The scheme described for structural proof established that monobrominated 3-methyl-4- carbethoxypyrrole is predominantly 2-bromo-3-methyl-4-carbethoxypyrrole. This is indicated by the fact that iodination leads to a bromoiodopyrrole which is identical with the 2-bromo-3- methyl-4-carbethoxy-5-iodopyrrole obtained from 2-bromo-3-methyl-4-carbethoxy-d- carbomethoxypyrrole. The isomeric bromoiodopyrrole, 2-iodo-3-methyl-4-carbethoxy-5- ...
