| abstract |
CEPHALOSPORINS HAVING A 7-A-AMINOARYLACETAMIDO SUBTITUENT AND A NUCLEOPHILE ON THE 3-METHYL GROUP ARE PREPARED BY REACTION OF THE NUCLEOPHILE WITH THE NEW INTERMEDIATES, 7-(D-2,2-DIMETHYL-3-NITROSO-5-OXO4-ARYL-1-IMIDAZOLIDINYL-3-BROMOMETHYL-3 -CEPHEM4-CARBOXYLIC ACID SULFOXIDES AND THEIR EASILY HYDROLYZED ESTERS SUCH AS TRIMETHYLSILYL AND 2,2,2-TRICHLOROETHYL, FOLLOWED BY REMOVAL OF THE BLOCKING GROUPS, AS BY HYDROGEN CHLORIDE IN DIOXANE OR GLACIAL ACETIC ACID. THE INTERMEDIATES THEMSELVES ARE PREPARED BY BROMINATION, AS WITH N-BROMOSUCCINIMIDE, OF THE CORRESPONDING 3-METHYL COMPOUNDS. |