Ammonium Acetate → Benzyl (2r, 4r)-4-acetoxy-2-(4,5-diphenyloxazol-2-yl)pyrrolidine-1-carboxylate

HRID 431756Notes

Reaction equation

O=[C:2]([C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1)[CH:3]([O:10][C:11](=O)[C@H:12]1[CH2:16][C@@H:15](O)[CH2:14][N:13]1[C:18]([O:20][CH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1)=[O:19])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[C:35]([O-:38])([CH3:37])=[O:36].[NH4+:39]>CC(O)=O>[C:35]([O:38][C@H:15]1[CH2:14][N:13]([C:18]([O:20][CH2:21][C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=2)=[O:19])[C@@H:12]([C:11]2[O:10][C:3]([C:4]3[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=3)=[C:2]([C:29]3[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=3)[N:39]=2)[CH2:16]1)(=[O:36])[CH3:37]

Participants

Conditions

Temperature: 120 °C

Procedure

A mixture of cis-4-hydroxy-N-benzyloxycarbonyl-D-proline 2-oxo-1,2-diphenylethyl ester (7.0 g) and AcONH4 (11.8 g) in AcOH was stirred at 120° C. for 1 hour. The reaction mixture was evaporated, and the residue was dissolved in EtOAc, washed with water, 3N NaOH solution, water and brine, dried (MgSO4), and evaporated in vacuo. The residue was purified by silica gal column chromatography (hexane-EtOAc, 1:1˜2:3 elution) to give first benzyl (2R, 4R)-4-acetoxy-2-(4,5-diphenyloxazol-2-yl)pyrrolidine-1-carboxylate (972.6 mg), then benzyl (2R, 4R)-2-(4,5-diphenyloxazol-2-yl)-4-hydroxypyrrolidine-1-carboxylate (5.12 g).

Workup

customThe reaction mixture was evaporated
dissolutionthe residue was dissolved in EtOAc
washwashed with water, 3N NaOH solution, water and brine
dry with materialdried (MgSO4)
customevaporated in vacuo
customThe residue was purified by silica gal column chromatography (hexane-EtOAc, 1:1˜2:3 elution)

Sources & evidence

ORD record: ord-23d763cce1f14dd8b622e044c2936670
Source dataset: uspto-grants-2003_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06660759B1

Reaction notes

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