Tetrabutylammonium Fluoride → (1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-1-isopropenyl-9-(4-methoxycarbonylphenyl)-5a,5b,8,8,11a-pentamethyl-1,2,3,4,5,6,7,7a,11,11b,12,13,13a,13b-tetradecahydrocyclopenta[a]chrysene-3a-carboxylic acid

HRID 338626Notes

Reaction equation

HRID 338626 reaction equation
[CH3:1][O:2][C:3]([C:5]1[CH:10]=[CH:9][C:8]([C:11]2[C:12]([CH3:49])([CH3:48])[C@H:13]3[C@:26]([CH3:29])([CH2:27][CH:28]=2)[C@@H:25]2[C@:16]([CH3:47])([C@@:17]4([CH3:46])[C@H:22]([CH2:23][CH2:24]2)[C@H:21]2[C@H:30]([C:33]([CH3:35])=[CH2:34])[CH2:31][CH2:32][C@:20]2([C:36]([O:38][Si](C(C)(C)C)(C)C)=[O:37])[CH2:19][CH2:18]4)[CH2:15][CH2:14]3)=[CH:7][CH:6]=1)=[O:4].CCCC[N+](CCCC)(CCCC)CCCC.[F-]>O1CCOCC1.Cl.O>[CH3:1][O:2][C:3]([C:5]1[CH:10]=[CH:9][C:8]([C:11]2[C:12]([CH3:49])([CH3:48])[C@H:13]3[C@:26]([CH3:29])([CH2:27][CH:28]=2)[C@@H:25]2[C@:16]([CH3:47])([C@@:17]4([CH3:46])[C@H:22]([CH2:23][CH2:24]2)[C@H:21]2[C@H:30]([C:33]([CH3:35])=[CH2:34])[CH2:31][CH2:32][C@:20]2([C:36]([OH:38])=[O:37])[CH2:19][CH2:18]4)[CH2:15][CH2:14]3)=[CH:7][CH:6]=1)=[O:4]

Participants

6

Reactant 2

HCID 2724141Tetrabutylammonium FluorideHCID 67776655(1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-tert-butyldimethylsilyl 9-(4-(methoxycarbonyl)phenyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylate

Product 1

HCID 54759950(1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-1-isopropenyl-9-(4-methoxycarbonylphenyl)-5a,5b,8,8,11a-pentamethyl-1,2,3,4,5,6,7,7a,11,11b,12,13,13a,13b-tetradecahydrocyclopenta[a]chrysene-3a-carboxylic acidYield 99.2%

Reagents, catalysts & solvents 3

HCID 313Hydrochloric AcidSolventHCID 962WaterSolventHCID 312751,4-DioxaneSolvent

Procedure

To solution of (1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-tert-butyldimethylsilyl 9-(4-(methoxycarbonyl)phenyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylate (3.12 g, 4.54 mmol) in dioxane (25 mL) was added TBAF (75% wt in water) (2.375 g, 6.81 mmol). The mixture was stirred at rt for 4 h then was diluted with 1N HCl (25 mL) and water (5 mL) and extracted with dichloromethane (3×100 mL). The combined organic layers were dried with Na2SO4, filtered, and partially concentrated under reduced pressure to about 10 mL in volume. To the partially concentrated mixture was added 1N HCl (50 mL). The solids that formed were collected by filtration and were washed with water. The expected product, (1R,3aS,5aR,5bR,7aR,11aS,11bR,13 aR,13bR)-9-(4-(methoxycarbonyl)phenyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylic acid (2.58 g, 99% yield), was isolated as a white solid. LCMS: m/e 571.47 (M−H)−, 3.60 min (method 1). 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 9.80 (br. s., 1H), 7.92 (d, J=8.24 Hz, 2H), 7.18 (d, J=8.24 Hz, 2H), 5.32-5.26 (m, 1H), 4.75 (s, 1H), 4.62 (br. s., 1H), 3.90 (s, 3H), 3.07-2.99 (m, 1H), 2.33-2.21 (m, 2H), 2.10 (dd, J=17.09, 6.10 Hz, 1H), 2.06-1.94 (m, 2H), 1.70 (s, 3H), 1.01 (br. s., 3H), 1.00 (br. s., 3H), 0.98 (s, 3H), 0.91 (s, 6H), 1.79-0.89 (m, 17H).

Workup

  1. extractionextracted with dichloromethane (3×100 mL)
  2. dry with materialThe combined organic layers were dried with Na2SO4
  3. filtrationfiltered
  4. concentrationpartially concentrated under reduced pressure to about 10 mL in volume
  5. additionTo the partially concentrated mixture was added 1N HCl (50 mL)
  6. customThe solids that formed
  7. filtrationwere collected by filtration
  8. washwere washed with water

Sources & evidence

ORD record
ord-6d7415d3c71b4c08848197821cffd216
Source dataset
uspto-grants-2014_11
Patent number
US08889854B2

Reaction notes

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