Benzyl Bromide → Benzyl betulinate

HRID 338622

Reaction equation

HRID 338622 reaction equation
[CH3:1][C:2]([C@H:4]1[C@@H:8]2[C@@H:9]3[C@@:22]([CH3:25])([CH2:23][CH2:24][C@@:7]2([C:31]([OH:33])=[O:32])[CH2:6][CH2:5]1)[C@@:21]1([CH3:26])[C@@H:12]([C@:13]2([CH3:30])[C@@H:18]([CH2:19][CH2:20]1)[C:17]([CH3:28])([CH3:27])[C@@H:16]([OH:29])[CH2:15][CH2:14]2)[CH2:11][CH2:10]3)=[CH2:3].C(=O)([O-])[O-].[K+].[K+].[CH2:40](Br)[C:41]1[CH:46]=[CH:45][CH:44]=[CH:43][CH:42]=1>CN(C=O)C>[OH:29][C@H:16]1[CH2:15][CH2:14][C@@:13]2([CH3:30])[C@@H:18]([CH2:19][CH2:20][C@:21]3([CH3:26])[C@@H:12]2[CH2:11][CH2:10][C@H:9]2[C@@:22]3([CH3:25])[CH2:23][CH2:24][C@@:7]3([C:31]([O:33][CH2:40][C:41]4[CH:46]=[CH:45][CH:44]=[CH:43][CH:42]=4)=[O:32])[CH2:6][CH2:5][C@@H:4]([C:2]([CH3:1])=[CH2:3])[C@@H:8]32)[C:17]1([CH3:27])[CH3:28]

Participants

5

Reactant 3

HCID 7498Benzyl BromideHCID 11430Potassium CarbonateHCID 64971Betulinic Acid

Product 1

HCID 44626706Benzyl betulinateYield 97%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
60 °C

Procedure

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 with 200 mL of water and the solids that formed were collected by filtration to give (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 (13.92 g, 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).

Workup

  1. temperatureit was cooled to rt
  2. customto precipitate
  3. temperatureupon cooling
  4. additionThe mixture was diluted with 200 mL of water
  5. customthe solids that formed
  6. filtrationwere collected by filtration

Sources & evidence

ORD record
ord-68f595aebf2947bcb2a72769fa478412
Source dataset
uspto-grants-2014_11
Patent number
US08889854B2

Linked notes

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