Reaktion #78918

Reaktionsgleichung

Mercaptoacetic acid

(L)-leucine methyl ester

triethylamine

p-chlorobenzaldehyde

→

4-Methyl-2-(S)-[2-(RS)-(4-chlorophenyl)-4-oxo-thiazolidin-3-yl]-pentanoic Acid Methyl Ester

Lösungsmittel

dioxane

ethyl acetate

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITION3 Å molecular sieves were added
2. 2
   TemperaturThe mixture was heated at 80° C. for 4 hrs
3. 3
   workup.WAITthe heating was continued for an additional 12 hrs
4. 4
   TemperaturThe reaction mixture was cooled to room temperature
5. 5
   FiltrationThe reaction mixture was filtered
6. 6
   Sonstigeto remove the molecular sieves
7. 7
   workup.ADDITIONThe organic layer was diluted with ethyl acetate (100 ml)
8. 8
   Waschenwashed twice with 60 ml of saturated solution of sodium carbonate, twice with aqueous 1N HCl and once with water
9. 9
   TrocknenThe organic layer was dried with MgSO4
10. 10
    Sonstigeevaporated
11. 11
    Sonstigeto give a residue that
12. 12
    Sonstigewas carried out to the next step without further purification

Vorschrift

A suspension of (L)-leucine methyl ester (10 g, 55 mmol) and triethylamine (7.7 ml, 55 mmol) in 120 ml of dioxane was stirred at room temperature for 5 minutes. 3 Å molecular sieves were added followed by p-chlorobenzaldehyde (17 g, 121 mmol). The mixture was heated at 80° C. for 4 hrs. Mercaptoacetic acid (14.2 ml, 203.5 mmol) was added to the mixture and the heating was continued for an additional 12 hrs. The reaction mixture was cooled to room temperature, and diluted with ethyl acetate (40 ml) and water (30 ml). The reaction mixture was filtered to remove the molecular sieves. The organic layer was diluted with ethyl acetate (100 ml), washed twice with 60 ml of saturated solution of sodium carbonate, twice with aqueous 1N HCl and once with water. The organic layer was dried with MgSO4 and evaporated to give a residue that was carried out to the next step without further purification.

Quelle