31248-76-7

Upstream product

• 3851-29-4 2,3-(R,R)-11b-(S)-(3-ethyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-α]isoquinoline-2-yl)acetic acid methyl ester 
• 20776-45-8 5-benzyloxytryptamine 
• 21197-07-9 2,3-(R,R)-11b-(S)-N-[2-(5-benzyloxy-1H-indol-3-yl)-ethyl]-2-(3-ethyl-9,10-dimethoxy-1,3,4,6,7,7a,11a,11b-octahydro-2H-pyrido[2,1-α]isoquinolin-2-yl)acetamide 

Downstream Products

• 2632-29-3 Tubulosine 
• 30833-25-1 O-benzyltubulosine 

Relevant academic research and scientific papers

Enantioselective total syntheses of the Ipecacuanha alkaloid emetine, the Alangium alkaloid tubulosine and a novel benzoqainolizidine alkaloid by using a domino process

The first enantioselective syntheses of the Ipecacuanha alkaloid emetine (1) and the Alangium alkaloid tubulosine (2) is described employing a domino Knoevenagel/hetero-Diels-Alder reaction and an enantioselective catalytic transfer hydrogenation of imines as key steps. Thus, hydrogenation of the imine 15 with the catalyst (R,R)-16 gives the tetrahydroisoquinoline 14 with 95% ee which was transformed into the aldehyde (1S)-7. The three-component domino reaction of (1S)-7 with 6 and 8 led to 19, which in a second domino process was treated with K2CO3 in methanol followed by a hydrogenation to give the benzoquinolizidine 4 together with the diastereomers 22 and 23 in a overall yield of 66%. Further transformation of 4 with the amines 3 and 5 yielded enantiopure emetine (1) and tubulosine (2), respectively. In addition, starting from 19 the novel benzoquinolizidine alkaloid 34 was synthesised; this compound resembles the vallesiachotamine alkaloid dihydroantirhin 31, which has not been isolated so far but probably must also exist in nature.