Synthesis of porphyrins with ABAB symmetry from dipyrromethanes as potential phototherapeutic agents

BOARINI, MILENA B.; PÉREZ, MARÍA EUGENIA; MILANESIO, MARIA ELISA; DURANTINI, EDGARDO NÉSTOR

Conferencia; The 24th International Electronic Conference on Synthetic Organic Chemistry, Session: Bioorganic, Medicinal and Natural Products Chemistry; 2020

Asymmetrically meso-substituted porphyrins were synthesized with ABAB symmetry patterns. The approach required the formation of dipyrromethanes, which were obtained from the condensation of an aldehyde (pentafluorobenzaldehyde, 4-nitrobenzaldehyde or N,N-diphenylaminobenzaldehyde) with a large excess of pyrrole (1:47 aldehyde/pyrrole mol ratio), catalyzed by trifluoroacetic acid in 70-94% yields. Then, acid catalyzed condensation of these dipyrromethanes with an aldehyde (N,N-dimethylaminobenzaldehyde, 4-carboxymethyl benzaldehyde or N-ethyl-3-carbazolecarbaldehyde) (1:1 mol ratio) in dichloromethane, followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone affords the diseased porphyrins in 10-42% yields. These ABAB-porphyrins are interesting starting materials to obtain photoactive molecular structures as potential phototherapeutic agents.