Chemical Transformations of Some Kniphofia Quinones
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Date
1994-06
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Addis Ababa Universty
Abstract
Chemical investigation of the rhizome of Kniphofia fotiosa (Hochst),
Asphodelaceae, led to the isolation of a minor product code named KKA-1 (40) . The
spectral data suggested that it was a dimer of knipholone (32) and its anthrone (33) . This
was further confirmed by reductive cleavage to 4,6- dihydroxy-2- methoxyacetophenone
(37), acetylphlorogtucinol (36) , and chrysophanol (5) . It was synthesized from
knipholone anthrone (33) through oxidative coupling reactions.
The synthesis of 4,6-dihydroxy-2- methoxyacetophenone (37), a consitiuent of AT.
fotiosa, is reported. Knipholone (32) was synthesized from knipholone anthrone ( 33)
through oxidation. Reductive cleavage of knipholone (32) gave chrysophanol (5), 4,6-
dihydroxy-2- methoxyacetophenone (37 ) and acetylphloroglucinol (36) . Bromination of
knipholone anthrone (33) resulted in four bromides: 41, 42, 43 and 45 . These bromides
were not stable in solution
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Keywords
Kniphofia Quinones