Benzyl Bromide → Benzyl betulinate

HRID 85547Notes

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

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 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).

Workup

temperatureit was cooled to rt
customto precipitate
temperatureupon cooling
customthe solids that formed
filtrationwere collected by filtration

Sources & evidence

ORD record: ord-8b80b1428ebb418897ce4b40a1e944d8
Source dataset: uspto-grants-2014_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08846647B2

Reaction notes

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