Nitration of 2,5-dimethylthiophene with copper(II) nitrate in acetic anhydride gives 2,5-dimethyl-3-nitrothiophene and 3,2′-methylene (2,5-dimethylthiophene) (5′-methylthiophene) as major products. Treatment of 3,4-dibromo-2,5-dimethylthiophene with nitricacid (d = 1.5) in dichloromethane in the presence of a catalytic amount of sulfuric acid yields 3,4-dibromo-5-methyl-2-nitrooxymethylthiophene as