Trifluoroacetic acid → Allobetulin

HRID 840767Notes

Reaction equation

HRID 840767 reaction equation
FC(F)(F)C(O)=O.[CH3:8][C:9]([C@H:11]1[C@@H:15]2[C@@H:16]3[C@@:29]([CH3:32])([CH2:30][CH2:31][C@@:14]2([CH2:38][OH:39])[CH2:13][CH2:12]1)[C@@:28]1([CH3:33])[C@@H:19]([C@:20]2([CH3:37])[C@@H:25]([CH2:26][CH2:27]1)[C:24]([CH3:35])([CH3:34])[C@@H:23]([OH:36])[CH2:22][CH2:21]2)[CH2:18][CH2:17]3)=[CH2:10]>ClCCl>[CH3:32][C@:29]12[C@:28]3([CH3:33])[CH2:27][CH2:26][C@H:25]4[C:24]([CH3:34])([CH3:35])[C@@H:23]([OH:36])[CH2:22][CH2:21][C@:20]4([CH3:37])[C@H:19]3[CH2:18][CH2:17][C@@H:16]1[C@@H:15]1[C@@:14]3([CH2:38][O:39][C@H:11]1[C:9]([CH3:8])([CH3:10])[CH2:12][CH2:13]3)[CH2:31][CH2:30]2

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 72326Betulin

Product 1

HCID 11080733Allobetulin

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Trifluoroacetic acid (5 ml, 99%) was added to betulin (2 g) in 50 ml of dichloromethane at 0° C. The resulting solution was stirred for 30 minutes, poured into 100 ml of cracked ice, extracted with CH2Cl2 (3×10 ml), washed with concentrated NaHCO3 (2×20 ml) and water (2×20 ml), and dried over anhydrous Na2SO4. Evaporation of the solvent gave allobetulin, which was recrystallized from hexane-dichloromethane to yield white needles (yield 1.98 g, mp 268-269° C. [lit. 265-268° C.]); IR (KBr) 3448.5, 2941.5, 2866.6, 1780.7, 1456.6, 1384.4, 1168.9, 1035.0, cm−1; 1H NMR (CDCl3) δ 3.75 (D, J=10.3 Hz, 1H, 28-H), 3.51 (S, 1H, 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, 25H); 13C NMR (CDCl3) δ 88.41, 79.38, 71.49, 55.77, 51.35, 47.07, 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.

Workup

  1. extractionextracted with CH2Cl2 (3×10 ml)
  2. washwashed with concentrated NaHCO3 (2×20 ml) and water (2×20 ml)
  3. dry with materialdried over anhydrous Na2SO4
  4. customEvaporation of the solvent

Sources & evidence

ORD record
ord-616b5b7dddfa4dd3b44062a9808f3839
Source dataset
uspto-grants-2002_04
Patent number
US06369101B1

Reaction notes

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