New acid 7- (2- (2-aminotiazol-4-il) -2-hidroxiiminoacetamido) -3-vinil-3-cefem-4-carboxilico (isomero sin).

CRYSTALLINE ACID 7 - (2 - (2 - AMINOTIAZOLE - 4 - IL) - 2 HYDROXYAMINOACETAMIDO) - 3 - VINYL - 3 - CEFEM - 4 - CARBOXILICO (SYN ISOMERO) THAT IS OBTAINED BY ACIDULATING A SOLUTION CONTAINING ACID 7 - (2 - ( 2 AMINOTIAZOLE - 4 - IL) - 2 - HYDROXIAMINOACETAMIDO - 3 - VINYL - 3 - CEFEM - 4 - CARBOXILICO (SYN ISOMERO) AT AMBIENT OR TEMPERATE TEMPERATURE. IT ALSO UNDERSTANDS PROCESSES FOR PREPARING SUCH A CRYSTALLINE COMPOUND AND PHARMACEUTICAL COMPOSITIONS CONTAINING IT AS AN ACTIVE INGREDIENT.