| 摘要 |
<p>NEW MATERIAL:A compound shown by the formula I (R is H, or amino-protecting group; R<1> is single bond, or alkylene; R<2> is H, or substituent group at 3-position of cephalosporin). EXAMPLE:7-[ 2-( 2-Amino-4-thiazolyl )-3-carboxymethylacrylamido ]- 3-pyridiniummethyl-3-cephem-4-carboxylic acid. USE:An antibacterial agent. Showing improved activity especially against Gram- negative bacteria. PREPARATION:An amine shown by the formula II or its reactive derivative is reacted with a carboxylic acid shown by the formula III or its reactive derivative in the presence of a condensation agent (e.g., carbodiimide) in a solvent at -30-100 deg.C, to give a compound shown by the formula I .</p> |
