Synthesis of pyridopyrazine-1,6-diones from 6-hydroxypicolinic acids via a one-pot coupling/cyclization reaction.

A facile one-pot synthesis of 3,4-dihydro-1H-pyrido[1,2-a]pyrazine-1,6(2H)-diones (pyridopyrazine-1,6-diones) has been developed which employs a sequential coupling/cyclization reaction of 6-hydroxypicolinic acids and β-hydroxylamines. The transformation proceeds in good yield under mild conditions using O-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU) to both carry out the amide formation and activate the hydroxyl group for intramolecular alkylation.