New Synthetic Reactions Using Conjugate Addition Reactions of Active Methine Compounds to Alkynyl Imines and Ketones

摘要

The development of the synthetic methods of functionalized 2-pyridones is important as a result of the large number of biologically active compounds containing a 2-pyridone structure and as dienes in Diels-Alder cycloadditions.Many methods for the synthesis of 2-pyridones have been reported.We have found a 5-alkoxycarbonyl-2-pyridone synthesis via the nucleophilic addition of malonic esters to alkynyl imines in good yields.It is also found that the reaction of beta-keto esters with alkynyl imines give 5-acetyl-2-pyridones in good yields.On the other hand,the reactions of dialkynyl imines instead of alkynyl imines with active methine compounds give 3,4,5,6-tetrasubstituted-2-pyridones.We have found that the reactions of alkynylpyridines,pyrimidine,or thiazoles with malonic esters give bicyclo-2-pyridones in moderate to good yields.The conjugate addition reactions of various cyclic beta-keto esters with alkynyl imines proceed and then the intramolecular cyclization reactions take place.The subsequent cleavage reactions give two-atom enlarged carbocyclic products in good yields.We have also found the reactions of malonic esters or beta-keto esters with alkynyl ketones give 5-alkoxycarbonyl-2-pyrones or 5-acetyl-2-pyrones in good yields.