47122-74-7

Upstream product

• 517-30-6 (+) eburnamenine 
• 690993-33-0 (3R,16R)-14,15-dihydroeburnamenin-19-one 
• 442632-27-1 (3R)-3-ethyldihydro-3-(2-propenyl)-2(3H)-furanone 
• 442632-29-3 (3R)-3-ethyltetrahydro-2-methoxy-3-(2-propenyl)furan 
• 442632-25-9 (3R)-3-ethyldihydro-5-hydroxy-3-(2-propenyl)-2(3H)-furanone 
• 442632-31-7 3-((R)-3-Ethyl-2-methoxy-tetrahydro-furan-3-yl)-propan-1-ol 
• 442632-33-9 3-((R)-3-Ethyl-2-methoxy-tetrahydro-furan-3-yl)-propionic acid 
• 81075-90-3 (2R)-2,3-dideoxy-2-ethyl-2-(2-propenyl)-D-glyceropentanoic acid γ-lactone 
• 443777-76-2 (1R,12bR)-1-ethyl-2,3,6,7,12,12b-hexahydro-1-(2-hydroxyethyl)-indolo[2,3-a]quinolizin-4(1H)-one 
• 690993-30-7 (1R,12bR)-1-ethyl-2,3,6,7,12,12b-hexahydro-1-[2-[(methanesulfonyl)oxy]ethyl]indolo[2,3-a]quinolizin-4(1H)-one 
• 690993-29-4 (1R,12bR)-1-ethyl-2,3,6,7,12,12b-hexahydro-1-(2-acetoxyethyl)-indolo[2,3-a]quinolizin-4(1H)-one 
• 517-30-6 (+/-)-3-epieburnamenine 
• 173738-67-5 3-ethyl-3-(2-indol-1-ylethyl)piperidin-2-one 
• 173738-68-6 3-Ethyl-3-(2-indol-1-yl-ethyl)-piperidine-2-thione 

Relevant academic research and scientific papers

Total syntheses of (-)-vallesamidine and related Aspidosperma and Hunteria type indole alkaloids from the common intermediate

A new synthetic method of (-)-vallesamidine, including a unique 2,2,3-trialkylindoline skeleton, was developed by reductive radical cyclization reaction from the 2,3-dialkylindole derivative, which has been known to be an intermediate for the synthesis of

Cycloaddition Reaction of Mesoionic Betaines as an Approach toward Trialkylindoline Alkaloids

Intramolecular 1,4-dipolar cycloaddition of an anhydro-4-hydroxy-2-oxo-1,3-thiazium hydroxide across a tethered indole π-bond has been used for the construction of the pentacyclic skeleton of epi-16,17-dihydroeburnamenine. The reaction of 3-ethyl-3-(alkenyl)piperidinones with diketene and trimethylsilyl triflate in benzene at ambient temperature produced annulated pyridones in good yield. The initial reaction involved formation of a N-acetoacetylated amide which was further converted to the pyridone with TMSOTf. The overall process was found to proceed with complete stereospecificity. Treating a sample of 3-ethyl-3-[(E)-4-phenyl-3-butenyl]-2-piperidone with diketene and TMSOTf produced a cycloadduct in 63% yield whose stereochemistry was elucidated by a X-ray crystallographic study. The epimeric Z-isomer produced a different stereoisomer of the annulated dihydropyridone. The mechanism of the annulation involves a TMSOTf induced cyclization followed by proton removal and generation of a cross-conjugated heteroaromatic betaine. This 1,4-dipole undergoes a subsequent intramolecular dipolar cycloaddition across the neighboring π-bond, and the resulting cycloadduct is subsequently converted to the annulated lactam. A related annulation sequence leading to a key intermediate previously utilized in the synthesis of the (±)-vallesamidine has been developed which is based on the intramolecular dipolar cycloaddition of a mesoionic betaine intermediate.

An expedient synthesis of epi-eburnamenine via an intramolecular 1,4-dipolar cycloaddition reaction

The intramolecular 1,4-dipolar cycloaddition of an anhydro-4-hydroxy-2-oxo-1,3-thiazium hydroxide across a tethered indole π-bond has been used for the construction of the pentacyclic skeleton of epi-16,17-dihydroeburnamenine.

Synthetic Approach to (+/-)- Vincamine via Cleavage of an α-Diketone Monothioacetal. Alternative Synthesis of (+/-)-Eburnamine, (+/-)-Isoeburnamine, and (+/-)-Eburnamenine

The half ester (8) prepared from cleavage of 2-(1,3-dithian-2-yl)-4-ethoxycarbonyl-4-ethylcyclohexanone (7) has been converted into (+/-)-eburnamine (20), (+/-)-isoeburnamine (21), and (+/-)-eburnamenine (22) by a stereospecific reaction sequence proceeding via the dithian intermediate (16).However an attempted conversion of (16) into (+/-)-vincamine (6) was unsuccessful.