Pyrido[2,3-b]pyrazines from Pyrazine C-Nucleosides: An Unusual Intramolecular Rearrangement

摘要

Our synthesis of pyrazihe C-nucleosides has involved the use of a palladium-mediated coupling method which provides 3'-keto pyrazine nucleosides as key intermediates. We have found that some of these 3'-keto pyrazine nucleosides Undergo an unusual rearrangement to form pyrido[2,3-b]pyrazine compounds. We believe that this rearrangement coujd be a general route to form various other heterocycles via the appropriate 3'-keto nucleosides.