On the syntheses of 1,3‐disubstituted dithieno[3,4‐ b :3′,2′‐ d ]pyridines via halogen‐metal exchange of 1,3‐dibromodithieno[3,4‐ b :3′,2′‐ d ]pyridine

Halogen‐metal exchange of 1,3‐dibromodithieno[3,4‐ b :3′,2′‐ d ]pyridine with butyllithium under different conditions has been studied. Upon reaction with iodine, N,N ‐dimethylacetamide, N,N ‐dimethylformamide, dimethyl carbonate, dimethyl disulfide and thiuram disulfide, the 1,3‐diiodo‐, 1,3‐diacetyl‐, 1,3‐diformyl‐, 1,3‐dicarbomethoxy, 1,3‐di(thiomethyl)‐ and 1,3‐di( N,N ‐dimethyldithiocarbamoyl)dithieno[3,4‐ b :3′,2′‐ d ]‐pyridines, respectively, were obtained in varying yields. 3‐Monosubstituted derivatives were obtained in some cases. The formation of 3,7‐disubstituted derivatives was sometimes also observed.