反应详情

To a suspension of 3-acetoxymethyl-7-aminoceph-3-em-4-carboxylic acid p-toluenesulphonic acid salt (4.8 g) in acetonitrile:dimethylacetamide (6:1, 25 ml.) was added dropwise with stirring at room temperature a 3 M solution of 2-dichloroacetoxyimino-2-phenylacetyl chloride (syn isomer) in acetonitrile (5 ml.). The reaction was stirred at room temperature until the solution was homogeneous, then poured into saturated aqueous sodium bicarbonate solution. The solution was washed with ethyl acetate, acidified to pH 1.0 (2 N-hydrochloric acid) and extracted with ethyl acetate. The combined extracts were washed with water, dried and concentrated to ca. 10 ml. The concentrate was added dropwise to petroleum spirit (b.p. 40°-60°) with vigorous stirring. This produced a gummy solid which was stirred with ethyl acetate (50 ml.) and the solution filtered and added dropwise to petroleum spirit (300 ml.). The precipitated solid was filtered and dried to give the title acid (1.47 g; 29%), [α]D +57° (c 0.7 DMSO) λmax. (EtOH) 253.5 nm (ε 15,800).

1. additionwas added dropwise
2. washThe solution was washed with ethyl acetate
3. extractionextracted with ethyl acetate
4. washThe combined extracts were washed with water
5. customdried
6. concentrationconcentrated to ca. 10 ml
7. additionThe concentrate was added dropwise to petroleum spirit (b.p. 40°-60°) with vigorous stirring
8. customThis produced a gummy solid which
9. filtrationthe solution filtered
10. additionadded dropwise to petroleum spirit (300 ml.)
11. filtrationThe precipitated solid was filtered
12. customdried
13. customto give the title acid (1.47 g; 29%), [α]D +57° (c 0.7 DMSO) λmax