Acetic Anhydride → 10376-50-8

HRID 2179762Notes

Reaction equation

HRID 2179762 reaction equation
[CH3:1][C:2](OC(C)=O)=[O:3].[OH:8][C@H:9]1[CH2:26][CH2:25][C@@:24]2([CH3:27])[C@@H:11]([CH2:12][CH2:13][C@:14]3([CH3:38])[C@@H:23]2[CH2:22][CH2:21][C@H:20]2[C@@:15]3([CH3:37])[CH2:16][CH2:17][C@@:18]3([C:34]([OH:36])=[O:35])[CH2:30][CH2:29][C@@H:28]([C:31]([CH3:33])=[CH2:32])[C@@H:19]32)[C:10]1([CH3:40])[CH3:39]>CN(C1C=CN=CC=1)C.N1C=CC=CC=1>[C:2]([O:8][C@H:9]1[CH2:26][CH2:25][C@@:24]2([CH3:27])[C@@H:11]([CH2:12][CH2:13][C@:14]3([CH3:38])[C@@H:23]2[CH2:22][CH2:21][C@H:20]2[C@@:15]3([CH3:37])[CH2:16][CH2:17][C@@:18]3([C:34]([OH:36])=[O:35])[CH2:30][CH2:29][C@@H:28]([C:31]([CH3:33])=[CH2:32])[C@@H:19]32)[C:10]1([CH3:40])[CH3:39])(=[O:3])[CH3:1]

Participants

5

Reactant 2

HCID 7918Acetic AnhydrideHCID 64971Betulinic Acid

Product 1

HCID 1030053410376-50-8Yield 59.8%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 1049PyridineSolvent

Procedure

Ac2O (about 0.93 ml, 9.87 mmol) was added to a stirred solution of (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxylic acid (Betulinic acid, about 0.3 g, 0.657 mmol) and DMAP (about 0.167 g, 1.32 mmol) in pyridine (about 15 ml) at about 0° C. then the reaction mixture was slowly warmed to room temperature and refluxed for about 24 hours. After completion of the reaction (monitored by TLC), the reaction mixture poured in to ice water and extracted with EtOAc and washed with water, brine and dried over Na2SO4, the solvent was evaporated and purified by silica gel column (100-200, elution 10% EtOAc in hexane) to afford title compound as a off white solid. Wt: 0.196 g; Yield: 59.8%; 1H NMR (300 MHZ, CDCl3): δ 4.74 (s, 1H), 4.61 (s, 1H), 4.50-4.44 (m, 1H), 3.02-2.97 (m, 1H), 3.01-2.12 (m, 2H), 2.04 (s, 3H), 1.99-1.92 (m, 2H), 1.69 (s, 3H), 1.68-1.57 (m, 6H), 1.56-1.32 (m, 10H), 1.31-1.01 (m, 5H), 0.97, 0.93 (2s, 6H), 0.85 (Brs, 9H); Mass: [M−1] 497 (100%); IR (KBr, cm−1): 3296, 2945, 1736, 1694, 1464, 1368, 1247, 1196, 1161, 1024, 980, 884, 777, 543; M.R: 283.7° C.-290.1° C.; HPLC: 97.17%.

Workup

  1. temperaturerefluxed for about 24 hours
  2. customAfter completion of the reaction (monitored by TLC)
  3. extractionextracted with EtOAc
  4. washwashed with water, brine
  5. dry with materialdried over Na2SO4
  6. customthe solvent was evaporated
  7. custompurified by silica gel column (100-200, elution 10% EtOAc in hexane)

Sources & evidence

ORD record
ord-a72523d67939480e888cda1eafbe3fb3
Source dataset
uspto-grants-2015_06
Patent number
US09067966B2

Reaction notes

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