NEW SYNTHESES OF BILIVERDINS, CORROLES AND AZAPORPHYRINS FROM 1,19-DIBROMO-AC-BILADIENE SALTS

Treatment of the readily available, 1.19 dibromo-ac-biladiene dihydrob romide salts 3 with dimethyl sulfoxide (DMSO) in presence of a catalyt ic amount of toluene-p-sulfonic acid affords symmetrical and unsymmetr ical biliverdins 4 in excellent yield; unsymmetrically substituted 1.1 9 dibromo-ac-biladiene dihydrobromide 3c was prepared in a stepwise fa shion via a tripyrrin salt. Under appropriate reaction conditions, the ac-biladiene dihydrobromides were also converted in modest yields int o the corroles 5 and the azaporphyrins 6.