Trifluoroacetic acid → Allobetulin

HRID 478138Notes

Reaction equation

HRID 478138 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([CH2:31][OH: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)(C(F)(F)F)=O>C(Cl)Cl>[CH3:25][C@:22]12[C@:21]3([CH3:26])[CH2:20][CH2:19][C@H:18]4[C:17]([CH3:27])([CH3:28])[C@@H:16]([OH:29])[CH2:15][CH2:14][C@:13]4([CH3:30])[C@H:12]3[CH2:11][CH2:10][C@@H:9]1[C@@H:8]1[C@@:7]3([CH2:31][O:32][C@H:4]1[C:2]([CH3:1])([CH3:3])[CH2:5][CH2:6]3)[CH2:24][CH2:23]2

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 72326Betulin

Product 1

HCID 11080733AllobetulinYield 99%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

In 100-ml flask stir 2 g of Betulin in 50 ml of CH2Cl2 at 0° C. Add 5 ml of 99% CF3COOH and stir for 30 minutes. Pour, reaction mixture in 100 ml of cracked ice and separate the organic part. Extract with CH2Cl2 (3×10 ml) and wash combined organic extracts with conc. NaHCO3 (2×20 ml) and water (2×20 ml), and dry the extract over Na2SO4 (anh.). Evaporation of solvent gives 1.98 g of Allobetulin, which was recrystallized from hexane-dichloromethane to yield white needles mp. 268-269° C. [lit. 265-268], IR (KBr) 3448.5, 2941.5, 2866.6, 1780.7, 1456.6, 1384.4, 1168.9, 1035.0, cm−1; 1H NMR (CDCl3) d 3.75 (D, J=10.3 Hz, 1H, 28-H), 3.51 (S, 1-H, 19-H), 3.41 (D, J=10.3 Hz, 1H, 28-H), 3.18 (DD, 1H, 3-H), 0.74, 0.76, 0.81, 0.88, 0.89, 0.94, 0.94 (all S, 7×3H, 27-, 23-, 24-, 25-, 26-, 29-, 30-Me), 1.01-1.74 (complex CH—, CH2, 25 H,); 13C NMR (CDCl3) d 88.41, 79.38, 71.49, 55.77, 51.35, 47.07, 41.78, 40.99, 40.88, 40.87, 39.16, 37.52, 36.95, 36.51, 34.40, 34.18, 32.96, 29.08, 28.27, 27.57, 26.72, 26.72, 26.50, 24.82, 21.26, 18.54, 16.79, 15.96, 15.72, 13.82; MS (EI) 442, 424, 411, 371, 355, 303, 273, 257, 245, 231, 220, 207, 203, 189, 177, 162, 149, 135, 121, 107.

Workup

  1. additionPour
  2. customseparate the organic part
  3. extractionExtract with CH2Cl2 (3×10 ml)
  4. washwash
  5. customdry the
  6. extractionextract over Na2SO4 (anh.)
  7. customEvaporation of solvent

Sources & evidence

ORD record
ord-c4032845c6d6437e880e4928e8e25379
Source dataset
uspto-grants-2003_11
Patent number
US06642217B2

Reaction notes

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