Phosphorus oxychloride → HCID 131711621, compound

Participants

Reaction Steps

7-[2-Methoxyimino-2-(2-formamido-1,3-thiazol-4-yl)acetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (10.8 g.) was added to methanol (200 ml.), and phosphorus oxychloride (7.2 g.) was dropwise added thereto with stirring and ice-cooling at 2° to 9° C. After stirring for 1.5 hours at the same temperature, the reaction mixture was concentrated under reduced pressure on a water bath of 25° to 28° C. to the volume of 100 ml. To the residue was added ether (300 ml.) with stirring and ice-cooling. Precipitates were collected by filtration and dried to give 7-[2-methoxyimino-2-(2-amino-1,3-thiazol-4-yl)acetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid hydrochloride (syn isomer) (12.3 g.). This powder (12.3 g.) was suspended in water (100 ml.) and dissolved by adjusting pH of the suspension to 7.5 by addition of a saturated aqueous solution of sodium bicarbonate. To the solution was added ethyl acetate (100 ml.), and the mixture was adjusted to pH 2.5 with 10% hydrochloric acid. Precipitates were collected by filtration, washed with cold water and dried to give 7-[2-methoxyimino-2-(2-amino-1,3-thiazol-4-yl)acetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (6.1 g.). The aqueous layer in the mother liquor was separated and stirred under cooling after addition of sodium chloride. Precipitates were collected by filtration to give the same object compound (3.8 g.). Total yield (9.9 g.). This compound was identified with the compound obtained in the foregoing Examples by I.R. and N.M.R. spectra.

Provenance & Evidence