| 摘要 |
Cephalosporins of formula (I): (where A is O or S; R1 is H or acetoxy; and R2 is COOH or a residue - COOCHR3-O-COR4 in which R3 is H or 1-4C alkyl and R4 is 1-4C alkyl or cyclohexyl, the residue -CHR3-O-COR4 being readily removable enzymatically), e.g. 3-acetoxymethyl-7- DL -alpha-amino-(5, 6-dihydro-1, 4-dithiin-2-yl)-acetamido -2-carboxy-8-oxo-5-thia-1-aza-bicyclo- 4, 2, 0 -oct-2-ene, their diastereomeric forms and mixtures, acid addition salts, metals salts, and addition salts with nitrogenous bases other than ammonia are new cpds. (I) are antibacterials active in vitro and in vivo against Gram-positive and Gram-negative bacteria. Thus, daily dosage against experimental Staph. aureus Smith infection of mice is 0.05-5 mg/kg s.c. or 0.05-30 mg/kg p.o., and daily dosage against E. coli in mice is 1-50 mg/kg s.c. or 5-500 mg/kg p.o. |
