(R)-2-tert-butoxycarbonylamino-3-hydroxy propionic acid → (R)-3-(tert-Butoxy)-2-((tert-butoxycarbonyl)amino)propanoic acid

HRID 2297997Notes

Reaction equation

[C:1]([NH:8][C@@H:9]([C:12]([OH:14])=[O:13])[CH2:10][OH:11])([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2].C(NC(=NC(C)C)O[C:21]([CH3:24])([CH3:23])[CH3:22])(C)C>C(Cl)Cl>[C:21]([O:11][CH2:10][C@H:9]([C:12]([OH:14])=[O:13])[NH:8][C:1]([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2])([CH3:24])([CH3:23])[CH3:22]

Participants

Conditions

Temperature: 0 °C

Procedure

To an ice-cooled solution of N-BOC-D-serine (10 g, 48.7 mmol) in methylene chloride (50 ml) was added N,N′-diisopropyl-O-tert-butylisourea (35 ml, 3.5 M) via addition funnel, over 30 min. The reaction mixture was maintained at 0° C. for 2 hrs and then warmed to room temperature over night. The material was again cooled to 0° C. and a second portion of N,N′-diisopropyl-O-tert-butylisourea (28 ml, 3.5 M) was added. The material was stirred for 2 hrs at 0° C. and then warmed again to room temperature over night. Purification by flash silica gel chromatography using (20%) ethyl acetate/hexanes as eluant gave O-tert-butyl-N-BOC-D-serine (7.97 g) as a viscous oil which solidified on standing.

Workup

additionvia addition funnel
temperaturewarmed to room temperature over night
temperatureThe material was again cooled to 0° C.
temperaturewarmed again to room temperature over night
customPurification by flash silica gel chromatography

Sources & evidence

ORD record: ord-b373e9cdcee347f8b216b154d288057d
Source dataset: uspto-grants-2002_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06492394B1

Reaction notes

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