Nitration of dithieno[3,2-b:3′,2′-d]pyridine and dithieno[3,2-b:3′,4′-d]pyridine

Nitration of dithieno[3,2-b:3′,2′-d]pyridine ( 4 ) and dithieno[3,2-b:3′,4′-d]pyridine ( 5 ) has been studied. Nitration of 4 occurred in both positions of the C ring, while 5 was predominantly substituted on the 3,4-fused ring. The structures of the nitro derivatives were proven by extensive use of ¹H and ¹³C nmr spectroscopy.