反应详情

温度

80 °C

In a 2-L flask, 3-methylpyrazine-2-carboxylic acid (Matrix, 19.95 g, 144 mmol) was suspended in MeOH (500 mL). The suspension was cooled in an ice-water bath, and concentrated sulfuric acid (Fluka, 27.3 mL, 506 mmol) was added over a time period of 5 min. The reaction mixture was heated to 80° C. for 5 h. The reaction mixture was concentrated under reduced pressure and the residue was taken up in DCM (750 mL). The excess acid was neutralized carefully with aqueous NaOH (5M, 200 mL). The aqueous layer was separated and extracted with DCM (250 mL). The combined organic layers were combined, dried over MgSO4 and concentrated to afford the title compound (16.15 g, 106 mmol, 73%). MS m/z=153 (M+H).

1. temperatureThe suspension was cooled in an ice-water bath
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. customThe aqueous layer was separated
4. extractionextracted with DCM (250 mL)
5. dry with materialdried over MgSO4
6. concentrationconcentrated