Synthesis of halogenoazoles

Reassignment of the structures of iodonitroimidazole, its N-methyl derivatives, and related compounds

“…Pauly found that sodium sulfite reduction of diiodoimidazole gave an iodoimidazole 17, bromination of which gave a dibromoiodoimidazole (18) which was not identical with the compound (21) obtained by iodination of 2,4dibromoimidazole (20), whose structure was defined by virtue of its mode of synthesis17 from 4(5)-(carboethoxy)imidazole (19). Pauly therefore argued that the iodo substituent in iodoimidazole is in the 2-position and that diiodoimidazole has structure 14. On reexamining this reaction sequence, we found that the bromination of iodoimidazole in chloroform solution gives a strongly acidic compound which requires 1 equiv of sodium hydroxide for neutralization.…”