title: Synthesis, spectroscopic, and in vitro photosensitizing efficacy of ketobacteriochlorins derived from ring-B and ring-D reduced chlorins via pinacol-pinacolone rearrangement.
abstract: In this report, we present a regioselective oxidation of a series bacteriochlorins, which on reacting with either ferric chloride (FeCl(3)) or 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) yielded the corresponding ring-B or ring-D reduced chlorins. The effect of the number of electron-withdrawing groups present at the peripheral position, with or without a fused isocyclic ring (ring-E), did not make any significant difference in regioselective oxidation of the pyrrole rings. However, depending on the nature of substituents, the intermediate bis-dihydroxy bacteriochlorins on subjecting to pinacol-pinacolone reaction conditions gave various ketochlorins. The introduction of the keto-group at a particular position in the molecule possibly depends on the stability of the intermediate carbocation species. The newly synthesized bacteriochlorins show strong long-wavelength absorption and produced significant in vitro (Colon26 cells) photosensitizing ability. Among the compounds tested, the bacteriochlorins containing a keto-group at position 7 of ring-B with cleaved five-member isocyclic ring showed the best efficacy.
authors.affiliation: Chemistry Division, PDT Center, Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, United States.
authors.forename: Penny
authors.initials: P
authors.lastname: Joshi
authors.forename: Manivannan
authors.initials: M
authors.lastname: Ethirajan
authors.forename: Lalit N
authors.initials: LN
authors.lastname: Goswami
authors.forename: Avinash
authors.initials: A
authors.lastname: Srivatsan
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Missert
authors.forename: Ravindra K
authors.initials: RK
authors.lastname: Pandey
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D002074:Butanones; D005290:Ferric Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D013057:Spectrum Analysis; D013237:Stereoisomerism
chemical_list: D016227:Benzoquinones; D002074:Butanones; D005290:Ferric Compounds; D017319:Photosensitizing Agents; D011166:Porphyrins; C452433:bacteriochlorin; C000928:dichlorodicyanobenzoquinone; C084935:pinacolone