Effective synthesis of 3,5-diaryl-(1H)-pyrazin-2-ones via microwave mediated ring closure

In this study we report on a flexible straight forward synthesis toward novel 3,5-diaryl-(1H)-pyrazin-2-ones. Our synthetic strategy involved an acyclic di-keto derivative as key intermediate. The final pyrazin-2-one ring closure reaction was yield-optimized by using a microwave mediated procedure and ammoniumacetate as nitrogen source. Our method is a suitable alternative to palladium-catalyzed coupling reactions for the 3,5-diaryl decoration of the (1H)-pyrazin-2-one scaffold. Since the (1H)-pyrazin-2-ones is present as scaffold in a number of biologically active compounds the reported synthetic platform is a useful approach to generate a set of highly diverse 3,5-diaryl-(1H)-pyrazin-2-one compounds. (C) 2013 Elsevier Ltd. All rights reserved.