Reaktion #77312

Reaktionsgleichung

(R)-4-carbobenzyloxypiperazine-2-carboxylic acid

1,2-dichloro-fluoro-5-nitrobenzene

water

dimethylformamide

→

title compound

Ausbeute 157.3%

(R)-8,9-Dichloro-2,3,4,4a-Tetrahydro-1H-Pyrazino[1,2-a]Quinoxalin-5(6H)-One

Ausbeute 157.3%

Lösungsmittel

triethylamine

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeat ambient temperature
2. 2
   Sonstigeovernight
3. 3
   EinengenThe dark orange solution is concentrated under reduced pressure (1-2 mm, <50° C.) to an orange oily residue
4. 4
   workup.DISSOLUTIONThis oil is dissolved in 400 mL of ethyl acetate
5. 5
   Waschenwashed with 100 mL of 1 N HCl (2×), with 150 mL of water (2×), and 100 mL of brine
6. 6
   TrocknenThe organic layer is dried over MgSO4
7. 7
   Filtrationfiltered
8. 8
   Einengenconcentrated

Vorschrift

To a slurry containing 5.0 g of (R)-4-carbobenzyloxypiperazine-2-carboxylic acid, 4.2 g of 1,2-dichloro-fluoro-5-nitrobenzene, 85 mL of water and 170 mL of dimethylformamide is added slowly 5.3 mL of triethylamine. The solution is heated to 50° C. for 5 hours, then at ambient temperature overnight. The dark orange solution is concentrated under reduced pressure (1-2 mm, <50° C.) to an orange oily residue. This oil is dissolved in 400 mL of ethyl acetate and washed with 100 mL of 1 N HCl (2×), with 150 mL of water (2×), and 100 mL of brine. The organic layer is dried over MgSO4, filtered and concentrated to give 8.1 g (94.2%) of title compound as an orange solid foam.

Quelle