Benzyl Bromide → Benzyl betulinate

HRID 406862

Reaction equation

HRID 406862 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 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, 25.5 mmol, 97% yield) as a white solid. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 0.74 (s, 3H), 0.75 (s, 3H), 0.79 (s, 3H), 0.82-1.71 (m, 20H), 0.93 (s, 3H), 0.95 (s, 3H), 1.67 (s, 3H), 1.81-1.93 (m, 2H), 2.13-2.21 (m, 1H), 2.27 (ddd, J=12.36, 3.20, 3.05 Hz, 1H), 3.01 (td, J=10.99, 4.88 Hz, 1H), 3.17 (ddd, J=11.44, 5.65, 5.49 Hz, 1H), 4.59 (s, 1H), 4.71 (d, J=1.83 Hz, 1H), 5.06-5.16 (m, 2H), 7.28-7.39 (m, 5H).

Workup

  1. temperaturewas 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-b836702e3c784f52b6d1dde715ce9750
Source dataset
uspto-grants-2014_06
Patent number
US08754068B2

Linked notes

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