反应详情

4-Nitrobenzyl 7-[2-(2-bromoacetyl)acetamido]-3-cephem-4-carboxylate (8.40 g.) was suspended in a mixture of tetrahydrofuran (150 ml.) and water (30 ml.) To the suspension were added acetic acid (50 ml.) and a solution of sodium nitrite (1.20 g.) in water (15 ml.) under ice-cooling, and stirred at 20° to 22° C. for 1.5 hours. The resultant solution was poured into ice-water (300 ml.) and stirred for 20 minutes. The precipitating substance was collected by filtration, washed with water, dried and then recrystallized from ethyl acetate to give 4-nitrobenzyl 7-[2-(2-bromoacetyl)-2-hydroxyiminoacetamido]-3-cephem-4-carboxylate (syn-isomer: 3.1 g.), mp 153° to 162° C.

1. stirringstirred for 20 minutes
2. filtrationThe precipitating substance was collected by filtration
3. washwashed with water
4. customdried
5. customrecrystallized from ethyl acetate