The bromination of 4-acetylpyridine (I) with Br2 and HBr in acetic acid gives 4-bromoacetylpyridine (II), which is cyclized with ammonium dithiocarbamate (III) and NaOMe to yield the thiazole (IV). The condensation of the sodium salt (IV) with the cephalosporanic ester (V) in THF affords the adduct (VI), which is treated with methyl iodide to provide the pyridinium salt (VII). The deprotection of (VII) with PCl5 and pyridine gives the aminocephalosporanic derivative (VIII), which is treated with TFA and anisole, yielding the inner salt (IX). Finally, this compound is condensed with the acid chloride (X) by means of NaHCO3 in THF/water to afford the target cephalosporin.

The bromination of 4-acetylpyridine (I) with Br2 and HBr in acetic acid gives 4-bromoacetylpyridine (II), which is cyclized with ammonium dithiocarbamate (III) and NaOMe to yield the thiazole (IV). The condensation of the sodium salt (IV) with the cephalosporanic ester (V) in THF affords the adduct (VI), which is treated with methyl iodide to provide the pyridinium salt (VII). The deprotection of (VII) with PCl5 and pyridine gives the aminocephalosporanic derivative (VIII), which is treated with TFA and anisole yielding the inner salt (IX). The reaction of 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(ethoxyimino)acetic acid (X) with PCl5 in ethyl acetate affords the 2-[5-dichlorophosphorylamino)-1,2,4-thiadiazol-3-yl]-2-(ethoxyimino)acetyl chloride (XI), which is finally condensed with the aminocephalosporanic acid (IX) by means of NaOAc and further hydrolyzed in acidic medium to provide the target phosphorylated cephalosporin.