(6R-trans)-4-((2-((3-((Acetyloxy)methyl)-2-carboxy-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-en-7-yl)amino)-2-oxoethyl)thio)-1-methylpyridinium 51159-12-7 7-(alpha-(1-Methyl-4-pyridiniothio)acetamido)cephalosporanic acid BL-S 217 BL-S-217