methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(hydroxymethyl)-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]chrysen-9-yl)benzoate → methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-formyl-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]chrysen-9-yl)benzoate

HRID 405090Notes

Reaction equation

HRID 405090 reaction equation
[OH:1][CH2:2][C@:3]12[CH2:38][CH2:37][C@@H:36]([C:39]([CH3:41])=[CH2:40])[C@@H:4]1[C@@H:5]1[C@@:18]([CH3:21])([CH2:19][CH2:20]2)[C@@:17]2([CH3:22])[C@@H:8]([C@:9]3([CH3:35])[C@@H:14]([CH2:15][CH2:16]2)[C:13]([CH3:24])([CH3:23])[C:12]([C:25]2[CH:34]=[CH:33][C:28]([C:29]([O:31][CH3:32])=[O:30])=[CH:27][CH:26]=2)=[CH:11][CH2:10]3)[CH2:7][CH2:6]1.C1C=C[NH+]=CC=1.[O-][Cr](Cl)(=O)=O>C(Cl)Cl>[CH:2]([C@:3]12[CH2:38][CH2:37][C@@H:36]([C:39]([CH3:41])=[CH2:40])[C@@H:4]1[C@@H:5]1[C@@:18]([CH3:21])([CH2:19][CH2:20]2)[C@@:17]2([CH3:22])[C@@H:8]([C@:9]3([CH3:35])[C@@H:14]([CH2:15][CH2:16]2)[C:13]([CH3:24])([CH3:23])[C:12]([C:25]2[CH:26]=[CH:27][C:28]([C:29]([O:31][CH3:32])=[O:30])=[CH:33][CH:34]=2)=[CH:11][CH2:10]3)[CH2:7][CH2:6]1)=[O:1]

Participants

4

Reactant 2

HCID 54759951methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(hydroxymethyl)-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]chrysen-9-yl)benzoateHCID 178418287HCID 178418287, compound

Product 1

HCID 86676415methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-formyl-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]chrysen-9-yl)benzoateYield 80.3%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(hydroxymethyl)-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]chrysen-9-yl)benzoate (1 g, 1.789 mmol) in CH2Cl2 (70 ml) was added PCC (1.157 g, 5.37 mmol). The resulting dark brown mixture was stirred at rt for 4 h. TLC analysis showed the reaction was complete. The mixture was filtered through a short bed of Celite and silica gel, washed with excess of CH2Cl2. The filtrate was concentrated in vacuo. The crude mixture was purified by Biotage on normal phase silica gel. The fractions containing the expected product were combined and concentrated in vacuo to afford methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-formyl-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]chrysen-9-yl)benzoate as a solid (0.8 g). LCMS: m/e 557.2 (MH+), 3.67 min (method 2).

Workup

  1. filtrationThe mixture was filtered through a short bed of Celite and silica gel
  2. washwashed with excess of CH2Cl2
  3. concentrationThe filtrate was concentrated in vacuo
  4. customThe crude mixture was purified by Biotage on normal phase silica gel
  5. additionThe fractions containing the expected product
  6. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-f8277a31cb514a849403f1145f20dcf6
Source dataset
uspto-grants-2014_06
Patent number
US08748415B2

Reaction notes

Loading…