Pyrido[2,3-H]-2,6-naphthyridines. I. Synthesis and thermal reactions of the 2,2′bisacylazide of 3,3′ bipyridine

2 The2′-bisacylazide of 3,3′-bipyridine (1) has been synthesized from the (4,7)-phenantholine-5,6-dione ( 3 ) and the thermal decomposition of this new bisacylazide has been shown to give rise to the Curtius rearrangement and subsequent cyclization to the pyrido2,3-h]-2,6-naph-thridinone ring system 8 .