Reaktion #683083

Reaktionsgleichung

tert-butyl 5-methylpyrazin-2-ylcarbamate

NBS

→

tert-butyl 5-(bromomethyl)pyrazin-2-ylcarbamate

Lösungsmittel

CCl4

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was cooled to room temperature
2. 2
   Einengenconcentrated
3. 3
   workup.DISSOLUTIONthe residue was redissolved in EtOAc (˜50 mL)
4. 4
   Waschenwashed with dilute aqueous NaOH twice (10 mL 1 N NaOH diluted in 20 mL H2O), brine (30 mL)
5. 5
   Trocknendried (Na2SO4)
6. 6
   Einengenconcentrated
7. 7
   SonstigeThe residue was further purified by flash chromatography on silica gel
8. 8
   Wascheneluted with gradient EtOAc/CH2Cl2 (0-30%)

Vorschrift

A solution of tert-butyl 5-methylpyrazin-2-ylcarbamate (2.79 g, 13.33 mmol), NBS (2.61 g, 14.67 mmol) and AlBN (0.219 g, 1.33 mmol) in CCl4 (45 mL) was purged with Argon, then the solution was heated with 85° C. oil bath for 4 h. The reaction mixture was cooled to room temperature, concentrated and the residue was redissolved in EtOAc (˜50 mL), washed with dilute aqueous NaOH twice (10 mL 1 N NaOH diluted in 20 mL H2O), brine (30 mL), dried (Na2SO4) and concentrated. The residue was further purified by flash chromatography on silica gel eluted with gradient EtOAc/CH2Cl2 (0-30%) and tert-butyl 5-(bromomethyl)pyrazin-2-ylcarbamate was obtained in off-white solid. LCMS (m/z): 288.1/290.1 (MH+), 0.82 min; 1H NMR (400 MHz, CDCl3) δ ppm 9.26 (s, 1H), 8.32 (d, J=1.2 Hz, 1H), 7.62 (br. s., 1H), 4.56 (s, 2H), 1.56 (s, 9H).

Quelle