title: Porphyrins bearing stable meso-alkylidenyl double bonds. A new family of nonplanar porphyrinoids.
abstract: [Structure: see text] Unique core-modified porphyrinoids, such as oxabenziporphyrins, oxapyriporphyrins, and thiapyriporphyrins, bearing exocyclic C-C double bonds at meso-positions, have been synthesized and characterized. The synthesis was accomplished by utilizing typical "3+1"-type condensation. Two different stable tautomeric forms were isolated, and the two tautomeric forms can be interconvertible upon treatment with base. In contrast, only the structure bearing an exocyclic double bond was isolated in the case of oxapyriporphyrin and oxabenziporphyrin.
authors.affiliation: Department of Chemistry, Kangwon National University, Chun-Chon 200-701, Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Sim
authors.forename: Seung-Doo
authors.initials: SD
authors.lastname: Jeong
authors.forename: Dae-Wi
authors.initials: DW
authors.lastname: Yoon
authors.forename: Seong-Jin
authors.initials: SJ
authors.lastname: Hong
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Kang
authors.forename: Chang-Hee
authors.initials: CH
authors.lastname: Lee