Reaktion #48400

Reaktionsgleichung

HCl

benzyl N2,N2-bis(tert-butoxycarbonyl)-5-(2,3-dichlorophenyl)-D-lysinate

NaOH

triethylamine

NaHCO3

EDC

HOAT

→

di-tert-butyl [(3R)-6-(2,3-dichlorophenyl)-2-oxoazepan-3-yl]imidodicarbonate

Ausbeute 82.3%

Lösungsmittel

MeOH

water

DCM

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenconcentrated
2. 2
   Sonstigethe layers separated
3. 3
   TrocknenThe combined organics were dried over magnesium sulfate
4. 4
   Filtrationfiltered
5. 5
   Einengenconcentrated
6. 6
   SonstigeThis residue was purified by silica gel chromatography (0.5%→10% MeOH/DCM)

Vorschrift

To a solution benzyl N2,N2-bis(tert-butoxycarbonyl)-5-(2,3-dichlorophenyl)-D-lysinate (0.45 g, 0.77 mmol) in MeOH (4 mL) and water (2 mL) was added 1N NaOH (3.1 mL, 3.1 mmol). This solution was heated to 40° C. for 6 h, then neutralized with 1N HCl and concentrated. To a solution of this residue in DCM (10 mL) were added EDC (0.19 g, 0.97 mmol) and HOAT (53 mg, 0.39 mmol) followed by triethylamine (0.32 mL, 0.73 mmol). After 2 h, NaHCO3 was added, the layers separated and the aqueous phase backwashed with DCM. The combined organics were dried over magnesium sulfate, filtered and concentrated. This residue was purified by silica gel chromatography (0.5%→10% MeOH/DCM) to give di-tert-butyl [(3R)-6-(2,3-dichlorophenyl)-2-oxoazepan-3-yl]imidodicarbonate (300 mg). MS 473 (M+1). Standard deprotection of a portion of this material gave the title product. MS 273 (M+1).

Quelle