Chemical Transformations Of Some Kniphofia Quinones

Chemical investigation of the rhizome of Kniphofia fotiosa (Hochst),rnAsphodelaceae, led to the isolation of a minor product code named KKA-1 (40) . Thernspectral data suggested that it was a dimer of knipholone (32) and its anthrone (33) . Thisrnwas further confirmed by reductive cleavage to 4,6- dihydroxy-2- methoxyacetophenonern(37), acetylphlorogtucinol (36) , and chrysophanol (5) . It was synthesized fromrnknipholone anthrone (33) through oxidative coupling reactions.rnThe synthesis of 4,6-dihydroxy-2- methoxyacetophenone (37), a consitiuent of AT.rnfotiosa, is reported. Knipholone (32) was synthesized from knipholone anthrone ( 33)rnthrough oxidation. Reductive cleavage of knipholone (32) gave chrysophanol (5), 4,6-rndihydroxy-2- methoxyacetophenone (37 ) and acetylphloroglucinol (36) . Bromination ofrnknipholone anthrone (33) resulted in four bromides: 41, 42, 43 and 45 . These bromidesrnwere not stable in solution

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