Trimethylsilylacetylene → 2-Bromo-5-trimethylsilanylethynyl-pyrazine

Participants

Reaction Steps

Reaction of a mixture of 2-bromo-5-iodo-pyrazine and copper (1) iodide under inert conditions in an appropriate solvent and base e.g. DMF/Et3N with ethynyl-trimethyl-silane using a palladium catalyst e.g. Pd(PPh3)4 at room temperature gives 2-Bromo-5-trimethylsilanylethynyl-pyrazine. This material can be used without further purification and reacted to form 6-bromo-2-trimethylsilanyl-pyrazolo[1,5-a]pyrazine using O-(mesitylenesulfonyl)hydroxylamine to form the N-amino adduct. This can then be cyclised by reacting with base e.g. K2CO3 to form pyrazolopyrazine core (Scheme 6).

Provenance & Evidence