Transition metal-catalyzed orthogonal solid-phase decoration of the 2(1H)-pyrazinone scaffold using a sulfur linker.

A new transition metal-catalyzed orthogonal solid-phase protocol for the synthesis of highly substituted 2(1H)-pyrazinones was developed, on the basis of Chan-Lam arylation and Liebeskind-Srogl cross-coupling reactions. This strategy opens the way for the generation of small libraries of 2(1H)-pyrazinone analogues for biological screening.

The application of "click chemistry" for the decoration of 2(1H)-pyrazinone scaffold: generation of templates.

The "click chemistry" approach has been explored on the 2-(1H)-pyrazinone scaffold for the generation of pharmacologically interesting heterocyclic moieties. Huisgen 1,3-dipolar cycloaddition has been evaluated as the key step for the construction of the 1,2,3-triazole ring at the C-3 position of 2-(1H)-pyrazinones. Two different pathways have been successfully evaluated: (1) via C-C or C-O linkage of the acetylenic part to the C-3 position of the 2-(1H)-pyrazinone scaffold or (2) via azide introduction in the C-3 position.

Solid-phase synthesis of the 2(1H)-pyrazinone scaffold: a new approach toward diversely substituted heterocycles.

The first solid-phase synthesis of the 2(1H)-pyrazinone scaffold is described. The diversity at position C6 of the pyrazinone ring is determined by the choice of the starting aldehyde. Microwave-enhanced transition metal-catalyzed reactions allow easy introduction of a variety of substituents at the C3 position.

Microwave-enhanced transition metal-catalyzed decoration of 2(1H)-pyrazinone scaffolds.

The 2(1H)-pyrazinones have been demonstrated to be versatile building blocks for the synthesis of biologically active compounds. Here, an efficient method is described for the decoration of these interesting scaffolds. Microwave-assisted palladium catalyzed reactions allow the easy introduction of different substituents at the C3- and even at the rather unreactive C5-position of the pyrazinones.

The effect of pressure on microwave-enhanced Diels-Alder reactions. A case study.

It is demonstrated that microwave-assisted Diels-Alder reactions of substituted 2(1H)-pyrazinones with ethylene are significantly more effective utilizing pre-pressurized (up to 10 bar) reaction vessels.