Reaktion #582307

Reaktionsgleichung

D-alanine

triethylamine

ethyl trifluoroacetate

→

N-(trifluoroacetyl)-D-alanine

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONis added
2. 2
   workup.STIRRINGto homogenise the mixture (approx. 1 day)
3. 3
   EinengenThe solution is concentrated on a rotavapor (35° C.; 16 mmHg)
4. 4
   workup.DISSOLUTIONdissolved in the mixture THF/water (1:1; 140 ml)
5. 5
   workup.ADDITIONAcidic ion exchanger Dowex 50W-X8 (100 g) is added
6. 6
   workup.STIRRINGstirred for 10 minutes
7. 7
   Filtrationfiltered
8. 8
   Einengenconcentrated again on a rotavapor (35° C.; 16 mmHg)
9. 9
   Sonstige(80° C.; 0.05 mmHg)
10. 10
    SonstigeThe pure product in the form of colourless crystals is obtained (33.50 g; 80.8%)

Vorschrift

To the mixture of D-alanine (20.00 g; 0.224 mol) and triethylamine (31.3 ml; 0.224 mol) in absolute methanol (100 ml), ethyl trifluoroacetate (33.4 ml; 0.280 mol) is added and stirred at room temperature to homogenise the mixture (approx. 1 day). The solution is concentrated on a rotavapor (35° C.; 16 mmHg) and then dissolved in the mixture THF/water (1:1; 140 ml). Acidic ion exchanger Dowex 50W-X8 (100 g) is added, stirred for 10 minutes, filtered and concentrated again on a rotavapor (35° C.; 16 mmHg). The residue is sublimed (80° C.; 0.05 mmHg). The pure product in the form of colourless crystals is obtained (33.50 g; 80.8%).

Quelle