tert-butyl N-(2-oxoethyl)carbamate → methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(2-(tert-butoxycarbonylamino)ethylamino)-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 85619Notes

Reaction equation

HRID 85619 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.O=[CH:42][CH2:43][NH:44][C:45](=[O:51])[O:46][C:47]([CH3:50])([CH3:49])[CH3:48].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>ClCCCl.C(O[Ti](OC(C)C)(OC(C)C)OC(C)C)(C)C>[C:47]([O:46][C:45]([NH:44][CH2:43][CH2:42][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:51])([CH3:50])([CH3:49])[CH3:48]

Participants

6

Reactant 3

HCID 4247255tert-butyl N-(2-oxoethyl)carbamateHCID 5049666Sodium triacetoxyborohydrideHCID 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 86676586methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(2-(tert-butoxycarbonylamino)ethylamino)-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

Reagents, catalysts & solvents 2

HCID 178460666HCID 178460666, compoundCatalystHCID 111,2-DichloroethaneSolvent

Procedure

To 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 (1.00 g, 1.84 mmol) in DCE (5 mL) was added tert-butyl 2-oxoethylcarbamate (1.17 g, 7.36 mmol) and tetraisopropoxytitanium (0.700 mL, 2.39 mmol). The reaction mixture was stirred for 1 h, then sodium triacetoxyborohydride (1.17 g, 5.52 mmol) was added. The reaction mixture was stirred for 18 h. The reaction mixture was quenched with sodium bicarbonate and was extracted with DCM (3×40 mL). The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel chromatography using ethyl acetate and hexanes (20-100%) as the eluent to provide the title compound as a pale yellow oil. (900 mg, 71%). LCMS: m/e 688.24 (M+H)+, 2.51 min (method 11).

Workup

  1. stirringThe reaction mixture was stirred for 18 h
  2. customThe reaction mixture was quenched with sodium bicarbonate
  3. extractionwas extracted with DCM (3×40 mL)
  4. dry with materialThe combined organic layers were dried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated under reduced pressure
  7. customThe residue was purified by silica gel chromatography

Sources & evidence

ORD record
ord-806435adcb7e4815b2cb855cad8850b0
Source dataset
uspto-grants-2014_09
Patent number
US08846647B2

Reaction notes

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