Reaction #1121773

Reaction equation

diethyl ether

3-benzyl-2-aminopyrazine

2-Amino-3-benzylpyrazine

pyridine

tetrabutylamoniumtribromide

→

title compound 13

Yield 89.0%

2-Amino-3-benzyl-5-bromopyrazine

Yield 89.0%

Solvents

chloroform

Conditions

Workup

1. 1
   WashAfter 1 h the reaction mixture was washed with 20% aqueous solution of NaCl
2. 2
   Dryingthe organic layer was then dried over Na2SO4
3. 3
   Filtrationfiltered
4. 4
   Otherthe solvent removed under reduced pressure
5. 5
   OtherThe crude was purified by flash chromatography (EtOAc-dichloromethane, 80:20)
6. 6
   Otherto get

Procedure

To a solution of 3-benzyl-2-aminopyrazine 12 (1.38 g, 7.40 mmol) in chloroform (40 mL), pyridine (1.80 mL, 22.00 mmol) and tetrabutylamoniumtribromide TBATB (3.57 g, 7.40 mmol) were added at room temperature. After 1 h the reaction mixture was washed with 20% aqueous solution of NaCl, the organic layer was then dried over Na2SO4, filtered and the solvent removed under reduced pressure. The crude was purified by flash chromatography (EtOAc-dichloromethane, 80:20) to get 1.75 g (89% yield) of the title compound 13 as a pale brown solid and subsequent recrystallization (n-exane/diethyl ether) gave colorless crystals suitable for crystallographic studies. 1H-NMR (CDCl3): 3.97 (s, 2H), 4.74 (br s, 2H), 7.10-7.24 (m, 5H), 7.89 (s, 1H). MS (ESI): m/z 265 (M+H). The crystallography of compound 13 is shown in FIG. 3, demonstrating its purity.

Source