Cefdinir Open-Ring Lactone ; 

2-[(Z)-2-(2-Aminothiazol-4-yl)-2-(hydroxyimino)acetamido]-2-[(2RS,5RS)-5-methyl-7-oxo-2,4,5,7-tetrahydro-1H-furo[3,4-d][1,3]thiazin-2-yl]acetic acid sodium salt ;

CAS # 178422-42-9 (acid) ;

 C14H14N5NaO6S2;

Mol. Wt.: 435.41 ;