Formation of N21,N22-Etheno-Bridged Meso-Tetraphenylphlorins

Article abstract of DOI:10.1246/cl.1990.1351

N²¹,N²²-(1,2-Diphenyletheno)-meso-tetraphenylporphin hydroperchlorate was reduced by NaBH4 to the 5H-phlorin and deprotonated by NaOH to the free base.However, the N²¹,N²²-hydroxymethyletheno derivative underwent intramolecular attack of the bridge hydroxy group on the 10-meso position to give the novel 10H-phlorin under basic conditions.