Sodium Chloride → 7beta-(t-Butoxycarbonyl)amino-3-[2-(N-tosylcarbamoyl)-benzoyloxy]methyl-3-cephem-4-carboxylic acid

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Reaction Steps

In N,N-dimethylformamide (8 ml), is dissolved sodium 7β-(t-butoxycarbonyl)amino-3-hydroxymethyl-3-cephem-4-carboxylate (1.60 g), followed by addition of triethylamine (3 ml) and N-tosylphthalimide (1.80 g) under ice-cooling. The mixture is stirred for one hour and then poured into toluene (300 ml). n-Hexane (200 ml) is added and the resultant precipitate is collected by filtration, washed with toluene and dried. The powder thus obtained is dissolved in water (50 ml). The solution is adjusted to pH 3.7 with acetic acid and a saturated aqueous solution of sodium chloride (50 ml) is added. The resultant precipitate is collected by filtration and washed with water. The cake thus obtained is added to a mixed solution of ethyl acetate (30 ml) and water (10 ml). After separation, the ethyl acetate layer is washed with water and water (10 ml) is added. Sodium hydrogen carbonate is added to adjust to pH 6.8. After separation, the aqueous layer is washed with ethyl acetate and ethyl acetate (20 ml) is added. To the mixture, diluted phosphoric acid is added to adjust to pH 4.0. After separation, the ethyl acetate layer is washed with water, dried over anhydrous sodium sulfate and concentrated. To the residue, ether is added under stirring and the resultant insolubles are filtered off. The filtrate is concentrated under reduced pressure and carbon tetrachloride is added. The resultant precipitate is collected by filtration and dried over phosphorous pentoxide. The procedure provides 7β-(t-butoxycarbonyl)amino-3-[2-(N-tosylcarbamoyl)benzoyloxy]methyl-3-cephem-4-carboxylic acid (1.21 g).

Provenance & Evidence