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

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