N-[4-methoxybenzenesulfonyl]-(D)-valine → N-[(4-methoxyphenyl)sulfonyl]-D-valine tert-butyl ester
Reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([S:9]([NH:12][C@H:13]([CH:17]([CH3:19])[CH3:18])[C:14]([OH:16])=[O:15])(=[O:11])=[O:10])=[CH:5][CH:4]=1.C(NC(=NC(C)C)O[C:26]([CH3:29])([CH3:28])[CH3:27])(C)C>C(Cl)Cl>[C:26]([O:15][C:14](=[O:16])[C@H:13]([NH:12][S:9]([C:6]1[CH:7]=[CH:8][C:3]([O:2][CH3:1])=[CH:4][CH:5]=1)(=[O:11])=[O:10])[CH:17]([CH3:19])[CH3:18])([CH3:29])([CH3:28])[CH3:27]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
To an ice-cooled solution of 2(R)-(4-methoxybenzenesulfonylamino)-3-methylbutyric acid (7.0 g, 21.25 mmol) in dry methylene chloride was added N,N′-diisopropyl-O-tert-butylisourea (12.1 mL, 3.5M) via addition funnel over 45 min. The reaction mixture was maintained at 0° C. for 2 h and then allowed to warm to room temperature overnight. The reaction mixture was loaded onto a flash silica gel column and eluted with ethyl acetate/hexane (5%) to give 2(R)-(4-methoxybenzenesulfonylamino)-3-methylbutyric acid tert-butyl ester (7.02 g) as a white crystalline solid.
Workup
- additionvia addition funnel over 45 min
- temperatureto warm to room temperature overnight
- washeluted with ethyl acetate/hexane (5%)
Sources & evidence
- ORD record
- ord-7b2fdcb09426402bb4a95428e907bfbe
- Source dataset
- uspto-grants-2005_01
- Patent number
- US06844366B2
Reaction notes
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