反应详情

To a solution of 2-(2-tritylaminothiazol-4-yl)-2difluoromethoxyiminoacetic acid (syn isomer) (0.8 g) and diisopropylethylamine (0.43 g) in N,N-dimethylformamide (20 ml) was added mesyl chloride (0.38 g) at -20° C. and the mixture was stirred at the same temperature for 30 minutes to give an activated acid solution. To a solution of 7-amino-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (0.57 g) and N-trimethylsilylacetamide (1.8 g) in tetrahydrofuran (20 ml) was added the activated acid solution obtained above all at once at -10° C. After being stirred at the same temperature for an hour, the mixture was poured into water and adjusted to pH 2.5 with an aqueous solution of sodium bicarbonate. The precipitates were collected by filtration and washed with water to give 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (1.1 g).

1. customto give an activated acid solution
2. customobtained above all at once at -10° C
3. stirringAfter being stirred at the same temperature for an hour
4. filtrationThe precipitates were collected by filtration
5. washwashed with water