Ethyl 2-formylcyclopropanecarboxylate → methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-(ethoxycarbonyl)cyclopropyl)methylamino)-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 85646

Reaction equation

HRID 85646 reaction equation
[NH2:1][C@:2]12[CH2:37][CH2:36][C@@H:35]([C:38]([CH3:40])=[CH2:39])[C@@H:3]1[C@@H:4]1[C@@:17]([CH3:20])([CH2:18][CH2:19]2)[C@@:16]2([CH3:21])[C@@H:7]([C@:8]3([CH3:34])[C@@H:13]([CH2:14][CH2:15]2)[C:12]([CH3:23])([CH3:22])[C:11]([C:24]2[CH:33]=[CH:32][C:27]([C:28]([O:30][CH3:31])=[O:29])=[CH:26][CH:25]=2)=[CH:10][CH2:9]3)[CH2:6][CH2:5]1.[CH:41]([CH:43]1[CH2:45][CH:44]1[C:46]([O:48][CH2:49][CH3:50])=[O:47])=O.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>ClCCCl.CC(C)[O-].[Ti+4].CC(C)[O-].CC(C)[O-].CC(C)[O-]>[CH2:49]([O:48][C:46]([CH:44]1[CH2:45][CH:43]1[CH2:41][NH:1][C@:2]12[CH2:37][CH2:36][C@@H:35]([C:38]([CH3:40])=[CH2:39])[C@@H:3]1[C@@H:4]1[C@@:17]([CH3:20])([CH2:18][CH2:19]2)[C@@:16]2([CH3:21])[C@@H:7]([C@:8]3([CH3:34])[C@@H:13]([CH2:14][CH2:15]2)[C:12]([CH3:22])([CH3:23])[C:11]([C:24]2[CH:25]=[CH:26][C:27]([C:28]([O:30][CH3:31])=[O:29])=[CH:32][CH:33]=2)=[CH:10][CH2:9]3)[CH2:6][CH2:5]1)=[O:47])[CH3:50]

Participants

6

Reactant 3

HCID 89334Ethyl 2-formylcyclopropanecarboxylate2×HCID 5049666Sodium triacetoxyborohydride2×HCID 68357865methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-amino-1-isopropenyl-5a,5b,8,8,11a-pentamethyl-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

Product 1

HCID 68358206methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-(ethoxycarbonyl)cyclopropyl)methylamino)-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 89.1%

Reagents, catalysts & solvents 2

HCID 11026Titanium isopropoxideCatalystHCID 111,2-DichloroethaneSolvent

Procedure

To a solution of methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-amino-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 (30 mg, 0.055 mmol) in DCE (0.5 mL) was added ethyl 2-formyl-1-cyclopropanecarboxylate (9.13 mL, 0.069 mmol) and titanium(IV) isopropoxide (0.020 mL, 0.069 mmol). The mixture was stirred at rt for 1 h and sodium triacetoxyborohydride (23.38 mg, 0.110 mmol) was added. After stirring the mixture for 16.25 h additional ethyl 2-formyl-1-cyclopropanecarboxylate (9.13 mL, 0.069 mmol) and sodium triacetoxyborohydride (23.38 mg, 0.110 mmol) were added and the mixture was again stirred at rt for 24 h. The reaction mixture was loaded directly onto a silica gel column and was purified by flash chromatography using a 0-25% EtOAc in hexanes gradient. The fractions containing the expected product were combined and concentrated under reduced pressure to give methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-(ethoxycarbonyl)cyclopropyl)methylamino)-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 (33 mg, 0.049 mmol, 89% yield). LCMS: m/e 670.8 (M+H)+, 2.47 min (method 11).

Workup

  1. additionwere added
  2. stirringthe mixture was again stirred at rt for 24 h
  3. customwas purified by flash chromatography
  4. additionThe fractions containing the expected product
  5. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-276430780282461cbcf0073f1dc6eb1f
Source dataset
uspto-grants-2014_09
Patent number
US08846647B2

Linked notes

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