Pyrido[1,2-a]pyrazine - Startprodukte für regioselektive Ringtransformationen und supramolekulare Architekturen / Pyrido[1,2-a]pyrazines - Starting Materials for Regioselective Ringtransformation Reactions and Supramolecular Architectures

Abstract

The easily available pyrido[1,2-a]pyrazines of type 1 are versatile building blocks for ring transformation reactions.W ith heterocyclic quinones such as quinoline-2,5,8-triones 4a-c, a highly regioselective [4+2]-cycloaddition reaction takes place in the first step, followed by a ring transformation cascade.T he 1,6-diazaanthracene-2,9,10-triones 5a-e, which possess an additional bipyridine substructure, could be isolated as main products.In order to modify the starting products of type 1, a metal-catalyzed cross-coupling reaction with acetylenic benzoic esters 9a,b has been performed.T he modified pyridopyrazines 10a,b which were obtained in good yields could be transformed by analogy to 1a,b into ring-fused heterocyclic quinones 12a,b.