| 摘要 |
NEW MATERIAL:The compound of formula I [R<1> is lower alkyl (substituted with carboxyl or carbamoyl); R<2> is carboxy or cyano; R<3> is carbamoyl or amidino; the bond designated with wavy line is anti-form or synform] and its salt. EXAMPLE:(z)-7-[alpha-( 2-Aminothiazol-4-yl )-alpha-( 1-methylethoxyimino )acetamido]-3- [4-(carbamoylcarboxymethylene)-1,3-dithietan-2-yl]-DELTA<3>-cephem-4-c arboxylic acid of formula II. USE:Antibacterial agent effective to Gram-positive and Gram-negative bacteria, especially to pseudomonas aeruginosa. PREPARATION:The cephalosporin compound of formula III [R<4> is (protected) amino; R<5> is (protected) carboxy, carbamoyl, or (substituted) lower alkyl; R<6> is OH or amino] is treated with a base such as potassium carbonate usually in a solvent at room temperature or under cooling.
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