| 摘要 |
<p>7 beta -Amino-3-hydroxy-1-carba(1-dethia)-3-cephem-4-carboxylic acid esters are provided via cyclization of cis-3-(substituted amino)-1-(2-substituted 2-oxoethyl)-4-azetidin-2-one propanoic acid esters. The 7 beta -amino-3-hydroxy-1-carba(1-dethia)-3-cephem-4-carboxylic acid esters are useful chiral intermediates to beta -lactam antibiotics.</p> |
