Reacción #62772

Ecuación de reacción

sodium bicarbonate

7-amino-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid

N-trimethylsilylacetamide

2-(2-tritylaminothiazol-4-yl)-2difluoromethoxyiminoacetic acid

diisopropylethylamine

mesyl chloride

→

7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid

Rendimiento 83.3%

Disolventes

tetrahydrofuran

N,N-dimethylformamide

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroto give an activated acid solution
2. 2
   Otroobtained above all at once at -10° C
3. 3
   workup.STIRRINGAfter being stirred at the same temperature for an hour
4. 4
   FiltraciónThe precipitates were collected by filtration
5. 5
   Lavadowashed with water

Procedimiento

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).

Fuente