Reaktion #172729

Reaktionsgleichung

betulinic acid

potassium carbonate

benzyl bromide

→

title compound

Ausbeute 97.0%

(1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-benzyl 9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxylate

Ausbeute 97.0%

Lösungsmittel

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturit was cooled to rt
2. 2
   Sonstigeto precipitate
3. 3
   Temperaturupon cooling
4. 4
   Sonstigethe solids that formed
5. 5
   Filtrationwere collected by filtration

Vorschrift

To a suspension of betulinic acid (12 g, 26.3 mmol) and potassium carbonate (7.26 g, 52.6 mmol) in DMF (150 mL) was added benzyl bromide (3.28 mL, 27.6 mmol). The mixture was heated to 60° C. for 3.5 h, and then it was cooled to rt. Solids started to precipitate upon cooling. The mixture was diluted water (200 mL) and the solids that formed were collected by filtration to give the title compound (13.92 g, 25.5 mmol, 97% yield) as a white solid. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 7.39-7.28 (m, 5H), 5.16-5.06 (m, 2H), 4.71 (d, J=1.83 Hz, 1H), 4.59 (s, 1H), 3.17 (ddd, J=11.44, 5.65, 5.49 Hz, 1H), 3.01 (td, J=10.99, 4.88 Hz, 1H), 2.27 (ddd, J=12.36, 3.20, 3.05 Hz, 1H), 2.21-2.13 (m, 1H), 1.93-1.81 (m, 2H), 1.67 (s, 3H), 0.95 (s, 3H), 0.93 (s, 3H), 1.71-0.82 (m, 20H), 0.79 (s, 3H), 0.75 (s, 3H), 0.74 (s, 3H).

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