Nv. Chizhova et al., Bromination of tetraazaporphine and its beta-substituted derivatives usingpyridine as solvent and catalyst, RUSS J G CH, 71(4), 2001, pp. 567-569
The selectivity and degree of bromination of pyrrole rings in porphyrazine
strongly depends on the brominating agent and solvent nature. The reaction
of porphyrazine magnesium complex with molecular bromine and N-bromosuccini
mide in pyridine gave magnesium complex of dibromotetraazaporphine. Increas
ing bromine substitution in porphyrazine enhances its acidic properties.