Aza-and carba-Michael Adducts as Building Blocks in Heterocyclic Synthesis

Abstract

The present work deals with the reaction of 4-(4-bromo phenyl oxobut-2-enoic acid 1 with nitrogen and carbon nucleophiles afforded aza-and carb-Michael adducts 2, 3, 6, 9, 10, 11, 12, 13, 14 depending on the type of reagents and medium (neutral or basic) . The adducts 2 are used as a key starting materials to synthesize some hetrocycles include furanone 15, oxazinone 16 and pyridazinone 17 derivatives .The behavior of the latter compounds towards different electrophilic and nucleophilic reagents were investigated.Hydrazinoysis of the carba- Michael adduct 6 afforded tetrahydrobenzo1,2-diazapene derivatives 7, 8. The structure of the newly synthesized compounds were elucidated by elemental analysis and spectroscopic data