochemical Technology, 2 Guangdu Road, Maoming 525000, China.
authors.forename: Weibing
authors.initials: W
authors.lastname: Liu
keywords: 2-pyridones; 4-pyridones; phosphorus pentoxide; self-condensation; β-keto amide