Salts in the preparation of cephalosporin antibiotics

1 Compounds of general formula (II), wherein Rrepresents and M represents a dialkyl or dicycloalkyl ethylenediamine group selected from N,N′-diisobutylethylenediamine, N,N′-dicyclohexylethylenediamine, and N,N′-dicyclopentylethylenediamine, are useful in a process to make cephalosporin antibiotics of formula (I) wherein R represents hydrogen or pharmaceutically acceptable esters or alkali metals salts.