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, 6H), 2.0 (m, 1H), 2.4 (s, 3H), 4.0 (d, 2H), 4.02 (s, 3H), 7.3 (s, 1H), 7.8 (s, 1H); 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