212-38-4Relevant academic research and scientific papers
OCCURRENCE OF TWO EPIMERIC ALKALOIDS AND METABOLISM COMPARED WITH LYCORINE IN CRINUM LATIFOLIUM
Ghosal, Shibnath,Unnikrishnan, Sankara,Singh, Sushil K.
, p. 2535 - 2537 (1989)
Two new epimeric pyrrolophenanthridine alkaloids, 2-epilyocorine and 2-epipancrassidine, were isolated from the flower-stem fluid of Crinum latifolium.The structures of the two alkaloids were established by spectroscopic analyses, crucial chemical transformation, and synthesis in case of the former.The differences in the metabolic pathways of lycorine and 2-epilycorine were studied under simulated physiological conditions and their biochemical significance was appraised.Key Word Index - Crinum latifolium; Amaryllidaceae; epimeric alkaloids; 2-epilycorine; 2-epipancrassidine, metabolic pathways; biochemical significance.
Total synthesis of (±)-α-lycorane and 4,5-dehydroanhydrolycorine
Rigby, James H.,Mateo, Mary E.
, p. 10569 - 10582 (2007/10/03)
The total syntheses of (±)-α-lycorane and dehydroanhydrolycorine are described. The key intermediate in both approaches is the hydroindolone 5, prepared from the [1 + 4] cycloaddition reaction of 1-isocyanatocyclohexene and cyclohexyl isocyanide. Alkylation of 5 with arylbromide 6 afforded 7. Hydrolysis of enamide 7 followed by reduction of the resultant enol yielded 10 as a single diastereomer. Radical-based cyclization of this intermediate gave 11 possessing the requisite trans-fusion between rings B and C in good yield. Radical deoxygenation followed by reduction of the amide carbonyl function afforded (±)-α-lycorane. Similarly, alkylation of 5 with 6-(chloromethyl)-5-iodo-1,3-benzodioxole gave 14. Treatment of 14 with Pd(OAc)2 employing the Jeffery modification of the Heck reaction gave tetracycle 9. Hydrolysis of 9 followed by oxidation with DDQ afforded 15. Reduction of the two carbonyl functions in this material using lithium aluminum hydride afforded 4-hydroxyanhydrolycorine (16). Mesylation of the hydroxyl group led to rapid, spontaneous elimination producing anhydrodehydrolycorine.
