反应详情

1 gr of tabersonine was dissolved in 150 ml of methanol containing 0.0066% (weight/volume) of Rose Bengal as a photosensitizer. 2 ml of NaOH 2 N and 1.5 ml of triethyl phosphite were added and irradiation was provided with a tungsten lamp of 300 W for about 50 minutes, maintaining a constant flow of oxygen equal to 5-10 l/hour and a temperature of 20° C. in the solution. After the reaction was complete, the solution was concentrated to a residue under reduced pressure, taken up with chloroform and filtered on neutral alumina. The solvent was dry evaporated, the residue was taken up with 20 ml of glacial AcOH and 2 gr of AcONa.3H2O, 150 ml of methanol was added and dilution was made to 300 ml with water, then refluxing was conducted for 15 minutes. The solution was cooled, alkalized at pH 8.5-9 with concentrated ammonium hydroxide and extracted with chloroform. The organic extracts were combined, washed with water, dried on sodium sulfate, filtered and concentrated into a residue. The residue was recrystallized from methanol. 600 mgr of Δ14 -vincamine (yield of 57%) and 200 mgr of Δ14 -16-epivincamine (yield of 19%) were obtained. The physico-chemical data of the obtained products were identical to those of corresponding reference compounds.

1. customirradiation
2. customwas provided with a tungsten lamp of 300 W for about 50 minutes
3. customa temperature of 20° C.
4. concentrationthe solution was concentrated to a residue under reduced pressure
5. filtrationfiltered on neutral alumina
6. customThe solvent was dry
7. customevaporated
8. additionwas added
9. temperaturerefluxing
10. temperatureThe solution was cooled
11. extractionextracted with chloroform
12. washwashed with water
13. customdried on sodium sulfate
14. filtrationfiltered
15. concentrationconcentrated into a residue
16. customThe residue was recrystallized from methanol