Reaktion #1620

Reaktionsgleichung

potassium carbonate

diethyl dibromomalonate

(R)-2-(3,4-dihydroxyphenyl)propylcarbamic acid, t-butyl ester

→

(R)-5-[N-(t-Butyloxycarbonyl)-2-aminopropyl]-1,3-benzodioxole-2,2-dicarboxylic acid, diethyl ester

Lösungsmittel

acetone

acetone

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter cooling to ambient temperature
2. 2
   workup.STIRRINGthe reaction was stirred at ambient temperature for 18 hours
3. 3
   FiltrationThe suspension was filtered
4. 4
   Waschenthe residue was washed with ethyl acetate
5. 5
   Sonstigeevaporated
6. 6
   Sonstigethe residue was partitioned between ethyl acetate (200 ml) and dilute hydrochloric acid (100 ml, pH5)
7. 7
   SonstigeThe organic layer was separated
8. 8
   Waschenwashed with water (2×100 ml) and brine (100 ml)
9. 9
   Trocknendried (MgSO4)
10. 10
    Sonstigeevaporated
11. 11
    SonstigeThe residue was purified by column chromatography on silica gel eluting with 25% ethyl acetate in n-hexane giving the title compound as an oil

Vorschrift

A solution of (R)-2-(3,4-dihydroxyphenyl)propylcarbamic acid, t-butyl ester. (1.07 g, 4 mMol) in acetone (25 ml) containing potassium carbonate (3 equiv, 1.66 g, 12 mMol) was stirred at 60° C. under an argon atmosphere for 1 hour. After cooling to ambient temperature, a solution of diethyl dibromomalonate (1.27 g, 4 mMol) in acetone (7 ml) was added and the reaction was stirred at ambient temperature for 18 hours. The suspension was filtered and the residue was washed with ethyl acetate. The filtrates were combined, evaporated and the residue was partitioned between ethyl acetate (200 ml) and dilute hydrochloric acid (100 ml, pH5). The organic layer was separated, washed with water (2×100 ml) and brine (100 ml), dried (MgSO4) and evaporated. The residue was purified by column chromatography on silica gel eluting with 25% ethyl acetate in n-hexane giving the title compound as an oil;

Quelle