反应详情

A mixture of 0.354 g. of 7-amino-3-(6-methyl-1-oxidopyridazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid, 0.42 g. of sodium hydrogen carbonate, 5 ml. of water and 5 ml. of acetone is cooled to 5° C and under stirring, 0.2 g. of diketene is added. The mixture is further stirred at room temperature for 30 minutes. The acetone is distilled off under reduced pressure and the residue is washed with ethyl acetate. The water layer is separated, brought to pH 2 with 50 % phosphoric acid, saturated with sodium chloride and extracted three times with ethyl acetate. The extracts are pooled, washed with a saturated aqueous solution of sodium chloride, dried over magnesium sulfate, concentrated and allowed to stand under cooling with ice. The resultant crystals are loosened with the addition of ether and recovered by suction-filtration. The procedure gives 7-acetoacetamido-3-(6-methyl-1-oxidopyridazin-3-yl) thiomethyl-3-cephem-4-carboxylic acid as crystals melting at 85°-87° C(decomp.). Yield 0.13 g. (30 %).

1. additionA mixture of 0.354 g
2. stirringThe mixture is further stirred at room temperature for 30 minutes
3. distillationThe acetone is distilled off under reduced pressure
4. washthe residue is washed with ethyl acetate
5. customThe water layer is separated
6. extractionextracted three times with ethyl acetate
7. washwashed with a saturated aqueous solution of sodium chloride
8. dry with materialdried over magnesium sulfate
9. concentrationconcentrated
10. temperatureunder cooling with ice
11. additionThe resultant crystals are loosened with the addition of ether
12. filtrationrecovered by suction-filtration