反应详情

Isobutylchloroformate (4.79 ml) was added to a stirred solution of 2-amino-3-methoxy-5-methylpyrazine (5 g) and pyridine (2.91 ml) in dichloromethane (10 ml) at ambient temperature. After 90 minutes the reaction mixture was diluted with dichloromethane (10 ml) and washed with 2M hydrochloric acid (3×20 ml), water (20 ml) and saturated sodium chloride solution (20 ml) and then dried (MgSO4). Volatile material was removed by evaporation to give a solid which was recrystallised from hexane to give isobutyl N-(3-methoxy-5-methylpyrazin-2-yl)carbamate (6.5 g); 1H NMR (CDCl3): 1.0 (d, 6 H), 2.0 (m, 1 H), 2.4 (s, 3 H), 4.0 (d, 2 H), 4.02 (s, 3 H), 7.3 (s, 1 H), 7.8 (s, 1 H); mass spectrum (positive chemical ionisation (+ve CI)): 240 (M+H)+.

1. washwashed with 2M hydrochloric acid (3×20 ml), water (20 ml) and saturated sodium chloride solution (20 ml)
2. dry with materialdried (MgSO4)
3. customVolatile material was removed by evaporation
4. customto give a solid which
5. customwas recrystallised from hexane