Title:
置換ポルフィリン
Document Type and Number:
Japanese Patent JP2006501163
Kind Code:
A
Abstract:
A series of ortho isomers of meso tetrakis N-alkylpyridylporphyrins (alkyl being methyl, ethyl, n-propyl, n-butyl, n-hexyl, and n-octyl) and their Mn(III) complexes were synthesized and characterized by elemental analysis, uv/vis spectroscopy, electrospray ionization mass spectrometry and electrochemistry. An increase in the number of carbon atoms in the alkyl chains from 1 to 8 is accompanied by an increase in: (a) lipophilicity measured by the chromatographic retention factor, Rf; (b) metal-entered redox potential, E1/2 from +220 to +367 mV vs NHE, and (c) proton dissociation constant, pKa2 from 10.9 to 13.2. A linear correlation was found between E1/2 and Rf of the Mn(III) porphyrins and between the pKa2 and Rf of the metal-free compounds. As the porphyrins become increasingly more lipophilic, the decrease in hydration disfavors the separation of charges, while enhancing the electron-withdrawing effect of the positively charged pyridyl nitrogen atoms. Consequently, the E1/2 increases linearly with the increase in pKa2, a trend in porphyrin basicity opposite from the one we previously reported for other water-soluble Mn(III) porphyrins. All of these Mn(III) porphyrins are potent catalysts for superoxide dismutation (disproportionation). Despite the favorable increase of E1/2 with the increase in chain length, the catalytic rate constant decreases from methyl (log kcat=7.79) to n-butyl, and then increases such that the n-octyl is as potent an SOD mimic as are the methyl and ethyl compounds. The observed behavior originates from an interplay of hydration and steric effects that modulate electronic effects.
Inventors:
Batinik-Habare, Ines
Spa Sojevic, Ivan
Fridovich, Irwin
Spa Sojevic, Ivan
Fridovich, Irwin
Application Number:
JP2004510799A
Publication Date:
January 12, 2006
Filing Date:
June 09, 2003
Export Citation:
Assignee:
Duke University
International Classes:
C07D487/22; A61K31/409; A61P11/06; A61P39/06; C07F13/00
Domestic Patent References:
| JPH11221964A | 1999-08-17 | |||
| JP2001521939A | 2001-11-13 |
Attorney, Agent or Firm:
Takehiko Suzue
Satoshi Kono
Makoto Nakamura
Kurata Masatoshi
Yoshihiro Fukuhara
Sadao Muramatsu
Ryo Hashimoto
Satoshi Kono
Makoto Nakamura
Kurata Masatoshi
Yoshihiro Fukuhara
Sadao Muramatsu
Ryo Hashimoto