This compound can be prepared by two related ways: 1) The condensation of (6R,7R)-7-amino-3-(3-oxobutyryloxy)-3-cephem-4-carboxylic acid (I) with 2-[5-(tert-butoxycarbonylamino)-1,2,4-thiadiazol-3-yl]-2(Z)-(methoxyimino)acetic acid (II), by means of PCl5 and bis(trimethylsilyl)acetamide (BSA) gives the corresponding amide (III), which is thencondensed with imidazo[1,2-b]pyridazine (IV) by means of KI in hot aqueous acetonitrile. 2) The condensation of 2-[2-(tert-butoxycarbonylamino)thiazol-4-yl]-2(Z)-(methoxyimino)acetic acid (V) with cephem compound (I) by means of PCl5 and triethylamine yields the corresponding amide (VI), which is deprotected with trifluoroacetic acid to afford free amide (III), already obtained.
Alternatively, the title compound can be prepared by acylation of the imidazopyridazinium cephem derivative (IX) with acid chloride (II) in the presence of NaOAc.