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Reactions of Heterocyclic β -Enamino Esters Synthesis of Pyranopyrimidine, Pyranopyridine, and N-(Pyran-2-yl)azetidinone Ring Systems

A. A. Fadda, M. A. Hanna, and M. M. Girges

Department of Chemistry, Mansoura and Damiatta Faculties of Science, Mensoura University, 355 16 Mansoura, Egypt


Abstract: Reaction of 2-amino-5-cyano-3-ethoxycarbonyl-4-(p-methoxyphenyl)-6-phenyl-4H-pyran (β-enamino ester) with phenyl isothiocyanate, malononitrile, and amides afforded the corresponding pyranopyrimidine derivatives, respectively. Acetylation of β-enamino ester yielded the N-acetyl derivative which reacted with phenacyl bromide to give 2-[N-acetyl-N-(benzoylmethyl)-amino]-5-cyano-3-ethoxycarbonyl-4-(p-methoxyphenyl)-6-phenyl-4H-pyran. Treatment of this compound with sodium hydride in dry toluene gave 8-(benzoylmethyl)-3-cyano-5-hydroxy-4-(p-methoxyphenyl)-7-oxo-2-phenyl-7,8-dihydro-4H-pyrano[2,3-b]pyridine. Cycloaddition reaction between Schiff bases of enamino ester and chloroacetyl chloride in the presence of triethylamine produced the substituted β-lactam ring structures, e.g. 4-aryl-3-chloro-N-[5-cyano-3-ethoxy-carbonyl-4-(p-methoxyphenyl)-6-phenyl-4H-pyran-2-yl]-2-azetidinones. The structure of the hitherto prepared compounds was confirmed by spectral data and, whenever possible, by alternative synthetic routes.

Full paper in Portable Document Format: 464a244.pdf


Chemical Papers 46 (4) 244–248 (1992)

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