Facile Synthesis of 3‐Substituted‐1,2,3,4‐tetrahydropyrido‐[3,2‐ d ]pyrimidine‐2,4‐dione on Poly(ethylene glycol)

An efficient and short route to synthesize pyrido[3,2‐ d ]pyrimidinediones was achieved using poly(ethylene glycol) as a soluble polymeric support and phase transfer catalyst. The poly(ethylene glycol) (PEG) was reacted with 2,3‐pyridinedicarboxylic anhydride to give PEG‐bound ester 1 , which was transformed into corresponding PEG‐bound acyl azide 2 . Then the PEG‐supported acyl azide 2 was rearranged, reacted with a series of amines and spontaneously cycled to give product 5 in 84%–88% overall yields.