Subscribe to RSS
DOI: 10.1055/s-2007-968681
Synthesis of a New Class of Pyrido[2,3-d]pyrimidine Derivatives
S. Tu*, J. Zhang, R. Jia, B. Jiang, Y. Zhang, H. Jiang
Xuzhou Normal University, Jiangsu, P. R. of China
Publication History
Publication Date:
22 June 2007 (online)
Significance
An efficient synthesis of pyrido[2,3-d]-pyrimidine-4,7-diones having a seldomly investigated C-6 hydroxyiminoethyl or benzamido substituent pattern is reported. This interesting heterocyclic interconversion is proposed to involve three key steps: Michael addition of the 2,6-diamino-pyrimidinone or naphthalen-2-amine to the 4-arylidene-3-methylisoxazolone or the 4-arylidene-2-phenyloxazolone forming a new C-C bond, followed by acid-catalyzed heteroannulation and opening of the oxazolone or isoxazolone ring. Highest yields were observed when a 2:1 volume ratio of DMF and glacial acetic acid was employed, with the latter acting as both solvent and catalyst. Exclusive formation of the trans diastereoisomers was observed in good yields, with a broad substrate scope.