32790-10-6

Upstream product

• 112817-47-7 (5aR,10aS,11R,12aR,12bS)-5a-Amino-12a-ethyl-11-hydroxy-4,5,5a,10,11,12,12a,12b-octahydro-3H-3a,10-diaza-indeno[1,7-ma]fluorene-11-carboxylic acid methyl ester 
• 4429-63-4 tabersonine 

Downstream Products

• 6835-99-0 14-epivincamine 

Relevant academic research and scientific papers

Synthesis of vinca alakaloids and realated compounds 98 [1]. Oxidation with dimethyldioxirane of compounds containing the aspidospermane and quebrachamine ring system. A simple synthesis of (7s,20S)-(+)-rhazidigenine and (2R,7S,20S)-(+)-rhazidine

The oxidation of (-)-tabersonine (1) with dimethyldioxirane (DMD) in neutral and acidic medium gave 16-hydroxytabersonine-N-oxide (3) and the didehydrovincamine isomers 4 and 5, respectively. (+)-14,15-Didehydro-quebrachamine (7) furnished the hydroxyindolenine 9, and the pentacyclic derivative 11. (+)- Quebrachamine (8) and DMD in neutral medium gave (7S,20S)-(+)-rhazidigenine (12) which was converted to (2R,7S,20S)-(+)-rhazidine (13b) with hydrochloric acid.

Oxidation of β-Anilinoacrylate Alkaloids Vincadifformine and Tabersonine by Fremy's Salt. A Mechanistic Insight into the Rearrangement of Aspidosperma to Hunteria Alkaloids

β-Anilinoacrylate Aspidosperma alkaloids vincadifformine (2a) and tabersonine (2b) react with Fremy's salt in aqueous acidic conditions via radical coupling at C-16.The resulting zwitterionic compounds 7a and 10 rearange to isoxazolidines 8 and then ultimately to azepinoindoles 9.The mechanism of these reactions is discussed, and the structures of 7a, 8b, and 9a were established by single-crystal X-ray analysis.Diazotization of amine 20b (X = NH2) affords fragmentation-cyclization products corresponding to eburnanes 18 and 21.This reaction mimics the skeletal rearrangement of Aspidosperma -> Hunteria alkaloids, and these findings support Wenkert's biogenetic proposal.

Dye-sensitized Photo-oxygenation of the Aspidosperma Alkaloids Vincadifformine and Tabersonine. A New, Convenient Approach to Vincamine

The dye-sensitized photo-oxygenation of (-)-vincadifformine (1) and (-)-tabersonine (3) is discribed.Reaction takes place through the intermediate formation of 16-hydroperoxyindolenines, which decompose to give 2,16-seco-products or which can be efficently trapped by reductants to give a new stereoselective synthesis of the 16-hydroxy-indoles (10) and (14).These compounds are the key precursors to the eburnane alcaloids vincamine (4) and Δ14-vincamine (6).Suitable experimental conditions give compounds (4) and (6) in good yields directly from their Aspidosperma precursor.

Ozonation in Alkaloid Chemistry: a Mild and Selective Conversion of Vincadifformine into Vincamine

Vincamine has been obtained in a 'one-pot' method by ozonation of vincadifformine.

AROMATIC SUBSTITUTION EFFECTS IN THE ASPIDOSPERMANE-EBURNANE REARRANGEMENT OF INDOLE ALKALOIDS

The influence of substitutions in aromatic part of indole alkaloids with aspidosperma skeleton on their rearrangement into products with eburnane-type structure is studied.Results are applied to vincamine derivatives.