title: Production of bacteriopurpurin-18 phytyl ester from bacteriopheophytin a via allomerization by contact with titanium oxides in the presence of molecular oxygen.
abstract: Incubation of bacteriopheophytin (BPhe) a, which was a demetalated pigment of bacteriochlorophyll a in photosynthetic bacteria, in CH2Cl2 in the presence of TiO2 particles with bubbling O2 in the dark produced a pigment absorbing 814nm. Detailed characterization of the novel pigment isolated from the CH2Cl2 suspension revealed that bacteriopurpurin-18 phytyl ester possessing an anhydride-type six-membered exocyclic E-ring was majorly formed by the treatment with TiO2 particles under oxygenic conditions. Oxidation of the bacteriochlorin ring in BPhe a, namely formations of derivatives of 3-acetyl pheophytin a and 3-acetyl protopheophytin a, can barely be detected through the conversion processes.
authors.affiliation: Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan. Electronic address: saga@chem.kindai.ac.jp.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Saga
authors.affiliation: Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ishitani
authors.affiliation: Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawamura
mesh_terms: D002384:Catalysis; D004952:Esters; D008752:Methylene Chloride / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010674:Pheophytins / Q000737:chemistry*; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry*
chemical_list: D004952:Esters; D010674:Pheophytins; D011166:Porphyrins; C009495:titanium dioxide; C006678:bacteriopheophytin; D008752:Methylene Chloride; D014025:Titanium; D010100:Oxygen
keywords: Allomerization; Bacteriochlorophyll; Bacteriopheophytin; Near-infrared; Titanium oxide