反应详情

A solution of t-butyl 3-acetoxymethyl-7β-(pyrid-4-ylacetamido)ceph-3-em-4-carboxylate (3.0 g.) in acetic acid (30 ml.) was stirred, cooled briefly in ice and treated dropwise over 3-4 minutes with a solution of sodium nitrite (1.38 g.), in water (10 ml.). The mixture was stirred at 20° for 30 minutes and was then diluted with water and extracted with ethyl acetate. The organic extract was washed with saturated sodium bicarbonate solution and water and then dried over magnesium sulphate. Evaporation almost to dryness gave a residue which was dissolved in the minimum volume of acetone and added dropwise to stirred petroleum spirit (bp. 40°-60°). The resulting solid was collected, washed with petroleum spirit and dried to yield the title oxime as a white powder (2.9 g., 91%) which was shown (NMR) to be a syn/anti-mixture (30:/0).

1. temperaturecooled briefly in ice
2. extractionextracted with ethyl acetate
3. extractionThe organic extract
4. washwas washed with saturated sodium bicarbonate solution and water
5. dry with materialdried over magnesium sulphate
6. customEvaporation almost to dryness
7. customgave a residue which
8. additionadded dropwise
9. customThe resulting solid was collected
10. washwashed with petroleum spirit
11. customdried