Réaction #1435689

Équation de réaction

2-bromopropionic acid chloride

β-alanine-benzyl ester-p-toluenesulfonic acid salt

triethylamine

hydrochloric acid

→

2-Bromopropionyl-β-alanine-benzyl ester

Solvants

water

methylene chloride

Conditions de réaction

Traitement

1. 1
   Autreto exceed 5° C
2. 2
   workup.ADDITIONAfter addition
3. 3
   workup.WAITfor 2 hours at room temperature
4. 4
   AutreThe organic phase is separated
5. 5
   Lavagewashed once each with 300 ml of 5% aqueous hydrochloric acid, 300 ml of 5% aqueous soda solution and 400 ml of water
6. 6
   AutreThe organic phase is dried on magnesium sulfate
7. 7
   Autreevaporated to dryness in a vacuum
8. 8
   AutreThe residue recrystallizes from diisopropyl ether

Mode opératoire

53.65 g (313 mmol) of 2-bromopropionic acid chloride is added in drops at 0° C. to 100 g (285 mmol) of β-alanine-benzyl ester-p-toluenesulfonic acid salt and 31.67 g (313 mmol) of triethylamine in 400 ml of methylene chloride. The temperature is not allowed to exceed 5° C. After addition is completed, it is stirred for 1 hour at 0° C., then for 2 hours at room temperature. 500 ml of ice water is added, and the water phase is set at pH 2 with 10% aqueous hydrochloric acid. The organic phase is separated, washed once each with 300 ml of 5% aqueous hydrochloric acid, 300 ml of 5% aqueous soda solution and 400 ml of water. The organic phase is dried on magnesium sulfate and evaporated to dryness in a vacuum. The residue recrystallizes from diisopropyl ether.

Source