Pyrroles and related compounds. Part XIV. The structure and transformations of oxophlorins (oxyporphyrins)

Abstract

Blue oxophlorins are relatively strong bases and accept one proton (on nitrogen) to form green monocations; addition of a second proton (to the oxo-group) occurs in strongly acidic media to afford the dications derived from the tautomeric hydroxyporphyrins. Oxophlorins also form metal complexes derived from the hydroxy-porphyrin structure, and these compounds are fairly strong acids. Several alkyl and acyl derivatives of the hydroxyporphyrin structure are described. The ferrichloride complex of one oxophlorin has been degraded to glaucobilin-IX β- dimethyl ester through the pure verdohaemin.