反应详情

2-Allyloxyimino-2-(2-formamidothiazol-4-yl)acetic acid (syn isomer) (0.80 g) and dry ethyl acetate (10 ml) were added at 0° to 5° C. with stirring to a suspension of Vilsmeier reagent prepared from dry dimethylformamide (0.25 g) and phosphorus oxychloride (0.528 g) in dry ethyl acetate (0.75 ml) by conventional method, and the resulting mixture was stirred for 30 minutes at the same temperature to give an yellow solution. The solution was added at -10° C. with stirring to a solution of 7-amino-3-(1-allyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (1.11 g) and trimethylsilylacetamide (2.96 g) in dry ethyl acetate (15 ml), and the mixture was stirred for 1.5 hours at the same temperature. After addition of water (15 ml) to the reaction mixture, the ethyl acetate layer was separated and extracted with an aqueous solution of sodium bicarbonate (30 ml). The aqueous extract was acifified to pH 2.0 with 10% hydrochloric acid and extracted with ethyl acetate (150 ml). The extract was washed with water, dried and evaporated. The residue was pulverized with diisopropyl ether to give colorless powder of 7-[2-allyloxyimino-2-(2-formamidothiazol-4-yl)acetamido]-3-(1-allyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (1.48 g).

1. customto give an yellow solution
2. additionThe solution was added at -10° C.
3. stirringthe mixture was stirred for 1.5 hours at the same temperature
4. customthe ethyl acetate layer was separated
5. extractionextracted with an aqueous solution of sodium bicarbonate (30 ml)
6. extractionThe aqueous extract
7. extractionextracted with ethyl acetate (150 ml)
8. washThe extract was washed with water
9. customdried
10. customevaporated