- Determination of the sequential order of acidity in a polyhydroxylated benzophenone series. Consequence on the oxidation reaction in relation to hepatotoxicity
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The pKa values of successive acid-base equilibria involved in the pyrogallol ring ionisation of exifone, 2,3,4-trihydroxybenzophenone 1, and related methoxy derivatives were determined by UV-VIS absorption spectrometry and potentiometric titration.Due to strong intramolecular hydrogen bonding, the sequential order of acidity of the three hydroxy groups of 1 was found to be 4-OH > 3-OH > 2-OH.The polyhydroxylated benzophenones were oxidized to 3,4-quinone only in a narrow range of acidity in which the monoanionic 4-olate species predominated in solution.The attachment of an amino-alcohol residue resulted in the trapping of the transient 3,4-quinone and provided a convenient route to novel 1,4-benzoxazine derivatives.Cytotoxicity experiments in rat hepatocytes indicated that some of these compounds were significantly less toxic than the parent exifone.
- Largeron, Martine,Langevin-Bermond, Dominique,Fleury, Maurice-Bernard
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p. 893 - 900
(2007/10/03)
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- NOVEL 1,4-BENZOXAZINE DERIVATIVES OF PHARMACOLOGICAL INTEREST. ELECTROCHEMICAL AND CHEMICAL SYNTHESES.
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The reaction of electrochemically or chemically generated orthoquinones with aminoalcohols, in methanol, affords a convenient route to novel 1,4-benzoxazine derivatives.Some of these compounds are found to possess interesting pharmacological properties.
- Largeron, Martine,Dupuy, Helene,Fleury, Maurice-Bernard
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p. 4953 - 4968
(2007/10/02)
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